Archive for the 'Modification' Category

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.

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15
Jan
18

The Blue Cow

Having just finished a couple of projects designed for automatic control via the Bigfoot sequencer, I was looking for a similar toy that could be played manually.

The Blue Cow seemed to be exactly the kind of thing I was looking for. which could be worked on with a combination of modification and circuit-bending.

There are buttons which make the sounds of a cow, cowbell, cat, dog and pig; two switches – the ducks’ beaks – which play a short musical sequence and light up the 6 LEDs; and three mechanical controls.  One, a snail which moves slowly across the cow’s back, makes no electronic sound, but there are two others which do: a rotating ball which makes the cowbell sound as it turns, and a rotating control with finger-holes, which moves the cow’s tail and plays a tune with a bell-like tone.

*

I opened the back of the device and took a close look at the PCB inside.

The first thing I noticed was an extra switch which hadn’t been used.  It had the word ‘sheep’ next to it, so I eagerly connected a pair of wires to it and, sure enough, a baa emerged.  So the first thing I did was add an extra switch on the front of the cow to produce this new sound.

*

After that I searched for the resistor which would affect the pitch of the sounds.  It took a while, but I found it, removed it from the board, and attached two wires in its place, running to a potentiometer so that the pitch could be varied.

In this view of the circuit board 1 indicates the previously unused switch, and 2 indicates the position of the pitch/timing resistor.  The wires now connected to these two sections are on the underside of the board.

It took a little experimentation to find the correct value for the potentiometer, to ensure sufficient pitch variation, but not to increase or decrease the resistance so much that the device crashed.  This is the normal thing when replacing a timing resistor.  In this case, a 250k potentiometer was the best value, with a 100k trimmer to adjust the minimum resistance.

The potentiometer went on the front of the cow.

*

I unscrewed  the sections behind the 4 main sound buttons, and checked the additional circuit boards which were connected to the main board by a series of red wires.  There were 14 of these these wires, which went directly to the sound-producing chip.

Some of these wires went to LEDs beneath the buttons, so  I tested the others by connecting them in pairs, and found various combinations which would produce almost all available the sounds, including the newly-discovered sheep.  If I included one of the connections of the switches under the ducks’ beaks, all the sounds were available, and I began thinking of extra ways to access them.

First of all I added four tilt switches, so different sounds would be produced as the device was moved around.  These were a simple and cheap type – about 10p each – but very effective.  Constructed in a small can with two legs, not unlike an electrolytic capacitor in appearance, an internal connection is made when the can is tipped from horizontal to vertical.

I glued the switches inside, left, right, top and bottom, with a different sound connected to each.  The arrows in the following picture indicate two of the switches in situ.

*

One awkward thing about the circuit – especially with the tilt switches in place – was that there was no on/off switch: the power was on – and the device ready to make noises – as soon as batteries were inserted.

So, I decided to add one.  I found a nice one, described as an SPST illuminated rocker:

The odd thing about it, as an SPST, is that it has 3 contacts.  It took me some time to work out, but its normal function is to switch +v from one outside contact to the centre; the other outside contact – not connected to the switch – is for a 0v connection to the internal LED.  In this case, the power lead from the batteries connects to the ‘off’ side of the switch, the lead to the circuit board connects to the centre, and the 0v lead connects to the ‘on’ side of the switch.  In this way, when the switch is turned to the ‘on’ position, power is connected to the circuit board and the switch lights up – very attractive!

I liked these switches so much, I bought several of them at about 30p each.  They were labelled as suitable for 12v – their origin is for use in the automotive industry – but lit up fine from the Blue Cow’s 4.5v.

There’s quite  variety of illuminated switches available, all of which would beautify a project where a +V switch was required.  There were also square ones:

although I always find these more difficult to mount than round ones.  The one on the right looks interesting, as it’s a centre off with a latching switch one way and a momentary switch the other.

One UK outlet has a whole variety of these, including toggle switches, push switches and pull switches:

At this time I also added a small SPDT switch to change the output from the small internal speaker to 4mm external speaker sockets or to an audio out socket.

