Posts Tagged ‘Modification

25
Feb
18

Dismantling a hard drive

Note that in the following post I’m describing taking a hard drive apart in order to reuse some of the parts, but have no intention of putting it back together, or making it work again as a hard drive!

This the 3.5″ hard drive I took apart as my first experiment:

Front & Back IMG_1515

I’m sorry the PCB side is rather blurry, but I was less interested in that than what was inside.

The tools required for the job were a small screwdriver set, from which I mostly used a Torx or ‘star’, which I think was size 8, and a very small Philips or crosshead for a couple of screws inside:

Tools IMG_1525

I also needed a large flat-bladed screwdriver, which I used two or three times.  If you’re going to do the same, you may find a few differences in the details – type and positioning of screws, differently shaped fittings, and so forth, but the principles should be the same.

I first removed the circuit board, and put that aside.  Turning it over, you can clearly see in the first picture the 6 screws round the edge of the ‘lid’ which needed removing.

Having taken these out, it seemed that the top was glued in place as well as screwed, so I went round with the large screwdriver, prying it open.  This almost freed it, but it was only after still experiencing considerable difficulty in getting it completely open that I realised there must be another screw somewhere in the middle, under the label.  I scraped away the label until I found it and took it out.  The arrow shows where it was.

Top IMG_1527

I was then able to take the lid right off and expose the inner workings – of which there aren’t actually that many.

Top removed Captioned IMG_1528

The picture shows the disk or disks, one on top of the other, like a stack of pancakes – except there are gaps between them, and the arm is actually several arms, one for each disk; the arm itself with the delicate heads on the end which read the data from the disks, and with its other end moving between two magnets (not visible at the moment); and finally a flexible plastic multi-way ‘cable’ which joins the arm – and some small circuitry on the arm – to a connector.  This would have poked through a gap in the case to connect to the circuit board  on the other side.

Later on, connections will have to made to some very, very tiny points on the arm, and it’s going to be a lot easier to trace these points back to the connector, so its important not to damage the plastic cable.  The connector could be poked out from the other side, once it two fixing screws had been removed.

The fitting obscuring the back end of the arm wasn’t – in this model of drive anyway – screwed in place, it was just slotted on some pins and just needed prising off.  I believe the magnets in hard drives are made of neodymium.  This is classed as a ‘rare earth’ (although it’s isn’t actually any rarer than, say, copper) and makes very strong magnets.  Just be a bit careful as you remove them, and think where you’re going to put them down as you can be surprised at how firmly they grab lighter metal objects.

This picture shows the top magnet fitting removed:

Top Magnet Out Captioned IMG_1529

Once the top magnet is off, it’s possible to move the arm out of the way and get the disks out.  This involves removing 6 screws around the centre (on top of the motor) and two screws at the side. the disks and the various fittings associated with them all come off in layers.  The disks – there were three of them in this drive, look very much like CD’s, with a large hole in the middle, except they’re made of metal.

I put the disks carefully to one side – I had an idea they might be good for chimes or cymbals – and focused on the arm.

With the top magnet out of the way, it was possible to see the so-called ‘voice’ coil’.  Two impossibly tiny wires connected the voice coil with the arm actuation circuitry, and to test that the arm was working I needed to attach a battery to these wires.

In the end these wires were just too small, so I traced them back through the plastic cable to the connector, where it was slightly easier to get at them.  Attaching the battery leads to the two points produced nothing at 4.5v, but at 9v there was a loud and satisfying clunk, which showed that the arm was working fine.

*

The procedure with the next disk I worked on, a smaller 2.5″ was exactly the same.  The top came off once I had removed the 6 visible screws and the 7th screw hidden under the label.  I needed a smaller Torx/star screwdriver – a size 5 or 6 – for this disk compared to the other one.

1_IMG_1555

This exposed the single disk and arm:

2_IMG_1557

A single screw in the middle of the motor housing allowed the disk to come out.

3_IMG_1558

Removing two screws freed the unit in the bottom right, which connected the arm with the circuit board on the other side.

4_IMG_1559

I prised off the top magnet (bottom left), just to make sure the construction was the same as the 3.5″ drive – which it was.

I replaced the magnet and tested the drive with a battery.  I’d already removed a plastic retainer on the right, by the heads at the end of the arm; I also had to remove the plastic piece which you can see on the left, which was restricting the arm’s movement.  However, once I had done this, applying 9v to the appropriate pins on the connector reliably operated the arm.

In fact, this smaller mechanism would also work with 4.5v, which was a useful discovery.  If parts of the circuitry which would operate it had to be quite low – say, 5v – it could be handy if the arm would also work at the same voltage.

*

So, I had verified that an arm from an inexpensive broken hard drive could operate as an electrically-operate striker, like a solenoid; that arms from both 3.5″ and 2.5″ drives would work; that the 3.5″ drive arm would operate at 9v; and the 2.5″ drive arm would operate at 4.5v.  It will be some time before I get round to the next part of this project, but the next thing will be to see how the arms could be set up to operate outside the hard drive housing.

04
Nov
13

Fun with the Apple IR Remote, Part 3: Additions

In the previous post in this series, I dismantled and modified a white Apple infrared (IR) Remote control.

In this post I describe a foot controller which can be plugged into the DB9 socket on the modified remote, and then go on to consider what you can do if your Mac doesn’t have an IR receiver built in.

I had already constructed a very simple foot controller, which I had used with the Superstylonanophone.  The controller was  – well it was exactly what it looks like: a length of plastic guttering with a few push switches inserted into it, and a multi-way socket.

Footswitches1

There were just 4 buttons on the foot controller: two for bass drums and two for hi-hats.  These were connected very simply underneath: one side of each switch was a common connection, the other sides went to 4 appropriate pins on a 15-way D socket.

Footswitches2

It occurred to me that the same controller could also be used for the IR Remote, which also required a number of push switches with a common connection.  There would need to be more of them – at least 6 – and an alternative 9-way connector, but provided both connectors weren’t used at the same time, the controller could operate either device.

I had some spare buttons of the same type, so I added 3 extra ones in the spaces between the 4 originals (not in a very straight line between the 4 originals, it has to be said!), a new DB9 connector, and an LED which would come on when the foot controller was connected to the modified remote.

Outside DSCF0004

Only 6 of the buttons were required to duplicate the functioning of the Apple remote.  Using my IR Remote Tester in iRedLite, I verified that all the button presses – short, long and double – were being received and transmitted correctly from the six buttons I had wired up.  I connected the seventh so that the LED – which can be seen illuminated at the bottom of the picture – would go out if it was pressed, as a warning that it had no function.

Inside DSCF0003

I moved the bass drum triggers to the two leftmost buttons, and hi-hat triggers to the two rightmost.  At some point, when I revisit the Superstylonanophone, I can consider adding in further drums as there are now 3 spare buttons in the middle of the controller.

Connection DSCF0002

*

The foregoing is all very well if you have a MacBook, MacBook Pro or whatever, which has a built-in IR receiver – but what if your Mac doesn’t have this capability?

Fortunately, if this is your situation, all is not lost.  As I implied when discussing Joystick and Gamepad Tester, the Mac’s IR receiver is part of the USB system – this can be verified by checking the machine’s System Profiler:

system profiler ir receiver2

So, to add IR control, the ideal thing to get hold of would be an Apple IR receiver module which has a USB connection.

Luckily just such a device exists!

There may be a number of these, but the one I got was either Apple part number 922-7195 or 922-8355, not sure which: one is from a MacBook 15″, the other from a MacBook Pro; both have an IR receiver input and a USB output, so I daresay both would work equally well in this application.

IR Rec module IMG_0679L

I bought mine here: http://www.powerbookmedic.com/MacBook-Pro-Infrared-board-p-18041.html at a cost of less than £10, including postage from the U.S. – a bargain!  [Edit: and apparently still available 5 years later!  The part is still shown for sale on that website in October 2018.  The current MacBook/MacBook Pro no longer has this IR receiver in it].

I got the idea for this part of the IR project from this article: http://photos.pottebaum.com/2009/IR.  The aim was to install this module in a new case with a USB lead, thus enabling a Mac with no IR receiver to benefit from the remote, or to use  the remote at a distance or from an angle where a direct line of sight to the computer wasn’t available.

The new case I chose was this one:

IR REC front IMG_1567

It’s a Fisher Price ‘CD Player’.  It doesn’t, in fact, play CDs at all, but I picked it partly because of a definite stylistic connection with the modified Apple remote described above, partly because of its large front ‘window’ – which might allow for a certain degree of repositioning of the IR receiver inside – and partly because it was powered by three AA batteries, somewhat similar to the 5v provided by USB.

IR Rec back IMG_1568

I undid the 6 screws in the back (four of them are already out in the above picture, the two at the top remain), revealing the internal structure.

IR Rec inside IMG_1571

It was very well made, and very difficult to get apart as a matter of fact, as the two large white surfaces you can see were glued together.  It looked like blobs of a sticky adhesive which stretched when pulled, so I was able to prise the two halves apart slightly and cut the glue with a craft knife.

The speaker is visible in the top right-hand corner.  One of the three circuit boards in the unit can be seen at the bottom of the back section; the other two are underneath the two sides of the front section.

Circuit boards IMG_1569

The 8 press switches that can be seen on the tops of the circuit boards are operated by the 4 buttons on the front of the unit.  The switches are in pairs and the two switches in each pair are identical.

I tested each switch in turn and noted their outputs.  They worked by cycling through a number of samples: a short bell-like tune, some spoken phrases (‘Sing with me!’, ‘Oh, yeah!’ and ‘Let’s Boogie!’) and some longer songs with voices and instruments (‘One, two, buckle my shoe’, ‘Itsy-bitsy spider’, ‘Row, row, row the boat’, and some songs that sounded as if they may have been specially written for the unit).  Three of the pairs had a 9-step sequence, one of them a 6-step.

I wasn’t, in this instance, interested in the songs, as I wasn’t intending to circuit bend the device, but I wanted the LEDs to come on when IR input was received.  The best LED display was seen while a song was playing; during the bell tune and the spoken phrases the lights came on only for a short time.  The sequences weren’t the same for each button, and I decided that button three (bottom left)  was the best one to concentrate on, as there was a higher proportion of songs in the sequence compared to short phrases.

Steps in the sequence were initiated simply by a short +V pulse to an appropriate point on the PCB, which should be easy to generate.

*

First of all, however, I needed to connect up the IR receiver module.

Being color-blind, I’m always nervous about connecting up colour-coded wires – especially to a USB plug which would be going into my laptop.  However, the module seemed – to my eyes at least! – to follow the conventional red-white-green-black USB wiring scheme (+5v, Data +, Data -, Ground, in that order), so I snipped off the small 4-way connector it came with and connected the four wires to a short length of multi-core cable.  The other end of the multi-core cable was connected to a USB plug, via a small PCB connector.  There was no PCB: this was just a convenient way of joining together various wires – the four USB wires, power leads from the batteries and some others I’ll explain shortly.

So, the Apple IR receiver module was connected to a USB plug.  I didn’t want the unit to have a long lead trailing out from it, so the lead to the plug was kept very short, and plugged into a small USB hub which I fixed to the battery compartment lid on the back of the unit:

hub IMG_1585

hub 3 IMG_1587

It was an excellent little hub – only £2 or £3 on eBay, and capable of being powered, if required.
Now ready for testing, the unit looked like this:
Back&Front_IMG_1603

The new receiver module can be seen lying in the middle of the front of the unit.  The short USB lead and plug can be seen emerging from the back, and at the bottom of the picture the mini-USB lead goes from the hub to the laptop.  The purpose of the three unused wires in the multi-core cable is explained later on, and is not to do with the Apple receiver.

Checking in the System Profiler, I now saw two IR Receivers instead of one:

System profiler 2510

I experimented simply by covering up one or other of the receivers and making sure, using iRed Lite, that my remotes – especially the new modified one – were able to control various functions in Safari and would print the correct numbers in Text Edit.  The two receivers seemed to work in tandem on the MacBook – it didn’t matter which of the two I covered up, the other would immediately register the button presses and carry out the required function.

*

The vital question was: what would happen if I connected the unit up to a computer that didn’t have a built-in IR capability?

I started with my eMac, which runs the same OS as the MacBook, 10.5.8.  I checked the System Profiler – no mention of an IR receiver; then I plugged the unit in and was gratified to see the IR receiver shown (I needed to close the System Profiler and reopen it to make the new device show up):

eMac before&after IMG_1605

I didn’t have Joystick and Gamepad Tester or iRed Lite installed on the eMac, so I had to content myself with testing the functions the remote normally performs on a Mac – opening and closing Front Row and turning the volume up and down.  Using the new modified remote, I confirmed that it would do this.

I then tried the same procedure on an old G5.  I can’t remember what OS it uses, but I think it’s either 10.5 or 10.6.  Once again, using the System Profiler, I verified that no internal IR receiver showed up at first, but when plugged in the new device was registered:

G5 before and after IMG_1608

The one thing that did appear first of all in the USB section was my iPazzPort.  I’ve described in a past post what this is – a very handy little device, no more than 4 or 5 inches tall, which duplicates the function of the keyboard and trackpad:

iPazzPort_IMG_1607

As can be seen, it connects via USB – not a problem, even on the G5, which only has one USB socket on the front, as I was able to plug it into the hub on the back of the new receiver and use the two devices together.

Once again, the remote worked exactly as intended, proving that IR functionality could be added to a Mac which originally had none.

*

I didn’t immediately reassemble the unit, as there were a couple more things I wanted to do with it.  First of all, as mentioned earlier, I wanted to include a method of making the lights flash when an infrared signal was received from the remote.  As described, this needed something to give a +V pulse when the signal came in.

I didn’t want to interfere with the Apple receiver module, so added a second IR receiver like this:

AX1838

This device, an AX1838, has three leads: two for the power supply, with the third giving an output when it detects an IR input.  It wouldn’t be necessary to interpret the input – which is what the Apple module does – just give an output pulse on receipt of a signal.  Unfortunately, according to the data sheet, the output of the device goes low when IR input is detected, not high, which is what the ‘CD Player’ circuit requires.