In the  following picture 1 = the internal/external speaker select switch; 2 = the speaker select switch inside; 3 = the external speaker sockets; 4 = the audio out socket.

*

Here’s a short demo of the Blue Cow.  In this case it was connected to an external speaker and the sound recorded via microphones.

12
Oct
17

The Carousel Keyboard

‘Carousel’ was just the brand name of this toy keyboard, it didn’t unfortunately look like a carousel . . .

. . . but having just finished the Animal Band and The Telephone, I wanted, while it was in my mind, to work on another device that could be controlled by the Bigfoot, only this time with a full two octave span, the ability to play a variety of different scales, and be tuned to play these scales in any key.

I opened up the Carousel, and it looked as though it would fit the bill.  The chip on which it was based was securely hidden under a black blob, but there were sufficient additional components to make me think a few simple hacks would be possible.

First of all, I wanted to check the instrument’s ability to be tuned.  I inserted batteries, switched on and began testing the circuit using the traditional wetted finger method – that is, starting the instrument playing one of its demo tunes and applying a wetted fingertip to different resistors on the board.

After a short test, I found the resistor that controlled the instrument’s pitch and timing.  It was a tiny SMD (surface-mounted) component, just 3 or 4 millimetres long, so was easily – though carefully – removed.  Its value – again, printed on the circuit board – was 300k, so after it was removed I replaced it with a 1M potentiometer, to increase the range of notes the instrument could produce.  The spot from which the resistor was taken is arrowed on this photograph, and the two leads going to the potentiometer can be seen:

(Also visible in the background are the wires connected to the PCB tracks required to trigger the notes).

I experimented with the resistance and found that the minimum the device would accept without crashing was about 200k, so I added an extra couple of 100k resistors before the 1M potentiometer, and found that a considerable variation in the pitch was achievable.

*

Early on in this process I disconnected the internal speaker, which was quite terrible, and added my standard 4mm banana sockets for attaching an external speaker.  The sound was 100% improved, and experimenting became a great deal more pleasurable.

Just beneath the speaker sockets a switch can be seen, which I connected up to allow the internal speaker to be selected, if an external speaker wasn’t available.

I later added an audio out socket, to allow the Carousel Keyboard to be played through the Taurus amplifier.  At first this didn’t work at all – virtually no sound came out, even though it would work with the internal or external speakers.  But I realised the output of the circuit needed a load in place of the speaker, so I put a 10 ohm resistor between the audio out and ground pins on the audio out socket, and after that it worked fine with an external amplifier.

*

I was saved from having to do the job I had performed on the Animal Band and The Telephone, working out which PCB tracks needed to be connected to produce the different notes: to my surprise, this was printed on the back of the circuit board.

There appeared to be an 8 x 5 matrix, so connections were made to the relevant PCB tracks, ready to be brought out to a new board.

*

The intention was to be able to control the keyboard with the Bigfoot sequencer, so I added a 5-pin DIN socket and 4050 buffer, as usual, ready to accept the Bigfoot’s 4-bit binary input.  This is in the form A B C D, where A is the last – rightmost – bit in the binary number, and D is the leftmost.  A is sometimes referred to as the LSB (Least Significant Bit) and D the MSB (Most Significant Bit).

The binary number 0010, for example (the number 2) would mean that D was 0, C was 0, B was 1 and A was 0; in practical terms this means that input D was 0v, C was 0v, B was +v and A was 0v.

I needed one of the inputs (D) to be inverted – i.e. if the input was 0v, I needed +v, and if the input was +v, I needed 0v – so with the 4050 was a 40106 inverter, with sections which change 0v to +v and +v to 0v.  There was very little space inside the keyboard case, so the board with the 4050 and 40106 was tucked under the output socket.  (This was before I added the 10 ohm resistor on the socket).

The circuit of the input section was like this:

There are 6 buffers in the 4050 chip; 4 of these are used (marked A B C D) and the inputs of the other two are connected to ground.  Likewise, there are 6 inverters in the 40106; 1 of these is used and the inputs of the other 5 are connected to ground.  Unused inputs on CMOS chips should normally be grounded like this to ensure correct operation.