I was under the impression that the low level output from the device would be sufficient, when inverted, to operate the switch in the CD Player, but this wasn’t the case.  In the end I looked around at circuits for simple infrared-operated switches, and used an adapted version of this one, using just three components, a BC588 transistor, a 22μF capacitor and a 100k resistor.

Apart from the existing electronics concerned with playing the samples and sequencing the lights, the electronics I added to the device looked like this:

IR Receiver Electrics Revised2

In fact, this is what I intended, but as I didn’t have a 100Ω resistor, I added a 470Ω instead.  I don’t know if this was too large a value, but I’ll find out when I come to use the wii later.

I didn’t bother with a piece of stripboard, I just wired everything up to the three legs of the transistor.  This addition to the circuit seemed to have the desired effect: the output of the transistor is normally kept low; an incoming IR signal is detected by the AX1838 and as the capacitor charges up the multiple signals are smoothed out into one.  The output of the transistor goes high and is boosted to a level sufficient to operate the CD Player switch and turn on the lights, giving a visual indication that an instruction has been received by the Apple IR receiver.

Stiff wires were attached to the two IR detectors, anchored inside the unit, so the detectors could be repositioned within the CD Player front window.

*

Finally, while on the infrared theme, I just had two more things to do  before reassembling the finished unit.

Firstly, I added two infrared LEDs to the front of the unit.  These had nothing to do with the receiver or the flashing lights: they’re a little closer together than the original, but they’re designed to duplicate the function of the wii ‘sensor bar’.

IR LEDs IMG_1609

I’ll be blogging about the wii system later, but the ‘sensor’ bar’ is a most inaptly named device, since it doesn’t ‘sense’ anything at all, but instead provides two points of infrared light which the wii remote controller – or ‘wiimote’ – uses to fix its position.  Being a little closer together than the Nintendo original isn’t a problem – the wiimote might just think it was further away from the sensor bar than it really was.  As I’m not proposing to use my wii controller for playing sports, I don’t anticipate a problem with this.  Further information will appear in my wii posts.

The new infrared device had one more secret, hidden in the carrying handle:

Candles 1 IMG_1612

There are many reports on the internet of wii users who have substituted candles for infrared LEDs when using their wiimote, so I thought I’d guard against battery failure in the unit by adding candle holders – the kind you buy for birthday cakes.  Believe it or not, this does work!

*

Front & Back

After reassembling the unit, and thinking again about the wii remote, I added an extra external item to the USB hub: a tiny Bluetooth dongle.  I found this in Poundland, for £1 (obviously!) and thought for that price it would be worth experimenting with.

22
Oct
13

Fun with the Apple IR Remote, Part 2: Modifications

In the first part of this series of posts, I described the Apple infrared (IR) Remote system and some software which allows you to use the IR signals for controlling apps on the Mac.

In this post I take a closer look at the Remote controller itself, and describe the way I modified mine.

I must say that I’m not familiar with the silver aluminium remote, although I have no reason to believe it’s substantially different on the inside from the original white remote.  This is the one I have experience of.

What’s good about the white remote is also what’s bad about it – it’s very tiny.  This is great if you just want to tuck it away somewhere and not have a bulky TV/DVD player-type remote to lug about, but not so good from the point of view of it easily being overlooked or mislaid.

So, one reason you might want to modify the remote is to make it larger and more suitable for the human hand.

Frankly, the most cunning solution to his problem is the one described here by Brad Moon.  I hope he won’t mind me using his picture:

Remote wood block

Yes, what Brad has done is simply to glue his Apple remote to a hand-sized piece of wood.  Job done!  As he says in his blog post: ‘Too big to lose, too big to slip behind a cushion or slip into a pocket . . . The Apple TV remote hack has been in place for roughly a month.  In that time, the remote has been lost exactly zero times.’

This certainly takes care of the problem of the unit itself being rather small, but to address the problem of the size of the buttons themselves and their awkward layout, the unit has to be taken apart.  At the time of writing, you can still get hold of these white remotes on eBay for about £3, so if you want to try this, there’s no need to sacrifice the one that came with your Mac.

This is how it’s done:

1_IMG_1533

The picture above shows the unit and the tool (or maybe one of the two tools) you need to open the remote unit.  This is a small Philips or crosshead screwdriver.

As well as being used in a moment for taking out screws, the first thing you can do with it is poke the small depression on the right-hand side of the base of the remote unit.  This releases the battery tray, which pops out on a spring:

2_IMG_1534

Next, you have to undo a screw which is right down inside, next to the release button:

3_IMG_1536

Undo the screw and take it out:

4_IMG_1535

The next bit is the most difficult.  On the opposite side – the lower side in these pictures – is the spring which pushes the battery compartment out.  The spring is firmly attached to the bottom of a small piece of plastic, and you have somehow to grab this piece of plastic and pull it out, with the spring on the bottom of it.

The next picture shows what the spring and the plastic piece look like.  You might reach in and grab it with tweezers or narrow long-nosed pliers, but it’s right up against the edge of the case, and hard to get hold of:

6_IMG_1538

If you look at the full-size version of the picture, you can see that the piece of plastic has tags on it, so I was able to poke the screwdriver under a tag and drag the plastic and spring out.

Underneath where the spring was is another small screw.  Unscrew this and take it out:

7_IMG_1539

You can then pull the battery compartment out.  I did this with a pair of narrow pliers, gripping the white release button, which you can see in this photograph.

8_IMG_1540

Then you can push out the remaining parts left inside the case.  I did that by inserting the screwdriver here:

9_IMG_1541

The circuit board, with the springy battery connectors behind, slid out very easily:

10_IMG_1542

You can carefully detach the end  piece from the circuit board, clicking it off the tabs which hold it in place over the end of the board and the IR LED:

11_IMG_1543

This an exploded view of the remote, with all the parts visible:

11B_IMG_1547

Putting it back together, of course, is the reverse of this procedure.  The trickiest part is undoubtedly getting the spring and its plastic top back in.  This video by Andrew Williams, to which I’m greatly indebted: http://www.youtube.com/watch?v=vuP6CH770NM shows a remote being put back together, and explains the direction in which the tabs must face – front and back – for the plastic piece to go back in the correct position.

*

I wasn’t interested in putting it back together again, so I looked more closely at the circuit board:

12&13_IMG_1545&6

You can see in the top part of the picture the infra-red LED and the 6 buttons.  You can also see 4 screws which attach the circuit board the the plastic fitting.

The first thing to do was take off the six silver ‘domes’ which make the contacts when the buttons are pressed, and see what connections they made.  These are often, in my experience, attached together to a transparent sticky sheet which peels off, and so it was in this case.

Remote PCB IMG_1554

As you can see from this photograph – taken after I’d removed the four small screws holding the PCB to the plastic fitting – each button makes a contact between an outer ring and a centre spot.  All the outer rings were connected together, to what looked like +V, while the six centre spots were separate.  What I wanted to do was transplant the board into a larger unit, so I needed to solder seven wires to the board, and connect them to buttons in the new unit.

The larger unit I’d chosen was this one:

vtech_tinytouch_phone

This is a vtech Tiny Touch Phone: it’s powered by two AA batteries – 3v, same as the Apple Remote; has 12 buttons – exactly twice as many as the Remote, which could be handy for dissociating short, long or double presses; and has flashing lights – which is always good.  It also makes sounds, and under normal circumstances I would be looking to ‘bend’ these, but in this instance making noises wasn’t what the project was all about, so I decided I’d remove the sounds completely by taking out the speaker.

The Phone also has a hollow plastic ‘antenna’, which was perfectly placed for installing the IR LED.

aerial

This is what it looked like inside.  In  this picture the large mechanical unit, which looks like the film sprockets in an old 35mm film camera is obscuring the speaker housing.  With the speaker removed there looked as though there’d be plenty of room for the small Apple Remote PCB there.  The wires for the LED could easily pass from there up into the antenna.

Phone inside IMG_1552

The general idea would be to rewire the button connections on the Apple Remote PCB to the Tiny Touch Phone buttons.  The Phone buttons (visible in the first picture above) are, however, hollow, and make connections with a membrane, rather like  QWERTY keyboard, via their edges .

I wanted to leave the membrane intact, to operate the flashing lights, so I decided to add small tactile switches with longish 3.5mm actuators which would be glued in the hollows with the actuators sticking out through a hole in the top of the Tiny Touch buttons.  It was these switches which would actually operate the IR remote.

Gluing these in without gluing them together so they wouldn’t function proved difficult.  Letting superglue anywhere near them – even the gel type which I usually use – could prove fatal, as it has a habit of running everywhere.  In the end I used epoxy, which is stickier and less runny, and tiny pieces of tissue paper soaked in epoxy to keep the switches in place.  The moon and star buttons aren’t hollow, so I stuck tactile switches with short 1mm actuators to the top of them, on the outside, with wires running in through a small hole.

In the end I only connected up the star: it would have been difficult to make the hole in exactly the right place in the moon and route the wires inside without disturbing the membrane too much.  The star operates the ‘Menu’ button, which is less important than the others and doesn’t require more buttons to distinguish types of presses.

Buttons IMG_1550

In the event, all but one of the tactile switches worked after this treatment, which was OK, as there were two new buttons for each button on the original remote, so all functions would still be available.

To modify the new unit, I first removed the speaker and replaced it with a resistor (two 22Ω resistors in parallel, actually, as I had these lying about.  I didn’t have any 8Ω resistors to match the speaker, but 11Ω, I reasoned, was close enough).

This created enough space in the top of the unit for the small Apple remote PCB.

I reinstalled the buttons in their places and connected the tactile switches together.  One side of each switch was connected to +3v, the other sides of the switches were connected together in pairs (except the moon, as explained above).  This made 7 extra wires running down to the bottom of the unit.  The presence of the wires might have an effect on the operation of the TouchPhone’s original buttons, but this wasn’t important as their only function now was to light up LEDs when the remote was operated, a feature which Apple neglected to provide in the original.

Buttons_connector_IMG_1574

As can be  seen in the above picture, there was just about enough room for a 9-way D socket in the base of the unit.  I put this in partly because it would allow for external operation of the 6 remote buttons – perhaps by means of a footswitch – and partly because it provided a handy link point between the tactile switches and the Apple remote PCB.

To attach the remote PCB, wires were connected to the centres of the 6 switch points, and one of the outer rings, which were all connected together on the board.  3v and 0v power cables were connected to the springy metal pieces which formerly connected to the coin-battery in the original remote housing.  These connectors were shortened in order to fit the PCB neatly in the space where the speaker had been.

PCB_LED_IMG_1577

At the same time I detached the infrared LED and put it on the end of a longer lead, so it would reach to the front of the unit when in operation.

At this point everything was connected up, although not back in place, so I made a quick check, using iChat and the laptop camera in the way described before.  I pressed all the buttons in turn, pointed the unit at the camera, and watched for the infrared LED to come on.

When I was satisfied that it did so, I replaced the membrane and the TouchPhone PCB, as this would make pressing and testing the buttons a great deal easier.

*

For the next step I needed a way of thoroughly testing if the remote worked as intended.  I did this by creating a Tester program, using iRedLite.

It takes quite a few steps to create a ‘Layer’ – a set of instructions for each remote button – in iRedLite, but this is how I created a ‘Remote Tester’.

The ‘Menu’ button has special functions in iRedLite, but the other 5 buttons respond to short presses, long presses and double presses, so 15 separate instructions would be required.  What I decided to do was use Text Edit, and simply have it print the numbers 1 – 15, according to which remote button was activated.

Step 1 was to open iRedLite.  You can set it up in various ways in the preferences, but I have it set so it just opens an icon in the menu bar:

1 iredlite menu bar

The first step is to select the Editor from the drop-down menu:

2 Show editor

This brings up the Editor screen.  The top half of the window is a copy of what iRedLite calls the OnScreen Display (OSD).  The bottom half allows you to edit Layers and Buttons, and select the actions the buttons perform.  I began by creating a new Layer for my Text Edit actions:

3 New Layer

Then I entered the details of this Layer:

4 Name new layer

I typed a name for my Layer into the ‘Title’ box, and then made choices about what would happen when the Layer was selected.  I chose not to have the Layer activated when I switched to Text Edit, in case I wanted to type some text while using iRedLite with another application; but I did choose to have Text Edit activated when I switched to this Layer, because the actions all required text to be typed in it.  I have several remotes, so to be certain which remote was being tested, I set it to respond only to a particular one: in this case, the one with the ID No. 214.

Having finished creating the Layer, I clicked on the small arrow in the bottom right-hand corner of the Editor window.  I believe they call this the ‘Expert’ button, but it’s simply for accessing the section where actions are created and organised.

5 Editor window

Clicking this button opens the right-hand side of the Editor.  In here, if you look in the ‘Application’ column and can’t find the application you intend to use the remote with, click the ‘+’ button at the bottom of the column to add it to the list:

6 New Application

Type the application name in the box which appears.  The program will be recognised if its name is written the same as it would appear if you moved your mouse over it in the Dock.  Text Edit is actually written ‘TextEdit’, so that’s what I typed in the box:

7 Type New Application

Next you have to create a ‘Group’ – not for any special reason, I don’t think: it just works that way.  If you create a lot of actions for one particular application, this allows you to put different types of actions together, i.e. Keystrokes in one Group, AppleScripts in another, and so on.

I just wanted keystrokes, so I created a group called ‘Keys’.  Group names are your personal choice.  Once again, I clicked the ‘+’ sign under the ‘Groups’ column, and typed ‘Keys’ in the box which appeared.

8 New Group

Then it was time to create some actions.  Each action is entered individually, so I had to click on the ‘+’ sign at the bottom of the ‘Actions’ column 15 times, name the actions in the boxes which appeared, and specify what was to be done.

They were all more or less the same, and this is an example:

9 Create actions

Click the ‘+’ sign; name the action – again, this is entirely your choice: I just called them ‘1’ to ’15’; type the name of the application, or choose it if it appears in the drop-down list; check the box if you need the application to come to the front – which I did, because I wanted to read what it had printed; and type in what keystroke or keystrokes should be made.

Allocating the actions to the buttons is just a matter of dragging and dropping the action onto the appropriate button, and clicking ‘Assign Action’:

10 Drag and drop

The button will be given the name of the action – in this case ‘1’, which is the name I had given to the first action, which was to print the number 1.

11 Button number 1

You can rename the button, and I did, calling it ‘1/2’.  This is the reason why:

iRedLite shows the pattern of buttons in the way that it does to indicate that the button nearest the centre performs the short press action (which they call ‘Action on click’), while the button on the outside performs the double press action.  In reality, of course, these actions are performed by pressing exactly the same button on the remote, but it makes it clearer to see which number of presses produces which action.

So the ‘short press’ and the ‘double press’ are specified, but the ‘long press’ action (which they call ‘Action when holding’) remains to be allocated.

I decided to add the long press action to the instructions for the inner buttons, so in the example below I selected the appropriate inner button (Action 4, the ‘+’ button on the remote) and the ‘Advanced’ tab.  This allowed me to drag and drop the action I wanted to be performed as the long press action, printing the number ‘5’.

12 Button 4_5

I added a long press action to buttons 1 (the ‘Left’ button on the remote), 4 (the ‘+’ button), 7 (‘Right’), 10 (‘-‘) and 13 (the centre button) and renamed the buttons in iRedLite accordingly (‘1/2’, with ‘3’ being the double press action for that button on the remote; ‘4/5’, with ‘6’ as the double press, and so on).

When I’d finished, the set-up looked like this:

13 Finished

Note the button in the top right-hand corner,  marked ’15’.  There are 12 more places in the grey area of the button window where you can drag and drop actions, 6 on the left and 6 on the right.  If you drag and drop an action somewhere in the grey space, a new button will be created there.  This might come in handy if you had a modified control with differently positioned buttons.  In this case, I used one of the spare places for the double press action associated with the centre button.

Removing buttons, should this be necessary, is one of the functions on the drop-down menu where I chose ‘New Layer’ at the beginning.

I opened Text Edit and pressed all the buttons in order, single press first, then long press, then double press, hoping to see the numbers 1 to 15 displayed.  This what I saw:

14 Text Edit Numbers

The numbers were all printed out in order, so the combinations of short press, long press and double press all worked as predicted – but the long presses produced a continuous stream of outputs, even though I tried to take my finger off the button as quickly as possible.  The exception was the Centre button, which produced a single output of the number ’14’, no matter how long I held the button down.

This behaviour might not be what you require if, instead of printing numbers, you want a single specific action to be performed.  You might find the action repeated many times unless you’re able to take other steps to avoid this.

However, for testing purposes, this was fine, and I had established that the remote should, with iRedLite, be able to distinguish between 15 separate actions, despite only having 6 buttons.

*

The final stage of the project was to try out the new Tiny Touch Apple IR Remote to see if it would function correctly, using the iRedLite TextEdit Tester.

I quickly opened Joystick and Gamepad Tester to check the ID number of the new remote, which was 211.  I then opened iRedLite, went to the correct Layer for my Tester, and changed the remote number to which it would respond from 214 – the remote I had originally use to create the Layer – to 211.

The TouchPhone has a Power switch, but in fact the IR Remote worked even when it was in the ‘off’ position; in the ‘on’ position it worked with added lights.  As before, I pressed each button in turn with a short press, a long press and a double press, checking to see that the correct numbers were printed in Text Edit.

They were, so now it was safe to put the unit back together.  I glued the IR LED into the ‘antenna’:

top IMG_1580

fixed the 9-way socket in place:

bottom IMG_1584

and  wrote the ID number on the back.  Now I had the world’s most colourful Apple IR remote!  It could have been the world’s noisiest, had I not removed the speaker, but I felt this would be gilding the lily – and would probably have been a distraction, given that I had conceived of the remote as being part of a sound-modifying system, not a sound-producing system.

Alternative Remote

I was a little upset as, just as I was putting it back together, I broke the plastic link behind the ‘telephone’ button that mechanically ‘winds the film’ and changes the picture on the screen.  However, this only deprived me of more ways of turning LEDs on, and didn’t in any way affect the IR  controls, so ultimately I was satisfied with my achievement.  I didn’t want to spend more time on it at this stage as I wanted to move onto the next part of the IR project.

For this, see Part 3: Additions.

 

[Edit: I’ve since managed to get hold of another Tiny Touch Phone and replace the broken film winder, although I haven’t yet had time to change the tactile switch that got glued together].

15
Sep
13

The StyloSound

front_IMG_1497

The idea for the StyloSound came to me when, at about the same time, I acquired two small sound effect devices.  One was a ‘Sound Machine’, a small hand-held unit with 16 push-buttons, the other was a Sound effect kit with PCB, also with 16 different sounds.  I thought it would be a good idea to combine the two things into one unit and use the Stylophone stylus to trigger the sounds; plus I was also working on devices to interact with the ‘Bigfoot’ trigger/sequencer, so I decided to add the capability for the sounds to be triggered by the Bigfoot’s 4-bit binary output.

*

There are several varieties of Sound Machine.  The one I got was the silver ‘SciFi’ version.  This has a number of interesting ‘spacey’ effects, some of which I recognised from Star Wars, Close Encounters and others; some I didn’t.

sound-machine-sci-fi-box2

These Sound Machines aren’t all exactly the same inside, apparently (this site gives a very good first-hand account of looking inside them: http://www.magicmess.co.uk/cb/sm.php)*, but I guess the sounds are all initiated the same way – a +V pulse into the appropriate input of the dedicated chip which stores the samples.

*[Edit: unfortunately, this site is no longer up; I saved some of it, which had this information in it: http-www-magicmess-co-ukcbsm-php.pdf].

Having opened the Sound Machine and taken the PCB out, it was easy to attach a wire to each of the 16 inputs.  These wires went to the middle 16 notes on a Stylophone keyboard, salvaged from a broken instrument – via 16 SPDT switches, as I wanted to be able to choose either the sound from the Sound Machine or the sound from the Sound effect kit individually in each of the 16 positions.  This picture shows how the switches were arranged on the front of the StyloSound:

StyloSound outside in prep IMG_1469

The Stylophone stylus was connected to +V, and the output from the Sound Machine PCB went to the Stylophone speaker, which was much better than the small speaker in the original.

The Sound Machine is powered by three small 1.5v button cells, so it was no problem to use the Stylophone’s own battery compartment, which takes three AA batteries.  With all the switches to the left, the Sound Machine PCB was selected, and it was possible to play all 16 sounds from the Stylophone keyboard.  It was clearer from this than using the original buttons that each sound has to play right through before a new one can be selected.

The next obvious step was to interfere with the playback speed of the sample.  This version of the Sound Machine has only four visible components, two resistors and two capacitors – all tiny SMD (surface-mount) type – with the main chip embedded in its plastic blob.  Using the wetted finger method, I found the resistor responsible for playback speed, which is marked ‘R2’.  I removed it and replaced it with a potentiometer, which slowed down and speeded up the playback.

In this photograph you can see the points at which wires are soldered to the Sound Machine PCB.  In the magnified area you can just about make out the resistor on the left marked ‘R1’, the removed resistor, ‘R2’ (detached but still lying beside the place it was removed from), the wires going to the potentiometer and the two SMD capacitors behind the wires:

SMachine PCB IMG_1473

Unusually in my experience, the chip reacted badly to both too low a resistance and too high, and a 1M potentiometer, my usual first choice, was too big for it, causing it to crash.  In the end, I settled on a 470K potentiometer with 100k trimmers either side.  When the trimmers had been adjusted, this seemed to keep the resistance within acceptable levels.

(Later, I read the website referenced above, and the writer had a different solution to this problem, but I didn’t have time to check it out).

*

The above is all you would need to do to bend a Sound Machine, but the next thing in my case was to unpack the Sound Effect kit, which contained the following components:

Kit unpacked IMG_1471

The two logic chips are a 4066 (quad analog SPST switch), and 4011, (quad 2-input NAND gate); the sound effect chip was on a separate board, inserted, strangely, at right angles to the main board in the slot on the right.  The 4 SPDT switches enable the sound to be selected manually – the input is 4 bit binary – as an alternative to the 4 inputs on the left-hand side of the board.  Output is  through what looked like a small piezo element (the round black component in the bottom left of the picture).

The small board which the sound effect chip itself sits on is one of a range in the 9561 series.  This one has the prefix ‘LX’, but there are others, such  as ‘CK’, ‘CL’, ‘CW’, ‘KD” and others: all have the same general purpose, finding use in alarms, doorbells, and simple toys, making noises such as police sirens, machine guns and so on.  Simple circuits such as this one can be found on the internet utilising very few external components to produce the required sound (generally only one or two in each application):

LX9561

In fact, the kit I bought in an eBay auction only cost about the same as the module itself, and took full advantage of the range of sounds available by using the two switching terminals (F1 and F2) and a more complex array of resistors in place of the single 200k resistor shown in the circuit above.  The full list of sounds available is as follows:

0000: Machine gun voice
0001: Fire truck voice
0010: Ambulance voice
0011: The police car voice
0100: Crickets sound
0101: Alarm
0110: Electronic signal sound
0111: Koh
1000: Insect song
1001: Whistle
1010: Telegraph sound
1011: Bird song
1100: ChongJi gunfire
1101: Car sirens
1110: Bass instruments sound
1111: Racing sound

Some of these interpretations are rather fanciful, but that was no problem as I was more interested in making noise than repeating recognisable sounds.

This chart – for a similar chip in the series – gives some idea of the variations in binary inputs, combinations of selection inputs and resistances that produce different sounds.  If you read Chinese, which I don’t, it probably tells you in the right-hand column what sounds these combinations make.

KD9561 selection chart2

The PCB was robustly constructed and I put it together omitting the four slide switches, as I intended to control it externally, and didn’t attach the piezo sounder, which wasn’t going to be used.

Several of the resistors, when tested, had an effect on the pitch and speed of the sounds – the main job of the 4066 and 4011 is to select different combinations of resistors to affect the sound produced, much as indicated in the chart above – so I picked the likeliest one and replaced it with a 1M potentiometer.  This seemed to do the trick – perhaps taking things slightly too far in the upper direction, so I added a preset in series to keep it from going to its maximum – although it had happily done this without any danger of crashing the chip.

I only had a log potentiometer available, and in the end this was quite fortunate.  I found that connecting it the opposite way round from what would be expected – i.e. turning it clockwise decreased the pitch and speed, rather than increasing it – exploited the logarithmic scale well, making a much slower and smoother transition through the higher pitches and speeds.  I could have bought an ‘anti-log’ pot, but additional time and expense didn’t seem worth it.

This was a timely reminder that a useful part of experimentation would be to compare lin and log pots in particular situations, and reversing the log ones to see what difference this produced. (Reversing the linear ones would, of course, do no good, as they progress evenly through the scale from top to bottom, whichever way round they are).

This part of the circuit (the kit PCB) now looked like this:

Sound Effect Kit circuit 3

The original circuit diagram was provided by the supplier, Chip_Partner_Store, a Chinese company with an eBay shop at http://stores.ebay.com/Chip-Partner-Store.  Places like this – and there are many of them on eBay – are great for browsing through: you can find great deals on bulk buys of common components, as well as somewhat more unusual ones at very reasonable prices, and odd chips and modules like this one, which could always come in handy.

I’ve indicated in the diagram where I added the 1M potentiometer and preset, plus four LEDs, connected, via 470Ω resistors, to the A B C D inputs, the other ends connected to ground.  These were not there for any reason, particularly, except as an indicator of the code being received – and on the principle established with Bigfoot that flashing lights are always good.  I was sceptical as to whether the circuit supplying the four inputs would be able to power these as well as operate the Sound effect module correctly, but it all seemed OK.

The greyed-out section at the output wasn’t used in the final circuit.

Actually, this unit begins sounding repeatedly as soon as power is connected to it, since the default input 0 0 0 0 has an associated output – ‘Machine gun voice’ – and I couldn’t find a way of stopping it, so I also added a power on/off switch to this board, which isn’t shown, in case this feature became annoying.

*

SInce the circuit has four binary inputs, and I wanted to control the unit with the Bigfoot, which has a 4-bit binary output, it would seem logical to connect the Bigfoot output directly to the A B C D inputs.

Unfortunately, this wouldn’t allow the Sound effect module to be operated by the Stylophone keyboard, or the Bigfoot to control the Sound Machine, so additional circuitry was needed to convert the binary input into 16 individual outputs, and then convert that back into binary . . .

. . . Fortunately, the first of those would be a duplicate of part of the Bigfoot circuitry, which I was familiar with, using a 4067 chip.  This part of the circuit looked like this:

StyloSound - 4050_4067_3

The input from the 5-pin DIN socket goes first to a 4050 hex buffer.  Four of the six buffers are used.  The reason for doing this is to exploit an unusual and very useful feature which the 4050 shares with its more common sibling, the 4049.

Both perform a similar function, but the 4049 inverts the input (high level voltage in = low level voltage out, low level voltage in = high level voltage out), and the 4050 doesn’t.

What both of them are able to do is accept an input voltage level higher than the supply voltage, a vital consideration here as the output from Bigfoot is at 9v, whereas the circuitry of the StyloSound is at only 4.5v.  The 4050 is able to acccept the 9v input from Bigfoot and safely reduce it to 4.5v for the other circuits.  9v isn’t a problem for CMOS chips, but the Sound Machine and the Sound effects module are both rated at 4.5 – maybe 5 or 6 maximum – volts.

The four outputs of the 4050 go into the A B C D inputs of the 4067.  Each of the 16 outputs of the 4067 goes to the pole of one of the SPDT switches described earlier.  According to the binary coding on the inputs, one of the 16 outputs of the 4067 is connected to +V, and this signal is sent in the direction either of the Sound Machine when the switch is to the left, or the Sound effect module when it’s to the right.

*

The Sound Machine has 16 separate inputs, so no further circuitry was required: each switch was connected to one of the 16 places on the Sound Machine PCB where there used to be buttons.

For this signal to operate the Sound effect module, however, it needed to be changed back into binary.