Normally, I would use a 4067 to cover the two octaves produced by the Bigfoot – as in the Animal Band and The Telephone – but in this case that wouldn’t work.  The 4067 is essentially a 16-way switch with a single pole; in this case there were 4 different ‘poles’ to which connections needed to be made, since the notes are produced by a matrix.

Using four 4067’s would be perfectly possible, but unnecessarily expensive – each one costs between 30 and 50p, and is physically quite large, being in 24 pin wide format.  As there would only be 4 or 5 connections to each pole, it would be more effective in terms of cost and space in this circuit to use 4051’s.  The 4051 is an 8 pole switch which works in more or less exactly the same way as the 4067, but is physically smaller  – and costs less than 15p!

An important difference between the 4051 and the 4067 – related to the number of outputs – is that the 4067 requires a 4-bit binary input (16 numbers, from 0000 to 1111), but the 4051 only a 3-bit (8 numbers from 000 to 111).  This means that a different way must be found with the 4051’s to ensure that outputs for the first 8 numbers are separate from the outputs for the second 8 numbers.

This can be done by using the Enable/Inhibit pins of the 4051’s.  Each 4051 – just like the 4067, in fact – has an Enable/Inhibit pin: if this pin is at 0v, the chip will work, and convert its binary inputs into individual outputs; if the pin is at +v, it won’t work.

So, the first 3 inputs from the Bigfoot binary input socket, A B & C, are passed on to the 4051’s in the next part of the circuit, but the 4th input, D, is not.  Instead, the 4th digit is used to turn pairs of the 4051’s off and on via their Enable/Inhibit pins.

4051’s 1 & 2 output the lower 8 numbers (0000 to 0111), so as long as the 4th, leftmost, digit is ‘0’, these two 4051’s are enabled.  0v at the Enable/Inhibit pin achieves this.

4051’s 3 & 4 output the higher 8 numbers (1000 to 1111), so if the 4th digit is ‘1’, an inverted signal from the 40106 sends 0v to enable these two.

The circuit to convert the binary input to separate outputs looks like this. (The 40106 gate is repeated from the diagram of the input circuit):

The lower 8 notes are divided between the top two 4051’s in the diagram, which work together with no overlap in notes, and the higher 8 notes are divided similarly between the bottom two, according to which common pin they must connect to.  The pin connections are named in the diagram as they appear printed on the keyboard’s main PCB: the 4 common pins are connected to tracks named BP10, BP11, BP12 and BP13.

The reason there are many more than 16 output pins shown is connected with the principle of the Bigfoot sequencer.  The idea is that the sequencer outputs the notes of a scale – do, re, mi, fa, so, la, ti, do – but the exact scale – major, minor, melodic, harmonic, etc. – is determined by switches on the receiving instrument.  Normally there would be 5 double pole switches, but due to the configuration of the pins in the Carousel keyboard, one of the switches (SW2) needs to have 3 poles.

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As with other of my designs like this, there wasn’t a lot of circuitry as such – just a lot of interconnection between the chips.  After soldering the dozens of wires needed to link the 4051’s with the switches and the Carousel keyboard’s PCB, the inside of the instrument looked like this:

There was just enough room for the new circuit board with the four 4051’s on it.

The Chessboard Keyboard proved very useful in checking that everything was working properly – one wrong note revealed a connection error on one of the switches! – and the 4 LEDs were a good double check that the binary input was being interpreted correctly.

*

Although the pitch control potentiometer worked well, I decided there was a need to be more precise about the pitch, which would effectively set the key the instrument would be playing in when controlled by Bigfoot.  So, as I had done earlier with The Telephone  – referred to above – I added a switch to change between the potentiometer and a 12-way switch.

Between each of the output pins of the switch, I inserted a 100k trimmer – with an extra 100k trimmer before pin 1 – so that the pitch of the instrument could be set to any one of the 12 steps in the octave.

In The Telephone I used ordinary single-turn trimmers, but I though it would be a good test to see if multi-turn trimmers would be as good – that is, as accurate in establishing the pitch, remaining in pitch, and not taking up too much space in the cramped enclosure.