Fortunately, this change is not difficult to implement, using a pair of 4532 chips and a 4071.  The 4532 is essentially the opposite of the 4067: it takes individual inputs and converts them to binary.  Each one has only 8 individual inputs and outputs in 3-bit binary, but the datasheet showed this 16-input, 4-bit binary output circuit, which is the one I used:

16 input encoder w pin Nos

The 16 inputs marked ‘From Stylophone Keyboard’ were all connected to ground with 100k resistors so that each one would be at 0v if not receiving a +V signal from the keyboard or the 4067.  The outputs of the 4071 were connected to the Sound effects module where marked A B C D in the earlier diagram.

Here’s how the physical connections are made, and what the chips look like on the board:

StyloSound 4532_4071_3

inside_IMG_1472_2

I’m not entirely sure that the correct order of those 16 inputs is as implied in the datasheet circuit.  Since I had LEDs on the inputs of the Sound effects module – i.e. effectively at the outputs of the 4071, I was able to check the sequence, and I found myself swapping some of them around.  If you’re using this method of converting single outputs to binary, it would be advisable to check this as you go along.  In my case, the wiring to and from the SPST switches was such a bird’s nest, that it became too difficult to work this out.  If it becomes clearer when I use this system in future projects, I’ll make sure to record the correct sequence.

However, when tested with ‘Bigfoot’, the module was triggered accurately, and the LEDs on the input lit up with the correct numbers when the notes were tested with the stylus and keyboard.

*

So now I had two separate sound effect circuits which differed in several ways: the Sound Machine uses samples, which are played back in their entirety, and are particularly effective when slowed down; the Sound effects module produces electronic sounds from oscillators, which can be cut off and replaced at any time by another sound, and lend themselves to being sped up.

Both sections had separate pitch/speed controls; both could be controlled automatically by Bigfoot, or manually via the Stylophone keyboard.

*

I could have stopped there, but I had another idea which I thought could be included.  I believe this is known in the trade as ‘feature creep’ – just adding that one extra implementation, which then turns into two, then three . . . and eventually makes a simple circuit over-complicated.

But I had  just acquired a number of unwanted ‘Voice Recorder’ key rings – 100, in fact! – at a few pence each.  At this price, they weren’t guaranteed to work, but when I tested some, quite a few seemed OK, and they were powered by 3 little coin cells – i.e. 4.5v, the same as the rest of the circuits in the StyloSound, so I thought I could employ a couple of them here.

Here’s what they look like:

outside_inside

There’s a very small microphone, a Record/Play switch, a button to operate whichever of the two functions it’s switched to, and an LED to indicate that it’s recording, as opposed to playing back.  I thought it would be good to be able to record a small (up to 8.2 seconds, it said) burst of sound while the samples or effects were being manipulated, then be able to play it back precisely the same again, a primitive – but undeniably inexpensive – repeat/looping device.

So I added a couple of these, connected to the outputs of the Sound Machine and the Sound effect module.  Small tactile switches glued to the front of the instrument replaced the ‘Record/Play’ switch and button, and I also moved the small LED’s to the front panel as well.

*

Only one thing remained, as far as the circuit was concerned, which was the output stage.  This turned out to be . . . strange.

First of all, I needed to mix together the four outputs: the Sound Machine, the Sound Effects module and the two recording devices, as well as send the Sound Machine and Sound Effects module outputs to the inputs of the recorders.  I planned to do this  with a passive mixer – i.e. just join the outputs together with resistors.

The Sound Machine worked perfectly with the internal speaker, but the Sound Effects module would only work with the other speaker terminal connected to +V rather than 0v: otherwise, it was extremely quiet.  I got round this by taking the output directly from the output of the LX9561 board, as indicated in the circuit diagram above, and bypassing the output transistor.

The outputs of the recorders were much too quiet, too, and the only way I could make them loud enough was to give them a path to +V by means of a very low value resistor (22Ω).  The sound quality of these didn’t quite match that of the Sound Machine and Effects module – partly, no doubt, because of reduced bandwidth in the recorders – but they definitely added a useful function.

In fact, I had intended to add tone and volume controls at this point, but the device refused point-blank to make any sound if anything other than a very low value resistor was put in the output path, I don’t know why.

In the end, I used 22Ω resistors to join the 4 outputs (two in series for the Sound Machine, which was a little louder than the others) and ran this straight to the speaker and output socket.  So, the final stage looked like this:

StyloSound - Output_3

The resistors are all 22Ω, as opposed to some other equally low value, simply because I had a pile of them which were going spare.

So: strange, but when I plugged it into my mixer, it  sounded fine, and the volume could be adjusted there.

*

The only thing left to do was to finish the case.  There was so much internal wiring and circuitry that the case had to be made 2.5″ deeper.  I constructed sides from an offcut piece of white plastic and superglued them in place – not especially neatly, it has to be said – with a little internal bracing.

top_IMG_1498
rside2_IMG_1494
back_IMG_1493*
This is what the StyloSound sounds like, controlled by ‘Bigfoot’:
19
Apr
13

UCreate Music, Part 1

This post concerns a very interesting device which was made a few years ago by Radica, a Mattel company.  It was manufactured for a very short time between 2009 and 2010, and supported only until 2011, but examples still appear on eBay, sometimes for very reasonable prices. I got mine for less than £10, which I thought was pretty good for a comparatively sophisticated machine.

ucreate box

Front low angle IMG_1320 Edit

The way it works is by playing loops, which you can choose from its memory – one each from 4 banks of 3 loops, in the categories ‘Back Beats’, ‘Riffs’, ‘Licks’ and ‘Runs’ – and apply effects to.  You can also record two of your own samples to add into the mix.

This is how you would normally use it (ignore the toggle switch and sockets on the left-hand side: this and other modifications I made are described later):

Controls IMG_1319

There are two reasons why the UCreate captured the imagination of electronic music-makers.  First of all, you could connect it to your home computer via a USB socket on the back and make use of software that would allow you to save recordings of songs, reorganise the loops and effects and download new loops from Mattel’s UCreate website.  I’ll return to this topic later.

The second thing was the range of 8 special effects, and the fact that these are available not only to the loops played back by the UCreate, but also to any audio source connected to the Mic or  Line in sockets.  The effects – referred to as ‘FX and Filters’ – comprise Tremolo, Distortion, Flanger, Phaser and Echo, a variable low-pass filter, and two unique and unusual effects called Forward/Reverse Looper and Rewind Spin Looper.  These work by recording very short samples and replaying them in various ways controlled by the user.

The way the effects are controlled is also highly unusual:  a large Button on the front panel can be pushed and tilted left/right and up/down to vary two parameters of the effect – for example left/right controls the speed of the flanger, up/down controls the depth.  If you find a setting you want to leave for a while, a ‘Hold’ button fixes it where you’ve set it until ‘Hold’ is pressed again.  The fact that the whole Button is lit up when in use  with flashing blue LEDs is just the icing on the cake.

Leaving aside the loop playback feature for the moment, this effectively makes the UCreate an inexpensive, but versatile multi-effects unit, playable in real time.  Although only one of the effects is available at a time, the Forward/Reverse Looper and Rewind Spin Looper in particular, together with the ability to control these in real time with the Big Button, makes the UCreate a useful and unconventional device to have.

I began by using the UCreate in this way, making just a couple of small modifications to it.

First, I added a socket for an external power source; then, as I had done with a number of my other instruments, I added banana sockets for connecting a larger external 8ohm speaker and a DPDT switch to cut out the internal speaker when this is in use.  There is a headphone/external speaker socket on the back of the Ucreate (which also cuts out the internal speaker when a plug is inserted), but this is a 3.5mm stereo socket, as you would find on a PC or mp3 player and is more suitable for use as a Line out.

These are the audio and USB sockets on the back of the device:

Rear sockets IMG_1358

Next, imagining a situation when both hands might be occupied in operating the loops and effects and not able to control the volume, I added a socket for an external volume pedal.  This was a 3.5mm stereo socket with internal switches, like the Line out socket.  I used a small size socket purely because of the lack of space inside the case.

On the small circuit board attached to the on/off/volume control, I broke the connection to the centre of the volume potentiometer and rewired it to the socket so that when nothing was plugged into it, it was connected directly to the main Ucreate circuit board, as originally designed; when the volume pedal was plugged in, the potentiometer in the volume pedal was added into the circuit.  This would enable the maximum volume to be set by the original volume control and the pedal to move between this and zero volume.

The pedal itself was simply a cheap second-hand Bespeco volume pedal.  I removed the original sockets and the circuit board inside and connected the potentiometer to a 3.5mm socket, wired in a similar way to the socket inside the Ucreate.  The tip was connected to the input from the Ucreate and the ‘high’ end of the potentiometer in the pedal, the sleeve to Ground and the ‘low’ end of the potentiometer, and the ring to the potentiometer wiper, the centre tag. (I should have built this before, as it would have been useful with many of the instruments I had made or modified, and I’ll have to consider retro-fitting sockets to them so it can be used).

Vol Pedal IMG_1326

I then decided to take a closer look at the big control Button.  I tried dismantling the mechanism, but couldn’t seem to get it completely apart.  This may have been because it was pressed or glued together after the circuit board was wired in, and I wasn’t going to risk breaking it by trying to prise it apart if it wasn’t meant to do that.

Button partial dissassembly IMG_1328

However, I got it apart far enough to see that it used a joystick for the left and right and up down movement.  This was mounted on a small PCB, and on the bottom of the PCB there were three momentary switches, set out in a triangle.  These were like the ones you often get on game controllers: they’re soft and squishy, and when you press them they join two contacts on the PCB; when you take your finger off, they spring back into shape and the connection is broken.

Button circuit board IMG_1333

All three switches were connected the same, and later experimentation showed that they had exactly the same function as the ‘Hold’ button, except they were momentary instead of latching.

This gave me two thoughts: first of all, with essentially a joystick and a momentary switch under it, it would be possible to use the UCreate’s Big Button to control another instrument or effect that normally used a joystick or two separate potentiometers; and secondly, there was no reason why the UCreate couldn’t be controlled by two potentiometers or an external joystick.

The way to do this would be to put the Button back and separate the connection between the UCreate’s main PCB and the Button PCB, and then route these connections elsewhere.

The link was made with a 9 way ribbon cable; the names of these 9 connections were printed on the main PCB, and even where this didn’t mean a lot, it was easy to follow the the tracks on the Button PCB and see what their functions were.  So I cut the cable.

From top to bottom, the connections were:

VCC_33 – which connected to one side of all three switches

IOA15 – connected to the other side of the three switches

GND_ADCVCC33 – connected to one end of the two joystick potentiometers (the ‘low’ end, presumably)

LINE 3 – the centre tag of one of the potentiometers (the ‘up/down’ one, which I called ‘Pot 2’)

ADCPVCC33 – the other end (‘high’ end) of both potentiometers

LINE 2 – the centre tag of the other (‘left/right’) potentimeter which I called ‘Pot 1’

R154_1 – one side of one of pair of surface-mounted blue LEDs on the Button PCB

R68_1 – one side of the other LED

V BAT – the other side of both LEDs (+6v, presumably)

Essentially what I did was to connect the end of the ribbon cable that came from the main PCB directly to a DB9 connector on the back on the case.  This was marked ‘In’.  The other end of the ribbon cable, the one from the Button PCB, was connected to another DB9 connector, marked ‘Out’.

In this way, if you wanted to control the UCreate from another device – a larger joystick, perhaps – all you would need to do was connect it to the DB9 ‘In’ socket; if you wanted to control another device with the Big Button, you would connect the other device to the DB9 ‘Out’ socket; and to use the UCreate as normal, just connect the two sockets together with a DB9 cable.

In order to make space for the DB9 sockets, which are quite big, I had to remove part of the bottom half of the case, which stuck up inside:

Inside sawing IMG_1341

I think this was probably a carrying handle, but I didn’t think I needed it, so I sawed it off and created a lot more space in the back of the case.

In fact, I didn’t connect the Button directly to the ‘Out’ socket.  Although the Button works brilliantly well for the Reverse and Rewind ‘stuttering’ or ‘scratching’ effects, there was a lack of precision when it came to such things as the filter cut-off frequency, speed and depth of flanging, and so forth.  Apart from anything else, joysticks don’t usually use much of the possible travel of  an ordinary potentiometer, so there was also a restricted range over which the Button was operating.

So I decide to squeeze a couple of potentiometers into the case, which would be selectable in place of the Button.  The two connections for the centre tags of the potentiometers (‘Line 2’ and ‘Line 3’)  coming from the Button PCB went to one side of a DPDT switch, and the poles went to the DB9 ‘Out’ socket.  The wires from the other side of the DPDT switch went to the centre tags of two potentiometers, which I squeezed in the front of the case.  The two connections for the ends of the potentiometers went to the potentiometers and to the socket.

In the event, I also added a 10k preset, set at about halfway, in the circuit at the potentometers’ ‘bottom’ end: it seemed to me that some parameters – e.g. the filter cut-off frequency, and the volume pot when using the tremolo effect – were going too low, at the expense of effects that could be obtained with higher resistance.

The way the UCreate works, the potentiometers  – and the potentiometers under the Button, come to that – have no effect unless one of the ‘Hold’ buttons is pressed, so I needed to add a momentary button, preferably somewhere near the potentiometers.  There was just about room, and what I decided to use was a toggle switch with a centre off position, momentary on in one direction, latching on in the other.  This would enable me to engage the momentary switch, adjust a potentiometer, then when I had exactly the sound I wanted, latch the switch on.  So the two connections for the switch went both to the DB9 socket and to this new switch.

In fact, they went to a third place: a standard (1/4″ or 6.35mm) mono jack socket to which a ‘Hold’ footswitch could be attached.  I used a standard size jack in this instance because I had some nice ready-made footswitches: they’re apparently sold for use with tattoo machines, but come with standard jacks attached, which is very handy.

Hold Pedal IMG_1356

So that’s how I modified my UCreate, producing a versatile and quite easy to use multi-effects device.  This picture summarises most of the changes I made:

Inside closeup w. captions IMG_1346

I don’t know if they’re all the same, but the grille on the front of mine came off very easily, so I took the opportunity to remind myself of what the 8 effects are, and what order they come in.

Front grille off IMG_1324

The front and back of the device now look like this:

Front and back IMG_1352

and here’s what it looks like in operation:

In operation 2 IMG_1348

Read the UCreate User Manual here: N9496 UCreate Music Manual 1L-English

In Part 2 of this series of articles I describe modifications made to some other devices in order to work with the UCreate.

23
Aug
12

BigBoy BeatBox

You’ve got a Stylophone, you’ve got a Stylophone Beatbox – but don’t you sometimes wish the two could be combined into one instrument? . . .

Well, now that wish has become reality, with the ‘BigBoy BeatBox’: two great Stylophone products in one!

New Front IMG_1128

As the picture suggests, the BigBoy BeatBox is, in fact, two great Stylophone products literally glued and bolted together, with some of their internal circuitry combined.  The way it was created was like this:

1.  The Stylophone

The Stylophone half of the instrument is, in fact, a recreation of the original ‘Big Boy’ – a regular Stylophone S1 inside a Beatbox case.  As mentioned in an edit to the original post here, I managed to inflict terminal damage on the ‘Big Boy’ by reckless experimentation.  I normally do this before finishing an instrument, this time I contrived to do it afterwards . . . so the first thing I had to do was remove and replace the electronics with a new donor Stylophone I had lying around.

The actual process closely followed the construction of the original, but was made easier because of the sockets and wiring still remaining in the Beatbox case.  First of all, the end had to be sawn off the Stylophone circuit board, which is too long to fit in a Beatbox case; then the lowest 12 notes of the keyboard were connected to the 12 outside pads of the round Beatbox keyboard.  Fortunately, the wires attached to the Beatbox keyboard remained in the case, and just needed connecting to the appropriate Stylophone keys.  The Beatbox’s amp circuit board was taken out, but the Stylophone’s was kept and connected to the Beatbox’s speaker.  A power socket was connected to the Beatbox’s on/off switch, and the Stylophone’s on/off and vibrato switch circuit board disconnected.

I decided to replace the ‘Big Boy’s troublesome original 3-way octave switch with a simple  pitch potentiometer.  I used a 100k for  coarse tuning, in series with a 10k for fine tuning and a 100k variable preset to fix the highest pitch available.  Previous experimentation with Stylophones had taught me they have no objection to going down to very low pitches, but they cease to function – usually temporarily – if the pitch is taken up too high: on resetting, when this happens – by switching the power off and on – sometimes they will begin to work again, sometimes they won’t.

That’s what I did to the original ‘Big Boy’, and there’s no cure apart from throwing the circuit board away and starting again.  The likelihood of this happening is increased because I don’t just replace the tuning potentiometer pin-for-pin – the range of voltages available between the two pins the Stylophone uses isn’t wide enough for very large pitch variations, so I use only one of the pins that the original tuning potentiometer was connected to – the left-hand one – but connect the other one to +v.

The two new pitch controls were fixed to the front (the rounded end) of the Beatbox case, as was a replacement 10k log volume control.  The problem with the Stylophone’s original volume control was not that it wouldn’t work perfectly well, but that it would have had to be on the side of the case which I was intending to fix permanently to  the other Beatbox.

The original ‘Big Boy’ had no vibrato, but I decided the recreation should have a variable control, as fitted to the ‘Alien’, my first Stylophone modification project.  All this involved was connecting a 1M potentiometer instead of an on/of switch between the two vibrato connections next to the power connection on the main Stylophone circuit board.

Apart from an output socket and a switch to cut out the internal speaker, that half of the BigBoy BeatBox was done.

Stylophone half IMG_1132

2.  The Beatbox

The other half of the instrument was a plain Beatbox, with very little in the way of modifications.

(I don’t seem to have written specifically about the Beatbox in the blog, by the way.  Read the user guide here!)

The first thing I did to it was to replace the tuning potentiometer with a larger one of 100k (a direct pin-for-pin replacement this time), allowing for considerable slowing down and lowering of the pitch of the drums and other sounds.

I also followed an excellent example in this YouTube video: http://www.youtube.com/watch?v=xXdelnxXF7A to add buttons in parallel with the ‘Record’ and ‘Play’ pads normally operated by the stylus.  The trouble with the stylus-operated method is the delay in time between activating ‘Record’ with the stylus, and then using the same stylus to stop recording and begin playing the pattern you want to  be looped, as the loop begins the moment ‘Rec’ is selected.  With a small normally-open tactile switch as an alternative method of beginning and ending the recording period, you can be much more accurate as regards timing.

It’s worth mentioning at this point that, like the original Stylophone itself, the Beatbox comes in more than one variety, as far as circuitry is concerned.  I noticed two significant variations between the Beatbox I used in my ‘test to destruction’ phase, and the one that eventually found its way into the finished instrument: in one case, there was a tap from the battery compartment at 3v, which fed into the circuit (via the 3-way tone control) as well as the full 4.5v; and the layout of the circuit board was different.  As it happens, spots on the board marked ‘Rec’ and ‘Play’ were easily accessed in one case – the test unit – but not in the other – the one I was eventually to use.

In my experience, the Beatbox is a very delicate circuit, and it doesn’t take much to do something to it that will cause Record or Play to malfunction, or the output quality of the sound samples to degrade; so, proceed with caution, I’d say.

A third new button I added to this unit was ‘Reset’.  The Beatbox’s method of erasing an old loop and re-recording a new one is to switch the power off and on again.  The original power switch had to be removed as it was on the side of the case which was going to be fixed to the other Beatbox case – and there would, anyway, be a single power switch for both units: so the third button is a direct replacement for the Beatbox power switch, but now a normally-on, push-to-break, supplying power to the Beatbox side only.  To reset and re-record just takes a quick press and release of this button.

Finally, a new 10k log output volume pot was fixed to the front of the unit.

Beatbox controls IMG_1131

Beatbox halfIMG_1131

3  Joining the two halves

Superglue and two bolts was all that was required to physically join the two Beatbox cases, plus a couple of holes through which wires could pass from one side to the other.

The easiest way to connect the power seemed to be to detach the +v and 0v wires from the battery compartment on the Beatbox side and attach these to the original ‘Big Boy’ Stylophone side, which had a power input socket.

In the end I decided that whereas the battery compartment of the Big Boy Stylophone had to be removed – there was no room for batteries as well as the Stylophone circuitry – the one in the Beatbox could be used.  So I wired in a power cable which ran out of the back and was just long enough to reach the power socket in the other half.  In this way the instrument could be powered from an external source, or from internal batteries, and there was no need for a switch to change from one to the other.

The two 10k volume controls were taken to two individual tone controls.  I just wanted something fairly rudimentary, so I used a circuit from http://www.muzique.com/lab/swtc.htm called the ‘Stupidly Wonderful Tone Control’.  The component values I used were quite different – and I have no idea why – but the format of the circuit was more or less the same, and gave a little bit of variation to the tone.

After the tone controls, the two outputs were joined with 10k resistors to the original Beatbox volume control, and then the ‘Big Boy’ Stylophone amp circuit board.  This meant that the sound from both units was going to the ‘Big Boy’ half , and the volume and tone of each unit could be independently varied.  The input to the Beatbox amplifier was disconnected, and the speaker removed.

Now I had an instrument in a single conjoined case, with a single power supply and output through a single speaker or output socket.  There were two styluses and two keyboards, and – as I had hoped, but not expected with any confidence – both styluses work on both keyboards!  This means that both units can be played with a stylus in each hand, and quicker and more rhythmic patterns can be played.  I extended the wires to the styluses slightly to make sure they could reach right across both keyboards.

When using two styluses on the ‘Stylophone’ side of the unit, the ‘Beatbox’ side needs to be set to ‘Play’, otherwise that stylus will only work for a very short period and then not sound any more.  I haven’t timed the ‘very short period’, which might give a clue, but this is probably to do with the circuitry which regulates the maximum of 8 seconds (at ‘normal’ tempo) for which the Beatbox can record.

The complete circuit looks something like this:

BigBoy Beatbox circuit 2 Corrected sm

The following pictures show the inside of the instrument shortly before it was finished:

Inside Stylophone half with numbers 6 in IMG_1127

This is the ‘Big Boy’ stylophone half.

1 = speaker cutout switch

2 = socket for external 4.5v power source

3 = 3.5mm sound output socket

4 = Stylophone S1 circuit board with permanently soldered connections to first 12 keys

5 = socket for extra stylus, remaining from original ‘Big Boy’ design – not really needed now

6 = fine tune pitch control

7 = variable preset to prevent the Stylophone’s highest note from being too high and causing the circuit to malfunction

8 = coarse pitch control

9 = Stylophone volume control

Beatbox half with numbers 7 in IMG_1126

This the Beatbox half.

1 = the original Beatbox output and ‘mp3’ input sockets, no longer used

2 = Stylophone tone control

3 = Beatbox tone control

4 = Original Beatbox volume control, now master volume

5 = ‘Reset’, push to break switch

6 = wires going to ‘Play’ and ‘Record’ push to make switches mounted on top surface of Beatbox

7 = original Beatbox tempo switch, still in-circuit, but no longer used

8 = Beatbox pitch control

9 = Beatbox volume control

The features visible on the outside were these:

Front DSCF0003 3

Before finishing I gave the speaker grilles a coat of blackboard paint.  The reason I used blackboard paint was a) it was the only black paint I found in my garage not in a spray can, and 2) it gives a pleasing matt finish, but is more durable than water-based matt emulsion.

The rear of the instrument was sprayed black and the holes masked with painted material.

New Back IMG_1130Front & Rear View IMG_1129_30

08
Jun
12

Bits & Pieces 4

I wasn’t expecting to add this post just yet, but I had a stroke of luck which has enabled me to complete the scheme for my mono mixing section which I started writing about when I described the Red Dragon the other day.

I bought a job lot of small SoundLab mixers off eBay which were said to be faulty returns.  I thought I might be able to salvage some parts from them, use bits of them in some way, or even repair them – but it turned out that several of them appeared to be in working order.

Two of them were straightforward 4 channel mono mixers – an updated version of the one I had used before, I presume – so these were immediately used for the left and right channel inputs to the mono mixer, as I described in the previous post.  Generally speaking, I wanted to have the lower tones to the left and higher tones to the right, so my ‘double bass’ stylophone was the first thing to be plugged into the left mixer; the treble stylophone and the SoftPot Stylophone in the right.

4 Mixerssm

More interestingly, the two other working units were the G105C version with ‘microphone effects’ – a delay circuit which I guessed was probably based on a PT2399.  I opened up one of the dead ones, and found that this was the case.

The circuitry was very different from the original SoundLab mixer I’d acquired – all surface-mount components; everything, pots and sockets included, firmly fixed to a single circuit board – and I’m not sufficiently skilled or equipped to be able to repair something like that.  Not only was it not functioning, it seemed to short out the power when the on switch was pressed.

I sawed out the part of the circuit with the PT2399 on it, which didn’t short the power when used by itself, but didn’t do anything to the input sound either.  This section is permanently in circuit when the mixer is operating, so maybe that was why the original unit didn’t work.  In any event, I decided to put the broken ones away for another day, and concentrate on the ones that worked.  The case would find a use later on.

First of all an echo unit is a really useful thing to have – and 2 echo units with 4 inputs is a bonus!

My initial arrangement with these is to have the outputs connected to the new Left and Right Mixers.  The left echo unit is used for instrument input and the output is divided: one half of the output going directly to the Left Mixer, the other half going to the right echo unit, and from there to the Right Mixer.  As the delay time and feedback (number or length of repeats) are separately adjustable on the two units, some interesting stereo effects are possible.

16
May
12

Bits & Pieces 2

This Bits and Pieces post is about mixers.  There is nothing inherently new or exciting in my system, which isn’t complete yet, but it’s building up to something more interesting in the latter stages.

The part I’ve been working on is the section for mono instruments, which works like this:

First of all I started with a small 4-channel mono in-mono out Soundlab Micromixer for £6 or £7 on eBay.

Fortunately, this came with a circuit diagram, so it was easy to add 4 more identical input channels.  These are housed in the ‘Red Dragon’, a Stylophone case from which the innards had been removed (for use, I think, in The Gemini, which is two Stylophone circuits in one body).

Red Dragon_Mixer bonnet 2 IMG_0917

The Red Dragon feeds the Micromixer with 9v power as well as the 4 extra input channels (the ones with red caps).  But I like working in stereo, so the 4 extra inputs are switchable from mono to stereo: the stereo side of the switch sends the input via a passive mixer (a 10k resistor on each channel) into the input of a pseudo-stereo circuit, and from there to a stereo output socket.

I’ve lost the circuit diagram and explanation of the pseudo-stereo circuit, but it was published in an electronics magazine in the 1980’s, and I bought and made up a kit version from them.  It may even have been the work of the amazingly prolific RA Penfold.  At the time I used it to listen to mono cassette tapes on my Walkman, and it improved them no end.  An empty cassette box was just big enough for the circuit board, headphone socket and PP3 battery; it was still in this box when I recently found it, and needed only a replacement 741 op-amp, which had evidently been scavenged at some point in the past.

I don’t remember precisely how it works, but it seems to be some sort of frequency-dependent phase-shifter, whereby some frequencies are sent to the left ear, some to the right, spreading a single mono signal throughout the stereo field: perfect for sounds with a rich harmonic content – like the Stylophone, for example.  (Mono instruments The Alien and The Hedgehog are ideal candidates for this treatment).  Which one of the channels is ‘left’ and which is ‘right’ using this system seemed entirely arbitrary to me, so I added a switch to reverse the output channels, according to taste.

In fact, there was room for two more input channel pots on the top of the Stylophone case, but no room for the switches and circuitry beneath, so these two channels (the ones with blue caps) go directly into the passive mixer and pseudo-stereo.

While the stereo signal currently goes directly to a stereo in-stereo out mixer, the mono output goes to a 6-channel mono in-stereo out mixer (a Realistic 32-1210, £10 off eBay) .  This has a balance control on each channel, so the intention is that the section described here will be the centre channel, and there will be further sub-sections for left and right parts of the stereo field.  Later posts will indicate how this works out.