The type I chose looked like this:

Buying 20 at a time enabled me to get them at a reasonable price – about 8p each, although this was probably twice as much the single-turn trimmers I had used in The Telephone.  They were also much more than twice as big.

However, I soldered them all in place and set about adjusting the pitches.

In this instance, I didn’t really find a big advantage in using the multi-turn trimmers.  I was tuning the pitches by ear – maybe I was able to be more accurate than with the single-turn trimmers, maybe not.  It took longer to tune each note, of course, because of the number of extra turns required.

I would have been glad if the potentiometer/trimmer arrangement had been a bit smaller, but I found space on the right-hand side of the keyboard to fit it in with the potentiometer and the other switch.  This picture shows 1 – the 12-way switch with trimmers, 2- the 1M potentiometer, and 3 – the SPDT switch which allows either the 12-way switch or the potentiometer to be selected.

I chose two knobs which fitted the space available on the top surface, drilled holes and fixed them in place.

*

That was everything I planned to do with the Carousel keyboard for now, so I carefully closed up the case and screwed it back together.  I had to cut some rectangular holes in the base to make room for the 5 switches, but surprisingly everything else fitted in.

 

23
Sep
17

The Alien Choir

The Alien Choir wasn’t a device I particularly wanted to circuit bend- the alien voices it makes are fine as they are!  – but I wanted to do a couple of things to make is easier and better to use.

The Alien Choir is one of the ‘Finger Beats’ series.  These are recognisable by their distinctive design, and are all operated in a similar way, using light finger pressure in certain places on a colourful illustration on the front.

I don’t have an instruction book with mine, so it’s not clear that all of its functions are working – in particular, recording samples with the built-in microphone – but it makes 8 excellent alien voice sounds.  The volume of the sounds can be turned up or down with the ‘+’ and ‘-‘ buttons on the left-hand side.

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First of all, although 3v isn’t an odd or unusual value, I decided to add a socket and dc converter to allow the device to be powered by a mains adapter or larger – e.g. 9v – battery.  To this end I also added a small square of velcro to the back, as I had with other instruments before, to allow one of my 9v battery holders to be attached.

The dc converter was a small and inexpensive (less than 50p) module, which didn’t need any additional components, just an input voltage from 20v down to about 1v higher than the desired output voltage.  The output voltage is set by means of a small trimmer on the board.

In this case I found that the required voltage, as measured on my multimeter, needed to be a little lower (about half a volt lower, in fact) than the anticipated 3v in order for the circuit to work smoothly.  I don’t know if this is something specific to the Alien Choir, a difficulty in measuring the voltage precisely, or what.

Inside the device, I added a switch to choose between the battery or the external socket.  In the following picture  1 indicates the socket, 2 the dc converter and 3 the switch.

The device has a 3.5mm audio out socket (and an audio in, in fact, as can be seen in the lower right-hand corner of the picture above), but I decided to add banana sockets for connection to one of my external speakers.  This always produces a much better sound than the small built-in speakers these devices are fitted with.

The small switch on the right selects either the internal or external speaker.

I hope this will be a useful – and certainly attractive – addition to the ‘Outer Space’ section of my instrument collection.

06
Sep
17

The Animal Band & The Telephone

This project came about as I was looking through my collection of electronic toys for additional devices that could be controlled by the Bigfoot sequencer or the Chessboard keyboard.

I don’t know if ‘Animal Band’ and ‘Telephone’ are the correct names for these toys, but they are sufficiently descriptive to identify them amongst my various devices.

Both the Bigfoot and the Chessboard encode the 15 pitches (2 octaves) they can produce into 4-bit binary numbers so that they can use standard 5-pin DIN connecting leads – the same as MIDI leads – rather than more complex multi-way connectors to control sound-making instruments.

I came across two devices, which were rather limited in that they played only a one octave scale; but it was the same scale – B major – and one of them had not only small animal musicians who moved as the notes were sounded, but was also capable of playing a scale with various animal noises.  For some reason, this scale turned out to be A major, but this was only a minor inconvenience.