The stereo in-stereo out mixer (£6 off eBay) is a Hama SM502.  Although the inputs of this mixer are marked ‘Microphone’, ‘Magnetic/Ceramic cartridge’, ‘Phono’ and ‘Tape’ (i.e. it’s a mixer intended for a domestic hi-fi!) experiments have shown that they work fine with the signal levels involved here.

Red Dragon_Mixer bonnet 1 IMG_0916

16
May
12

The SoftPot Stylophone

Ever since I found out about the ‘SoftPot’, I wanted to use one to control a stylophone.

A SoftPot, if you’ve never come across one, is a type of slider potentiometer – but not a metal one with a knob, like a fader on a mixer: it’s a wafer-thin piece of flexible plastic, and you operate it by pressing on it with your finger, or an ‘actuator’ – something like a pen will do, but it’s better if it has a rounded end not a pointed one, as that won’t damage the thin plastic. It looks like this:

softpot1

(This is one which still has its backing sheet.  The SoftPot itself is transparent, and sticky on the back).

The normal SoftPot value is 10k. When I looked at stylophone circuits, I realised that in most cases 10k isn’t going to do much. The pitch pot I added to The Alien – a modern reissue stylophone – was 2.2M, and although that amount of variation in pitch wouldn’t really be necessary, 10k would only represent a few notes.

So I looked at one of the original 1970s stylophones, and saw more possibilities there, so I bought one from eBay with a slightly damaged keyboard.

The definitive guide to the sounds and circuitry of the original stylophone is at http://www.waitingforfriday.com/index.php/Reverse_Engineering_the_Stylophone, but the particular circuit variation of the one I had was not quite the same as the one they had. The circuit of mine was like this:

Original Stylophone circuit

The values of the resistors are a bit blurry in this scan, but you can see that 10k isn’t going to affect the pitch very much if connected to the resistor ladder on the left – along most of the scale, this would represent only about 2 or 3 semitones.

So I concentrated on the area where there is a tuning pot and a resistor to +v and resistor to ground. The tuning pot, which was 25k, allows the stylophone to be tuned, but doesn’t really cover more than about half an octave – still not enough to play tunes effectively.

At first, I tried varying the 470Ω resistor to +V and the 820Ω resistor to ground, but to little effect: adding a 1k variable resistor to the +V end, in series with the 470Ω, and turning it down a bit did seem to help, but in the end the effect I wanted to achieve – a variation between top and bottom of a couple of octaves – was achieved first of all by reducing the tuning pot value to 10k, the magic number, the same value as the SoftPot.

Secondly, the stylophone version I was working on had a resistor in parallel with the tuning pot – a very small one of about 270Ω. Replacing this with a resistance of 1k seemed to do the trick – and in fact I added a 1k potentiometer, as this would function as a narrow-to-wide control of the note range, in tandem with the 10k tuning pot.

A 3.5mm stereo switched socket on the side of the stylophone would allow the stylophone to function normally, when required, but anything plugged into the socket would replace the tuning potentiometer in the circuit. This is how the SoftPot would be attached.

That part of the circuit now looked like this:

SoftPot Stylophone 2

and the SoftPot Stylophone looked like this:

SoftPot Stylophone right high angle IMG_0906SoftPot stylophone back corner IMG_0907

The next thing was to make a unit for the SoftPot which could be plugged in when required. This was quite a minimalist design, and was put together like this:

SoftPot Stylophone 4

The SoftPot, as previously mentioned, is sticky on the back, so was stuck to a piece of 2mm acrylic sheet cut to fit on top of the keyboard, just clear of the power and vibrato switches, and nestling inside the lip on the right hand side. Underneath this was stuck a smaller piece of 2mm acrylic which fitted inside the keyboard cut-out, and stopped the whole thing from moving as it was played.  These three layers were stuck together, but weren’t stuck down to the keyboard.

The soft pot terminals came attached to a 3 pin socket, the same size as the ones you get for PCB headers. I had some of these, so made up a lead with a 3.5mm stereo plug on one end, and a 3-pin PCB header plug on the other.

SoftPot attachment 2 IMG_0903

You may be able to see from the back of the attachment how it was put together to fit firmly into the keyboard recess:

SoftPot Stylophone w back of attachment IMG_0908

The SoftPot assembly fitted in place, and was ready to go. All it needed was an actuator – like a pen, but with a rounded end. And, of course, the stylophone has one of these already: the stylus which gives it its name! So the SoftPot Stylophone can still be played with the stylus in the traditional manner, but moving up and down the SoftPot, like a ribbon controller.

SoftPot Stylophone Complete high angle IMG_0909

There was just one more change to make to the circuit before this could happen. The Stylophone sounds when the +V in the stylus contacts a key, which is in turn connected somewhere within the resistor ladder. Now that the keys had been covered up, there would be no sound without a connection between the resistor ladder and +V – the stylus only pushes the SoftPot together, and the connection is made internally.

As with The Alien and The Hedgehog, I simply made an internal connection between +V and one of the resistors in the ladder – the highest note – operated by closing a switch. Try as I might, I couldn’t arrive at a situation where the SoftPot Stylophone was silent until the Softpot was activated, but still gave a good note range.  So I added a volume control – a feature which any stylophone would benefit from – and when you play, you can turn the volume down when not sounding a note with the SoftPot.

Before finishing up, I added a socket to allow the SoftPot Stylophone to be operated from an external power source, a switch to cut out the internal speaker (this is not done automatically when the lineout socket is used), and a switch to cut out the low-pass filter in the line-out circuit.

These original stylophones are famous for having a simple resistor-capacitor tone control on the line-out circuit which is not in the circuit to the internal speaker. This is the main reason why stylophones sound so different when the line-out socket is used. When you see pop musicians who use the stylophone at live gigs holding their instrument up to the vocal mic as they play, this is not mere theatricality: it is theatricality, of course, but it’s also the only way to get an unmodified stylophone to sound the same to a stadium or festival audience as it does to you when you play it ‘unplugged’ at home.

The other end of the circuit now looked like this:

SoftPot Stylophone 1

Finally, I made a small modification for the benefit of a future project which I haven’t yet started on. I added another 3.5mm stereo socket configured in a similar way to the SoftPot input socket. In normal or SoftPot operation the resistor ladder is connected into the circuit; but anything plugged into this socket replaces the resistor ladder.

IMG_0912

31
Dec
11

Stylophones

I must say I’m very fond of Stylophones!

The Stylophone, if you’ve never encountered one, is a small, hand-held monophonic instrument played by touching a stylus to a row of metal pads – the edge of a large printed circuit board – laid out like the keys of a piano. It was invented and first marketed in the 1960s, and is sometimes described as the world’s first mass-produced synthesizer.

In my view the Stylophone is an indispensable element in the arsenal of the electronic musician – it’s simple, distinctive-sounding, and most types are available at a reasonable price, with patience, from charity shops or on eBay. It’s also possible to make a number of straightforward – and some not-so-straightforward – modifications to it. I have described elsewhere in the blog some of the ones I’ve done.

Although largely the brainchild of engineer Brian Jarvis, accounts of its genesis in 1967 suggest that the Stylophone would never have seen the light of day without the encouragement and input of brothers Burt and Ted Coleman who, together with Jarvis, ran a company called Dübreq. Dübreq produced equipment for the film and broadcasting industry and their name is said to derive from their specialities of DUBbing and RECording, with the umlaut and the ‘q’ added to give the firm more of an international air (or perhaps, like Motörhead or Mötley Crüe, just to look cool!)

The marketing masterstroke which ensured the eternal popularity of the Stylophone was the engagement of the multi-talented London-based, but Australian-born entertainer, Rolf Harris. Even before production began, the Stylophone was introduced to the world on Harris’s popular Saturday TV show on the BBC, and, it is said, became an instant hit – despite at first being available only by mail-order from Dübreq at the frightening cost of 8 pounds 18 shillings and sixpence, around ninety-five pounds in today’s money!

Over the following decade a number of different versions of the Stylophone were produced. I have a treble – which is all white – a standard black, and a bass – also black. This latter wasn’t a production model, but the circuit diagram that came with the standard showed different component values for all these three types, so I modified a standard to produce the bass register, an octave below. I’ve subsequently modified this to produce a further octave below that – I call it ‘The Double Bass’ – but this is not a modification suggested by Dübreq themselves.

This is a circuit diagram of an early Stylophone. Note the details of alternative components: resistors in the top left and capacitors in the bottom left.

Stylophone schematic 2

There is also a later 1970’s version (the ‘New Sound’) with a fake wood fascia in place of the familiar metal grille. This latter has a feature noticeably absent from the earlier models – a volume control, a useful feature in the days before the ubiquitous earphones. Here is the component layout and schematic/circuit diagram from the booklet which came with it.

Layout and Circuit Diagram

It was not long after this, in 1975 or thereabouts, when production of the original Stylophone ceased; and this might have been the end of the Stylophone story, had Brian Jarvis’s son Ben not had the idea in the early 2000s of bringing it back. By 2007 the new Stylophone S1 was on sale, sufficiently similar to the original to be instantly recognisable, but with some updated features, including built-in input and output sockets and a three-way tone control.

Stylophone S1 2sm

It’s possible to do modifications on all these variations on the Stylophone design, even the S1. Despite the fact that the chip that does all the work in the S1 is very tiny and inaccessible, parts of the pitch and vibrato circuits are available, and the output stage is on a separate PCB. I was able to do some mods on a couple of these.

The ‘New Sound’, based on the very common 555 chip is easier to deal with, and I was able to do a lot with mine (see http://wp.me/p25FoK-10). There are many circuits for 555-based oscillators in books and on the internet, and the 555 in the ‘New Sound’ is easily accessible for modding.

I haven’t done much with the original Stylophones – but these should be even easier, as the resistors which fix the pitches of the notes are exposed, and it should be possible to do things to these without too much trouble.

The biggest problem with the original and ‘New Sound’ Stylophones is likely to be the cost. Since these are sought after by collectors, they can fetch rather higher prices than you might want to pay for something which you intend to experiment on!

Many stars – other than Rolf Harris himself – have been publicly associated with the Stylophone. You can read about these on the Stylophone page in the Wikipedia at http://en.wikipedia.org/wiki/Stylophone, and see pictures of them on Stylophonica, ‘the official home of the Stylophone’ at www.stylophonica.com. You can also learn more of the history of the Stylophone at www.stylophone.ws (or www.stylophone.fsnet.co.uk), the Stylophone Collectors Information Site; buy a vintage Stylophone at www.stylophone.com, the Stylophone Sales Center; or even make your own Stylophone at www.instructables.com/id/A-Stylophone!

You will also find out about the mighty Stylophone 350S, much larger than the ordinary Stylophone, with two styluses (styli?), more notes, more tones and a cunning light-sensitive filter/vibrato control. This also went out of production in the 1970s and has not so far been revived.

Stylophone 350s

These machines – wonderful thought they are, as you can see – can be seriously expensive, and you would probably want to think twice about having a go at the electronics in it without knowing what you were doing. Having said that, like the conventional Stylophones of the period, the electronics will be relatively straightforward compared to modern devices. A bit like cars, really – in the old days it was much easier for the amateur home mechanic to sort out engine problems: nowadays, there’s very little you can do. The 350S has many different ‘voices’ and that intriguing photocell circuit . . . there’s got to be some scope there.

A new type of Stylophone that has appeared in recent years is the Stylophone Beatbox: a drum machine playable – of course! – by means of a stylus, including percussion, vocal percussion and bass sounds, and able to record and replay sequences. I have some functioning ones, which may also be good for circuit-bending, and some non-functioning ones from which the attractive circular playing surface should be useful for other projects.

stylophone_beatbox

I used the case and the keyboard PCB of one of these for a Stylophone project, but not the sound-producing electronics as there were faults with the ones I acquired which I couldn’t fix.

Dübreq’s website at www.dubreq.com suggests there are more Stylophone products in the pipeline, but none, at the time of writing have appeared. Some other websites have been advertising the imminent arrival of the ‘Stylophone Remixxer’, but I’m not aware of any genuine sighting of such an object.

29
Dec
11

The Superstylonanophone

I wasn’t intending to get into MIDI instruments at the time I started on this project, and construction of the Superstylonanophone came about by accident when I acquired an apparently non-working Korg Nanopad.

Superstylonanophone1

Essentially, what it is is a cut-down Nanopad attached to a Stylophone, so that the middle 12 keys of the stylophone operate what would, in the Nanopad, have been the 12 pads.  The touch sensitivity of the original pads seems to have all but gone, which is a big loss – but the pads didn’t work at all on the device I acquired, so the present arrangement is an improvement on that.

I have since learned that stuck pads is a common fault in Nanopads, and there is currently an instructional video on YouTube at www.youtube.com/watch?v=BuomrJNd0cM, uploaded by treilaux,*  telling you how to fix them.  If you have a Nanopad with stuck pads, you could do that instead of what I did; even if you don’t, you can see from that film how I took the Nanopad apart and detached the pad section from the electronics section.

*[Edit: this video disappeared for a while, but it’s back now.  While it was away, this note said try this one uploaded by TechinWorship, which details the same procedure, at: https://www.youtube.com/watch?v=spfYhzyjP6g.  As the intro to the video says, ‘Often times the trackpad will be responsive but the pads will not. This is due to normal wear and tear over time that causes the sensors to become jammed within the hardware. If this happens to just one of your pads, all will become unresponsive. Opening up your Nanopad and separating the sensors often returns your MIDI controller to like-new condition.’]

I continued by sawing off the large right-hand section of the Nanopad with the pads in it, and was left with just the circuit board, ‘Scene’, ‘Hold’, ‘Flam’ and ‘Roll’ buttons and the track pad.  I trimmed down the back as well, to fit the remaining piece of Nanopad front panel.

Nanopad 1

Everything was removed from inside the Stylophone (it was no longer working), except the PCB with the keyboard on it.

The difficult bit was connecting the Nanopad PCB to the Stylophone PCB.  This was not difficult in principle, but only in practice.  The Nanopad pads were operated by a plastic film connected to the PCB via a 14 way ZIF socket.  The connections on the PCB were too small for me to get at – just 1mm apart – so I was hoping to find a replacement 14 way jumper cable that would be long enough to go from the ZIF socket, out of the new Nanopad enclosure into the body of the Stylophone.

I couldn’t find one: it wasn’t a proper ribbon cable, but another thin plastic thing, and in the end I had to get a short one and solder a proper ribbon cable to another ZIF socket at the other end of it.  I managed to find a type with alternate pins pointing in opposite directions, giving me 2mm space between each one.

The other end of the ribbon cable attached to the backs of the 12 middle keys on the Stylophone PCB.  I chose C – B because these are the defaults for the Nanopad’s Scenes 2 – 4, which resemble a conventional keyboard.  You can change this with the Korg Kontrol Editor program, but there seemed no point.

The 14 lines from the Nanopad PCB to its pads were one connection for each pad, plus 2 control lines, one for the top row of pads and one for the bottom row.  I was gambling that these two control lines were, in fact the same, as the Stylophone’s stylus has only one wire going to it and I obviously wanted to be able to play all 12 notes.

Fortunately, I was right, so in the end only 13 connections were needed.  However, since the Nanopad is polyphonic, it seemed a bit of a waste not to take advantage of this, so I added a socket on the side for a second stylus.  This is connected to the same spot on the circuit board as the integral stylus.  After using the Stylonanophone for a short while, I realised that this is a great asset, especially for playing drums and percussion, even if only one note at a time is sounded.

Because foot controls would be more natural for some applications (e.g. bass drum and hi-hat, or bass pedals) I added an external socket for other input devices to connect to, giving access to all 12 notes.  I’ll be writing in more detail elsewhere about the switching systems I’ve devised, and later on in the blog about any of the input devices I’ve been working on, as and when they get finished.

Superstylonanophonerear

The Nanopad doesn’t have MIDI in and out connections: instead, it has a built-in MIDI interface, and requires only a USB cable.  To allow for the possibility of future expansion (for example, I also have a Nanokeys I plan to work on), I decided to add a USB hub.  I found a flat square one that fitted into the base, and didn’t interfere with the vast amount of wiring inside the Stylophone body.  I superglued this in place.  The Superstylonanophone connects to this hub with a very short mini-USB to USB A cable, and the hub connects to the computer with a longer one.  The hub has proved very useful when I’ve needed to plug in more USB devices.

The Superstylonanophone logo, by the way, is just printed on a slip of paper tucked into the edging of the Nanopad trackpad.  This is easily removable, but isn’t thick enough to prevent the trackpad operating properly.  This was something I also saw on YouTube, at www.youtube.com/watch?v=xNKFJZX4Na4, uploaded by meltdownband.*

*[Edit: oh, dear – this video isn’t available either.  The procedure for adding the logo is very simple, though: just draw or print it on a piece of paper slightly larger than the visible trackpad and push the edges under the white plastic trackpad edging.  An ordinary thickness paper, like a printer or copier paper shouldn’t prevent the trackpad being used in the normal way.]

Sounds

There are no sound files to go with this instrument, as it’s a MIDI controller, and can be used with any real or virtual MIDI instrument.

See this post for details of the foot controller I made to go with the Superstylonanophone.

29
Dec
11

The Big Boy – Mod 4

[Edit: the BigBoy, alas, is no more!  I irreparably damaged the  circuit . . . but now it lives on in the BigBoy Beatbox, which is described here].

Big Boy verticalsm

The creation of the Big Boy came about as the result of the blindingly simple, though ultimately pointless idea of transplanting the workings of a Stylophone into the body of a Stylophone Beatbox.

I had a number of broken donor Beatboxes, and proceeded to dismantle one of these.  There are 12 ‘keys’ on the circular board, laid out in a similar way to piano keys, or the keys of a Stylophone, so one octave was available.  I decided there should be three octaves, so had two challenges: one, to connect the Beatbox keyboard to the Stylophone keyboard; two, to add switches to change octaves.

Connecting the two boards together proved fairly simple.  FirstIy I had to saw off the end of the Stylophone board to make it fit into the Beatbox case, and although this made it impossible to use the higher notes, there were still at least 12 left.  So I used the lowest 12 keys, soldering one end of a wire to the middle of each key on the Stylophone board, and the other end of the wire to the connection on the edge of the Beatbox board for the appropriate key.  It was easy to see which key on the Beatbox board led to which connection on the edge.

There are also two built-in switches on the main Beatbox board, operated by depressing either side of a plastic ring around the keys.  I also made connections to these, for later use.

The existing on/off switch was used, with its associated LED, and the space taken by the 3 way slide switch used for selecting the drum, bass or vocal beatbox modes was used for the Stylophone 3 way tone switch.  The Beatbox stylus was attached to the place on the Stylophone output board where the Stylophone stylus had been attached.

I carefully removed the Stylophone tuning pot and used it to replace the Beatbox tuning pot on the small board which is attached to the inside of the base of the Beatbox.  One end terminal of the pot was attached by a wire to the place it was originally attached to on the Stylophone board; the centre terminal was connected to +V at the same place on the Stylophone output board as the stylus, via a series of preset potentiometers, as described below.

The preset potentiometers were designed to produce the three octaves.  If there had been room for a 3 way rotary switch in the body of the Beatbox, this would have been simple.  But there wasn’t.  There was room for a three way miniature toggle switch of the ON-OFF-ON type, so I decided to use one of these.

With a simple 3 way switch, it would just have required three presets, each adjusted to produce the same note in different octaves; but with the 3 way toggle it required the middle terminal to be permanently connected, and the other two pins – representing the switch in the ‘up’ or ‘down’ position – to be in parallel with the middle terminal resistor.  This proved quite complicated, and many adjustments were required before the 3 octaves became available.  The Stylophone functions in such a way that the lower the resistance, the higher the pitch.  As the rule about two resistors in parallel means that their combined resistance is always lower then the resistance of the lowest of the two, the middle position had to be the lowest octave, and the ‘up’ and ‘down’ positions had to be two octaves higher and one octave higher, respectively.

The integral switches on the board, operated by the plastic ring, duplicated the function of the toggle switch, allowing for momentary octave changes when either the left or right switch was depressed – this only really worked when the toggle switch was in the middle, ‘off’, position, but that was the most practical setting for most uses, I found.

An extra 10k resistor had to be placed in series with the stylus connection, to ensure that the correct pitch could be achieved with the tuning pot roughly in the centre of its travel.

Big Boy horizontal rearsm

29
Dec
11

The Gemini – 3rd Mod

I was apprehensive about my third project, my final Stylophone mod for the time being, since it involved major surgery to two individual Stylophones, and I wasn’t really sure at the outset whether it would work.  In the end, in an unpredictable way of its own, it did!

The concept was simple, to generate two notes at the same time, using two Stylophone circuit boards operated by one stylus.  The ability to tune the fundamental note had to be retained, as well as means of selecting any harmony note – and, of course, it had to be possible to play the Stylophone as originally intended.

This photograph shows the main pitch control of the Gemini, the dual concentric potentiometer at the back left, as well as the fine tune, volume and blend controls on the back.  It also shows its decoration with signs of the zodiac stickers – I think the sign of Cancer (not visible) is the wrong way round, but this is not my fault, it was like that when I bought them.

Gemini high angle standard knobs sm

The first extra control to be added would be a 3 way rotary switch, to select ‘Normal’, ‘Harmony’ and ‘Modulated’ outputs.  This is just visible on the right hand side of the picture above.  ‘Normal’ would switch only one of the boards in circuit, with a mono output available to the internal speaker or to the headphone output; ‘Harmony’ would switch both boards in circuit, with one board available to the internal speaker, but both boards available to left and right sides respectively of the headphone output; in ‘Modulated’ mode, the outputs of the two boards were connected by diodes to allow the tones to interact with one another.

A dual 10k lin pot was used as a ‘Blend’ control, ranging from Board One (Oscillator 1) only to the left, and Board Two (Oscillator 2) only to the right, with varying mixes in between of the two tones produced.  A dual 10k log pot controlled the overall volume.  These were located in the circuit in place of the existing volume controls and both original volume pots and associated circuit boards were removed.

Pitch was to be controlled by a dual 500k concentric pot, the inner control for correct tuning of the fundamental pitch, the outer control for the harmony note, the interval being set by ear.  As this pot would cover a wide range, and the fundamental note would be difficult to set precisely, I decided to add a 10k lin pot, normally in centre position, in series with the inner pot, as a ‘Fine Tune’ control.

The first problem was to test if removing one stylus and connecting the ‘keys’ on one board to the corresponding keys on the other board would successfully enable one stylus on one keyboard to create two distinct notes at the same time.  Connecting the keys was easy enough, as each one has a small point – presumably included for testing purposes at the factory – to which wires could be connected.  To my relief, this procedure worked, two notes were produced simultaneously, and the interval set remained steady along the length of the keyboard.

The Stylophone’s original 3-way tone switch, as I had discovered on my first modification project, is a two-pole type, with only one pole used; so it was easy to connect the three wires from the two boards to other side of the same switch, to ensure the same tone was used on both boards.

I hoped the same would be possible with the vibrato, and connected the main boards together at the 3 inputs to the small board containing the power and vibrato switches.  This worked, too, and enabled one power on/off and one vibrato on/off switch to be used for both main boards.

It was the ‘mp3’ input/headphone output that caused difficulty, and I didn’t fully resolve this problem, I just got round it in a not entirely satisfactory way.  I had hoped that the outputs of the two amplifier boards would simply appear separate and equal at the headphone socket, and that a stereo input would appear as a stereo output.  (A stereo input is normally reproduced in mono through the internal speaker and the headphone output, as an unmodified Stylophone has only one mono amplifier in it).

I disconnected one of the mp3 inputs and one of the headphone outputs from Board One and replaced them with an input and an output from Board Two, in order to make this happen, but it was clear that one of the channels was leaking into the other one somewhere and the output was still mono, even though using two amplifier boards.  I had removed the 3.5mm sockets from Board Two, in order to fit this in the original case on top of Board One – maybe this had some effect on the stereo image, I don’t know.  But I eventually created a slightly stereo output by putting a 1k preset into the output of one channel, so Oscillator 1 was slightly to the left in the headphones, and Oscillator 2 slightly to the right.  This was the effect I was after in the first place, it just wasn’t the way I anticipated achieving it.

However, this was close enough to what I set out to create, so I considered the job done.

The following diagrams might help illustrate what I did and how I did it:

Gemini  Board 1b smGemini Board 2 sm

As it turned out, the pitches of the two oscillators couldn’t be set independently – raising the pitch of one would automatically lower the pitch of the other, and vice versa!  Not only that, but as the 500k pots were logarithmic the pitches would vary at different rates.  This apparent disadvantage, I decided, would be turned to an advantage – and would, in fact, be the whole point of ‘The Gemini’: the careful adjustment of the three pots to obtain a suitable pair of notes would become its principal performance feature.

The stylus, of course, was still fully functional, so as soon as a suitable interval was stumbled upon, this was playable up and down the keyboard.

Fitting everything back into the case was not easy, and involved quite a bit of rewiring to reduce the tangle of leads inside.  I had hoped to be able to fit everything in the original Stylophone case, but it soon became apparent that this wouldn’t be possible, so I aimed to deepen the case, as I had with ‘The Hedgehog’ – although not so drastically, as there would be fewer extra controls to add.  In the end doubling the depth proved adequate to contain the extra boards and wiring without unduly squashing them.  The extra piece of bodywork added to the case proved an ideal base for the zodiac motif stickers I added.

In use, the basic pitch seemed somewhat lower than originally intended, but it turns out that ‘The Gemini’ is perfect for bass sounds, and some excellent tones are obtained, especially in ‘Modulation’ mode.

29
Dec
11

The Hedgehog – my 2nd modification

My second modification, and first variation on a classic theme, was initially described by its inventor, Forrest Mimms III, as a ‘Sound Synthesizer’, and later as a ‘Stepped Tone Generator’ before it acquired lasting fame as the ‘Atari Punk Console’, or APC for short.

The APC consists of a pair of oscillators, using the ubiquitous 555 timer i.c.: one ‘astable’, or continuous, the other ‘monostable’, triggered by the first.  The 556 is often used, as it contains two 555s in one chip.

The design is so famous, it even has its own page in the Wikipedia.

I remembered that one of the Stylophones in my collection, the 1970s ‘New Sound’, was based on a 555, so decided this could be adapted as the first oscillator in the circuit.

This is what the ‘New Sound’ Stylophone looks like:

Stylophone Parts sm

And this is the circuit diagram from the booklet that came with it:

New Sound Stylophone Circuit Diagram sm

Looking around at various implementations of the circuit, I decided an LFO would be a handy addition, so decided to add a 556, to give 3 oscillators altogether.

I designed the circuit in my usual way by drawing, photocopying, erasing, cutting, and sticking, and ending up in this case with a very large piece of paper that had to be laid out on the floor to be read.  This is a photograph of the finished design:

270111 002 med

The middle part of the diagram is part of the Stylophone circuit.  The other parts were mainly inspired by Forrest Mimms’ own description of the stepped tone generator at www.jameco.com/Jameco/PressRoom/punk.html?CID=punk, the ‘Blast Fed Disaster’ from www.thesquarewaveparade.com, and the article at www.getlofi.com/?page_id=1395, including the Datura Mod.

As far as I recall, the 680Ω resistor shown in the circuit diagram as R8, where the circuit was broken for SW1B, wasn’t actually there and was replaced by a wire link in my Stylophone.

In the end, there were very few components to add to the Stylophone, just lots and lots of pots and switches, and yards of connecting cable.  The 556 and one or two other components for decoupling were on a small piece of veroboard, and took up very little room, but the biggest problem I had was to find enough space inside to fit the extra circuit board and all the wires in, and enough space on the outside to attach all the switches and knobs.

It was clear from the start that the Stylophone case was far too small to contemplate this.  I didn’t want to add a break-out box, or disfigure the Stylophone too much by sticking extra boxes to the side of it, so I decided to extend the depth of the case to create more room.  I bought some small pieces of 2mm acrylic, to match the thickness of the original case material, sprayed it black, drilled holes and stuck it in place.