The additional electronics required would be similar to those in The StyloSound, the main thing being a circuit to convert the binary number input from the Bigfoot or The Chessboard to the individual notes of the scale.  Both the devices would need one of these.

The basic circuit I use looks like this:

Receive circuit 3

At the beginning, the input passes through a non-inverting buffer.  (There are 6 connections from the input to the buffer in case a later plan for operation via MIDI is implemented, which is designed to use 6 bits.  For the time being, only the first 4 are being used, the other 2 remaining unconnected).

The purpose of the buffer is to reduce the incoming signal level (which, from both the Bigfoot and the Chessboard, is at 9v) to 4.5v, the voltage of the Animal Band.  The 4050, unusually, is able to deal with an input signal which is higher than its supply voltage, which makes it ideal for this purpose.

When functioning, the 4067 will interpret the 4-bit binary input on pins 11, 12, 13 and 14 as a decimal number from 0 (0000) to 15 (1111) and act as a switch, connecting pin 1, the Common, to one of its 16 outputs on pins 2-9 and 16-23.  Each of the 4 binary inputs is held at 0v by 100k resistors, interpreted as a ‘0’ by the 4067, so a +v pulse on one or more of the inputs pulls them high, acting as a ‘1’

To avoid silences – Bigfoot produces 16 notes, the Animal Band produces only 8 – the output pins for notes 9 – 15 are connected to the pins for notes 2 – 8.

Pin 15 is brought out to an SPDT switch.  When connected to +v, the 4067 is turned off; when connected to 0v, it is turned on.  The Telephone would have a similar switch.  In this way either instrument can be set to work or not work without disconnecting the power.

*

To find exactly where to connect the Common and output pins of the 4067 I needed to search inside and test different points on the printed circuit board.

I removed the top:

Animal Band top

and examined the inside:

Animal Band inside marked

The important sections are marked.  (Normally the LEDs are pointing upwards, but I was in the process of examining them when I took this picture and had unscrewed the circuit board on which they are mounted).  In the centre of the device you can also see the rod by which the stepper motor moves the figures of the animal band when notes are sounded, and at the bottom the actuators which are pressed by the keys.

The first thing I did after opening the case was to give the actuators a clean.  They are the typical type – like computer keyboards or game controllers – which, when pressed, connect together two narrow tracks on the PCB.  If dust and dirt get inside them, they can operate erratically.

This is a typical example (from The Telephone) of the PCB tracks underneath a button:

Button pad

Apart from cleaning these small PCB tracks, I gave the carbon or graphite blocks which make the connection a light scrape to make sure their surfaces were also free of dirt and dust.

The important connections inside the Animal Band seemed to be grouped together in the bottom left-hand corner, so these are the connections I looked at first.  After testing them, I could see that the following connections needed to be made:

Animal Band PCB

The point marked ‘Common’ needed to be connected to pin 1 of the 4067, and the 8 notes to first 8 output connections on the 4067.  (Actually, output 1, pin 8, in the Bigfoot system is not connected, so the unit is silent on receipt of 0000.  The first note sounded is 0001, so the outputs used are 2-9, starting with pin 7).

In the Bigfoot system, an instrument which can sound all 12 notes  in an octave would have switches to raise or lower some notes of the scale (the 2nd, 3rd, 4th, 6th and 7th notes), but the Animal Band and the Telephone are fixed to play a major scale, so these switches aren’t needed.

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Finally, there needed to be a circuit to connect the Animal Band and The Telephone.  This would have to combine the input from Bigfoot, the Chessboard (or other 4-bit binary input) and send this in binary form to The Telephone.

This consisted only of inputs from two DIN sockets, entering via diodes, and passing through a second 4050 buffer.

The circuit board ended up looking like this, as I had originally planned to include a further circuit which would convert 16 individual inputs to a 4-bit binary output (as used in the Chessboard):

circuitboard

The large 24 pin chip at the bottom left is the 4067; the two chips above are the input and output 4050 buffers; the other 3 chips are two 4532’s and a 4071 for the unused binary-converting ‘Send’ circuit.  The diodes in the bottom right are for the inputs from Bigfoot and the Chessboard.

The board was designed to fit into the rear section of the Animal Band, behind the ‘organ pipe’ section with the LEDs in it.  I added 6 extra LEDs here, connected to the 6 outputs of the 4050 input buffer.

Most of the connections – including the 6 new LEDs – can be seen in this view of the inside, just before putting the case back together.

IMG_0947-2

This picture shows 3 of the new sockets and switches.  1 = the 5-pin DIN Out socket; 2 = the 4067 Enable/Inhibit switch; 3 = the audio out socket.  When a 3.5mm plug is inserted into the socket, the speaker connection is cut out.

IMG_0950-2

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The Telephone needed a similar circuit.  The 4067 is one of my favourite chips, and I’ve been using it for some years, but recently, it seems , the Arduino hobbyists have started to use it, as there is now a reasonably-priced breakout board available, using an SMD version of the chip.  This looked like a real time-saver for me, so I bought a stack of them – at a cost of about 70p each – and The Telephone was my first chance to use one.

4067-Breakout-BoardAs can be seen, the 16 outputs are brought out on the left-hand side of the board, and on the right-hand side are ‘SIG’, which is the Common output on pin 1; the 4 binary inputs S0-S3; ‘EN’, the Enable or Inhibit pin; +v and Ground.

I couldn’t use this breakout board in every situation: the information with it said the maximum voltage should be no more than 7v – elsewhere I have even seen 6v.  I think the intention is that it would be used with 5v, like the Arduino, but in any event the 4.5v I was planning to use with the Animal Band and Telephone would be well within the limits.

Inside, The Telephone looked like this:

Telephone inside

The main circuit board inside The Telephone sits under the 12 buttons of the keypad.  It looked as though the important connections were down the right-hand side of the board, so, tracing the tracks, it was possible work out which ones needed to be connected to produce each of the notes The Telephone was capable of.

Track 8 was the ‘Common’.  This track needed to be connected to one of 8 of the other tracks to produce the notes of the scale.  I identified which 8 tracks these were and connected these, plus the Common, to the 4067.  As with the Animal Band I connected outputs 9 – 15 to outputs 2 -8 to make sure The Telephone would be constantly sounding – except when in receipt of a 0000 input.

According to the circuit diagram of the module, it appeared that the Inhibit or Enable pin  was tied to Ground with a 10k resistor, so the unit would automatically be working when the power was switched on. 4067 breakout board schematicThis meant that only a SPST switch would be required to connect the pin to +v if it was necessary to stop it functioning.

The telephone was a less complicated unit than the Animal Band, so I just needed to connect the 4067 module to the input via a 4050 buffer, for which I just used a 16-pin i.c. socket, rather than a piece of veroboard:

Also visible in this picture are the four 100k resistors connecting the inputs of the 4050 to ground, and the audio out socket, which cuts out the internal speaker when a 3.5mm mono plug is inserted.

The outputs of the module were connected to the appropriate points on the Telephone PCB:

The only other thing to add was a switch attached to the enable/inhibit pin of the 4067 to allow the unit to be switched off without removing the power.  As mentioned above, the enable/inhibit was attached to ground internally in the module, so the switch just required a connection to +v, which would stop the 4067 from functioning.

This switch can be seen on the front left of this view of the outside of the finished unit:

On the rear can be seen the audio out (top) and 5-pin DIN (bottom) which can accept input from the Bigfoot sequencer, or a device compatible with the Bigfoot 4-bit binary note system (e.g. the Chessboard keyboard).

*

Having reassembled everything, it was time to check the devices in operation with the Bigfoot and the Chessboard, plugging them together with standard 5-pin DIN (or MIDI) cables, like this:

Everything seemed to work as expected, and the two units played in unison – or individually if one or other of the enable/inhibit switches were turned off – when operated either by the Bigfoot or the Chessboard.

Click here for a short film of the set-up taken on my iPhone.