It was now more than twice the height of the original Stylophone.  Still not deep enough.  A couple more centimetres all round of brown acrylic vaguely the same colour as the original ‘natural wood’ finish on top, and it was as deep as it was wide, with switches and knobs poking out on all sides.  This is how it acquired its nickname, ‘The Hedgehog’.

This low-angle shot of the considerably enlarged case of the ‘New Sound’ Stylophone shows most of the controls added to it to create ‘The Hedgehog’.

Hedgehog low angle 1 sm

The three on/off switches and potentiometers on the left, controlling Oscillator 1, are duplicated on the right-hand side for Oscillator 2, as are the two small touch points above.

Hedgehog inside 1 sm

It took some days to connect all the wires, and jam everything into position, but when I finished, much to my surprise, most of the functions worked straight away!  First of all, with the 3-pole SW1 (‘Keyboard off’; upper switch, front left) and the double pole SW2 (‘Oscillator on’; lower switch, front left) switches both in the ‘up’ position, the Stylophone was able to function normally; with the ‘Oscillator on’ switch down, notes played with the stylus could interact with the second oscillator; with both switches down, the stylus is not used, and the instrument is ready for full ‘Punk Console’ mode.

Classic ‘stepped tone generator’ effects can be produced with the middle switches on each side down, putting VR1 and VR3 in circuit.

Using the other switches on the sides, VR4 and VR5 alter the pitch or timbre of Oscillator 1 (the Stylophone oscillator); VR2 and VR6 can be used to alter the pitch or timbre of Oscillator 2, and thus radically affect the overall nature of the output.  The pitch range of both oscillators can also be altered by selecting one of 6 capacitors for each.

The third oscillator is configured as an LFO, connected to the control voltage input of oscillator 2, and thus affecting its pitch.  There are two sets of 6 capacitors associated with the LFO, and a variable potentiometer, which control its speed and depth (visible in the first picture above).  These controls actually enable it to move up into a similar pitch range to oscillator 2, creating some frequency modulation-type effects.  The Stylophone’s original vibrato is still available to oscillator 1.

The LFO is particularly effective when used in conjunction with the two controls on the back of the instrument: ‘starve’ (right of the picture below) – reducing the supply voltage available to the oscillators – and a flashing LED, which produces a slow, steady fluctuation in pitch (centre of picture).  Both of the pots have integral on/off switches.  A steady LED indicates when the starve control is on, and dims as the voltage decreases.  The knob on the left of the picture controls the brightness of the flashing LED, and thus the amount of effect it has.

Hedgehog high angle back sm

Also visible in the picture is a 2.5mm power socket, installed many years ago before rechargeable batteries became common, and before this series of modifications was planned.

The three feedback controls on the front are ‘on-off-momentary’ switches, which are sprung to return to centre (off).  This makes it a little easier to apply a short burst of the effect by raising the switch and letting go, rather than flicking it down, then up again.

The Stylophone is intended to be tuned in the following way:

Tuning sm

The tuning control has been extended with a length of plastic tubing so it still protrudes through the casing underneath and can be used as originally intended.  This can be seen in the picture of the inside of ‘The Hedgehog’.

The original base of the Stylophone was replaced.  It was not glued in position as it has to be opened in order to replace the battery, a 9v PP3 type.  The battery leads were extended in length to reduce strain, due to the longer distance between the circuit board and the battery compartment.

Playing ‘The Hedgehog’ is always a delight.  Because of the wide variety of interactions between the oscillators, the amount of adjustment that can be made, and the lack of any labels to remind you what each of the controls does, successive sessions are rarely identical.

Playing the Stylophone

Here are links to the sound files for ‘The Hedgehog’.

The first one is an extract from a track on my forthcoming album, slightly remixed to feature The Hedgehog’s contribution:

For hard-core electronic noise fans, the others are a slightly edited 15-minute improvisation – one long piece, but divided into 5 sections to make the files shorter, and because the different parts have a different feel to them:

A:
B:
C:
D:
E:

The Hedgehog is a mono instrument, so I’ve added a stereo spread plug-in to the recordings (made in Logic) and some reverb.

29
Dec
11

The Alien – my first modification project

My first Modification project involved a Stylophone – the 2007 re-issue – which I modified as shown below:

Stylophone labelled

1.  Power on/off.  This is the original power switch, unchanged.

2.  Drone switch.  The original vibrato switch with different wiring connected to it.  This switch causes the Stylophone to sound without using the stylus – useful in conjunction with some of the other modifications for which you need free hands.

For anyone interested in the details, I didn’t manage to document the whole procedure, but I’ve got a couple of pictures of the inside.  This one shows the end of the main circuit board and the small board for the power on/off and vibrato switches.

pic1

The original wires to the vibrato switch were disconnected, but not the other wire to the small circuit board, which goes to the Power switch.  As it’s a three-way cable, it might be easier to disconnect all of them, bend the two vibrato wires out of the way, and then reconnect the other one.

The pole of this switch (the middle of the three tracks) was attached to the highest note on the keyboard.  Each note has a small round spot where a wire can be connected, and you can see the spot for this note nearby on the keyboard circuit board.  The ‘on’ end of this switch is attached to the point where the stylus wire is connected to the third circuit board inside.

(In the picture, where it says ‘connect the end one to the end of the stylus wire’, it means the end track on the circuit board, not the end of the wire itself, which is going to be used for something else later.  Note that both these switches are SPDT, but used as SPST, with one end not connected).

3.  Tone.  This is the original 3-way tone switch, unchanged.  It’s a double-pole switch, with only one side used, so there ought to be plenty of scope for adding functionality to it.  I tried adding momentary switches linking the three wires that go back to the circuit board, for brief tone bursts, but in the end didn’t leave them in as it was hard to find one that worked in each of the three tone settings.  Adding potentiometers didn’t seem to have any effect.

4.  Feedback loop.  This switch and potentiometer are wired to two places in the output circuit of the Stylophone.

The switch turns Feedback on, producing a continuous high-pitched sound, adjustable by means of a 220k Log potentiometer.  When using the stylus with this circuit on, very interesting tones are produced as the feedback tone modulates the note played with the stylus.  In Drone mode, a ‘double’ tone is produced, very rich in harmonics.

Once the feedback wires are attached to the circuit, even with the switch off, a hint of the high-pitch breaks through to the output, and there’s a hint of the modulation when notes are played with the stylus.  Apart from this one effect, ‘The Alien’, as it is known, can be used with all the switches off as a normal Stylophone, with variable rather than fixed vibrato.  Feedback is such an effective tonal modification, though, I didn’t want to leave it out.

5.  Wide-range pitch control.  This is a 2.2M Log potentiometer which allows the pitch to be changed from a very high note, to a very low note – so low, that it hardly seems a pitch at all, almost a beat.  Can be useful!

6.  Pitch Effects on/off.  This switches the Stylophone’s pitch control out of the circuit as well as switching on the modified pitch effects.

7.  Wide-range pitch control on/off switch.

These 3 controls were the most difficult to arrange, especially as I wanted the Stylophone’s original pitch control to be used as normal when it wasn’t switched out of the circuit by 6.  This meant breaking the original connections to the pitch potientiometer and putting in some new ones.

pic3

The other difficulty was that the Stylophone doesn’t mind going right down to a very low pitch, but doesn’t like going up too high.  If you try to make it go too high, it will cease sounding and you can only get it to work again by switching off and on, or in some cases switching off, removing the batteries, putting the batteries back in and switching on again.  This is a common phenomenon in circuit bending, but I didn’t install a battery cut-out switch, as is often done – there’s no need for this to happen, even with all the modifications working, so it could be designed out.

Accordingly, the wide-range pitch control doesn’t go all way from + v to 0v, but is connected to +v by a variable resistor, enabling you to set the highest note it will be able to produce and stop it from going silent.

This diagram shows how the rest of the connections to the switches are made and shows three preset variable potentiometers which are used.

Alien Switch connections2 sm

Note that I found it easier to connect the 3 presets to the TOP side of the circuit board, rather than the side in the picture, with the components on it.  The Stylophone’s pitch control does face this way, and it’s easy to find space on the tops of the two legs to solder the potentiometers.  You just have to make sure they’re out of the way when you put the back of the Stylophone on again.

Make sure when turning the circuit board over that you identify the correct two legs.

To adjust them, start by setting them to mid-position.  Switch on the part of the circuit connected to each one – e.g. the wide-range pitch control – turn it up to maximum pitch and adjust the preset upwards to the point just before it goes silent.  There’s a small area just before this where the tone starts to degrade, and you could turn the preset down a little so this is never reached in normal use.

The original pitch control is somewhere in mid-position in normal use, but don’t forget this may be working in some settings, and may have to be turned up when adjusting the presets.

Once this has been done once, it won’t need doing again.

9.  LDR (Light-dependent resistor, photoresistor or photocell) and LDR on/off switch.  The LDR is a NORPS-12, which has wide resistance range.  The less light that falls on it, the lower the pitch.  It depends very much on the ambient light how close you need to put your hand to it to achieve useful effects, but in many circumstances I’ve found very close – even to the point of touching it.  This is not a bad thing, as you don’t have to stand away from it to stop it working, and it almost resembles a touch switch in this way.

A handy accessory to have is a small torch, with which you can raise the ambient light level and increase the pitch by shining it on the LDR.  I have an LED-based cycle light – 99p from a supplier in Hong Kong – which is very bright, and also has a number of flashing modes, which produce LFO-type effects.

8.  Variable vibrato.  Connect a 1M Log potentiometer between the two wires you disconnected from the power/vibrato board. This gives a transition between full vibrato and no vibrato at all.  Only two of the connections on the potentiometer are used, and you might want to experiment with which of the end ones you use as the degree of control is different, and I can’t remember which way round I put them.

The Stylophone’s volume control (next to the LDR switch on the right hand side, not pictured) was left in place, and still functions as before.  It has no effect, however, when Feedback is on.  You must do as we did with the original Stylophone, which had no volume control, and put your hand over the speaker!  And watch out when using earphones!

General construction notes

1.  The first thing is that the top and bottom halves of these reissue Stylophones don’t come apart easily, like the old ones did.

The old ones were powered by a 9v battery which was on the inside, so you had to take them apart easily to replace the battery.  The reissue ones take 3 AA batteries in a battery compartment which is accessed from the outside with a cross-point screwdriver, so the top and bottom are superglued together.

The 4 main points where they’re glued are near the corners on the long sides, and there is no alternative but to insert a knife or screwdriver in the gap and prise it open.

2.  The black blob hides the main processor that does all the sound generation.  It seems a little sensitive, so avoid soldering near it for all but the briefest time, and don’t solder with batteries in.  I managed to ruin a couple, almost certainly by doing one of these two things.  In particular, be careful when connecting the drone switch to the keyboard circuit board.

3.  I also painted the base black and superglued a metal alien face to the front.  Neither of these things has in any way improved the sound, except insofar as the effect it has on the mind of the player.

The alien face, by the way, actually comes from Roswell, New Mexico in the USA, site of the original UFO flap in 1947.  How much more authentic can you get!

Acknowledgements

Some useful pointers came from a well illustrated article by TraceKaiser on the www.stylophonica.com forum; and from circuit-bender Freeform Delusion, www.facebook.com/pages/freeform-delusion/144587583120.

29
Dec
11

How I started

I’m writing this Blog to document some work I’ve been doing in the field of electronic music-making.

I wasn’t an expert in any of these things before I started – and I’m probably not an expert in any of them now, but I’ve learned a lot as I’ve gone on, and I hope if I can pass it on it’ll be a source of interest and in some small way an inspiration to others who are getting involved in this field

When I began thinking about this project I decided to do it in the following way:

a).  To avoid working with computers (until the very end).

I’d used computers extensively in my music before, from Logic for straightforward composed pieces to a variety of other programs for electronic composition or sound treatment.  I expected to return to using the computer in the end, but with the benefit – hopefully – of new knowledge and new sound devices.

b).  To incorporate where relevant some projects I’d started, and mostly not finished, many years ago.

I’d made some guitar effects with a degree of success that could be described as ‘mixed’ – some of them I use to this day, which work very well and can’t or don’t need to be replaced by anything new; some are still around, not quite working the way they were intended to; some never worked at all!

So I decided not to go back to guitar effects, but to concentrate on sound producing devices.

c).  To explore certain specific ‘movements’ in electronic sound-producing, such as ‘circuit bending’ and ‘Lunetta’ devices, and construct some of the ‘classic’ designs along the way.

d).  To explore alternative methods of music input – isomorphic keyboards, game controllers, and other home made devices.

One of the intentions behind this was to create music in more of an informal and  ‘live’ way than I had done using the computer; another was to explore the variety of music- and noise-producing devices now available – usually cheaply in sales, second-hand shops and on eBay.

I also wanted to pursue my obsession with the Stylophone, an early electronic synthesiser of the late 60’s and early 70’s, but recently reintroduced.

I’ve divided the different parts of the project into the following categories:

1.  Modification

In this first phase I would take existing devices and add new features, or expand existing ones.

My principle in doing this was understanding the circuits (to a certain degree) and making appropriate changes to produce specific effects.

2.  Construction

Phase 2 was to build a number of sound-producing devices from scratch, using circuit diagrams and descriptions from books and magazines (I had a number of these collected over the years, and hand-drawn circuits copied from publications in libraries) and from the internet.

Again, a certain amount of understanding of the principles of the circuits would be necessary.

3.  Circuit Bending

In this phase the idea was to take existing electronic instruments – children’s toys mostly – and make them produce sounds they were never intended to produce, mostly without worrying too much about the circuits that produced these sounds and how they were working, which I felt was more within the spirit of the enterprise.

4.  Freeform designs

The intention then was to extend the knowledge gained in previous phases to create new designs, partly modified, partly constructed, incorporating past ideas I had had, but never put into practice and new ideas discovered through experimentation.

5.  Software/MIDI

This phase was to be mainly computer-based, involving programming, which I had not done before.

As it turned out, I was overtaken by events, and parallel with the Modification and Construction, have got involved in some slightly different areas.  However, I’ll write about each of my projects in order, and put them in the appropriate category.




andymurkin

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