 

26
May
16

Stylophones 5 – The Melophone

There are a number of different instruments called the ‘Melophone’ or ‘Mellophone’.  The one on the left in the picture below (by Kc8dis at the English language Wikipedia) is a brass instrument used in marching bands and the one on the right is ‘a cross between a guitar and a harmonium’, according to the Squeezytunes blog (at http://squeezyboy.blogs.com/squeezytunes/2008/02/melophone.html, from which the pictures came).

Mel(l)ophones

However, this Melophone which I recently acquired, is clearly a type of Stylophone – and a very stylish type of Stylophone at that!

Melophone2

Melophone1

I had never heard of this Melophone before, and found only a single reference to it on the internet.  A glance at the accompanying booklet – which, as you will see below, follows exactly the same style and format as the booklet from a 1960s/70s Stylophone – shows that it was not written by a native English speaker.  The company that manufactured it is (according to this website: http://www.pewc.com.tw/eng/) or was (according to this Wikipedia entry: https://en.wikipedia.org/wiki/Taiwan_Mobile) founded in Taiwan in the 1950s and acquired the name ‘Pacific Electric Wire and Cable Company’ on December 30th 1957.

The company would, therefore, have been in place to manufacture the Stylophone after its invention in 1967.  It looks as though it may have done so for some years as the picture on the box shows a Melophone with the early Stylophone keyboard with the black non-playing sections; just as the Stylophone was updated with a new keyboard, so it seems was the Melophone.

Box

The flap has a sticker on it showing the colour as yellow, which this one is; but other colours were presumably available.

It is, incidentally, not ‘Colour’, but ‘Color’, which may be an indication of the market it was intended for: Asia or America.  There would be no reason why it should not be intended for the UK, as the legend ‘Made in Taiwan’ was commonly seen during that period – except that genuine, British-made Stylophones were available over here, and Dübreq would surely not want to allow or encourage competition.

*

The similarities with the Stylophone – its appearance as well as its booklet – are striking: particularly the distinctively-shaped keyboard with its recess above to hold the stylus.

Stylus01

As can be seen  in the above photograph, the size and method of connection to the stylus are also the same as the Stylophone, and a detailed comparison of the yellow Melophone stylus with a black Stylophone stylus, shows that their dimensions are more or less identical:

Stylus02

Nevertheless, there are significant differences – aside, of course, from its handsome ‘Grand Piano’ shape!

First of all, although apparently identical, the Melophone keyboard is longer.  With a standard Stylophone on top, this can be clearly seen:

Keyboards

There are 2 extra notes at the bottom end of the keyboard, G and G#, and 1 extra note at the top, F – that is, 23 notes in total, as opposed to the Stylophone’s 20.

You can also see in the above photograph that the Melophone lacks the traditional Power and Vibrato switches at the left-hand end of the keyboard.  Instead, the Power On/Off switch is incorporated into a volume control on the top of the Melophone, to the left:

On_Off_Volume

The Vibrato switch is found on the left side, together with a control the standard Stylophone never had – an Octave-change switch!

Side

Using this switch, the range of the Melophone can be extended by another 12 notes, giving the instrument an exceptionally wide range.

Turning the instrument over reveals the battery compartment – like the original Stylophone, the Melophone requires a 9v PP3 battery – and the three screws which need to be undone to access the inside.

Back

The circuit board inside is quite different from the standard Stylophone – and so is the circuit itself: no fewer than 6 transistors can be identified in the following pictures (These are 1 x ED1402A, 3 x ED1402D, 1 x ED1402E and 1 x ED1602E, which are all NPN General Purpose transistors – except the 1602E, which is a PNP):

Inside1

Inside3

Inside4

Inside2

It has no tuning control like the standard Stylophone; I wonder if the top has been removed from one of the potentiometers in the first internal picture in order to make some pitch adjustment.

*

Comparing the Melophone Booklet with a typical Stylophone booklet of the period, the close similarity is evident:

Two CoversRead the Melophone Booklet

Even the two pieces of music at the back of the booklet are the same: ‘Silent Night’ in the key of Bb and ‘The Londonderry Air’ in the key of C, although references to ‘Stylophone’ or ‘Dübreq’ are noticeably absent.

*

One website (http://www.miniorgan.com/lib/view.php?miniorgan=80&view=E&srch=&srch_type=&sortby=&output=14) pictures and describes as ‘another very cheap STYLOPHONE clone’ an obvious copy (which they date to 1976 – the year after production of the original Stylophone ceased, according to the Stylophone Collectors Information Site  at http://www.stylophone.ws/index.html).  ‘Sounds poor and very poor plastic’, they say; but this Grand Piano Melophone seems like a step up from that, in sound and construction.

Here’s a brief example of the tones made by the Pacific Melophone:

Sufficiently Stylophone-like, I’m sure you’ll agree!  The two low notes beneath the Stylophone’s normal lowest note don’t come out too well, though.  I’ll have to see if something can be done about that.

Describing a Hong Kong made Stylophone, the Stylophone Collectors Information Site says ‘Problems were experienced by the Dübreq company regarding patent infringments, but licences were apparently also granted, so it is very difficult to categorise this particular model.’  Perhaps the same can be said for the Melophone: it definitely isn’t a Stylophone, but it seems to me reasonably built and with some very close similarities – was it somehow produced under licence, or just a clever copy?  If anyone has any further information, please let me know.

13
Mar
15

Guitar FXBOX – Part 2, the hardware

In my previous post on the FXBOX, I described a series of PureData patches used for guitar effects, and the need for a Foot Controller to operate it.

I happened to have a suitable case for this project – the remains of a previous mixer project which was never entirely finished. It was a large console-style case, about 18″ square, which I had already drilled with about 80 or 90 holes. The holes were too close together for all of them to be foot controller buttons, but about half of them could be used.

Outside of box DSCF0003

There were to be 4 sections to the controller, which would be: 1. Audio in/out and Audio to USB; 2. Audio to MIDI and MIDI to USB; 3. Keyboard Letters and Numbers, output via USB; and 4. Also via USB, Buttons and Potentiometers from a game controller.

*

1. AUDIO

The audio section was slightly more complicated than it might have been, as I’ve been using a twin-necked (6 and 12-string) guitar, and at some point intend to separate the output of the two sets of pickups.  For this reason, I added two audio input channels to the Controller.

The system basically works so that it can accept inputs either via a 6.35mm stereo socket or separate 6.35mm mono sockets, and can be routed either to a 6.35mm or 3.5mm stereo output, or two 6.35mm mono outputs. Each channel has a separate mono Send and Return, and there is stereo Send and Return covering both channels.

Audio DSCF0012

The 3.5mm output was included simply because this is the normal type of audio input socket on a laptop – which I was using to run Pure Data – and this would remove the need for a 6.35mm to 3.5mm adapter. Internally, there are connections to a Sonuus G2M Audio-to-MIDI converter – described in the next section – and an Audio-to-USB converter.

I took a chance on a cheap Audio-to-USB converter. I tried a few of the very cheapest type (99p on eBay), which worked OK, but I experienced too much latency, and these can only be used when the delay between playing and sounding isn’t important – on automatic or aleatory devices, for example. In this case, the next cheapest type (£2) seemed to work fine.

audio_usb

The intention of the Controller was that all four elements (the Audio to USB , the MIDI to USB, the keyboard numbers and letters, and the gamepad controls) would all be capable of output via a single USB socket. To accomplish this, I added an extremely reasonably priced (£3.95) 7-input USB hub. Given the number of items it would need to cope with, I got a powered one, which came with a 2-amp 5v mains adapter.

The inside of the box was going to be a bit like an enclosed pedalboard, and I simply velcroed this unit in position inside the case.

7 port hub

The hub was connected to a double USB socket unit – the type that would be fitted on a PC – with one socket connected to the type B output socket on the hub, the other one serving as an extra external input.

*

2. MIDI/USB

I added the MIDI section for two reasons: the first was that although MIDI implementation wasn’t really the point of this Controller, it could, I thought, come in handy for later applications, and be a convenient place to house my Sonuus G2M – a monophonic guitar-to-midi converter. The G2M, like the USB hub, was velcroed in place and linked up via internally-connected plugs.

G2M 27589983

Secondly, I’d successfully used a very cheap MIDI-to-USB converter in a previous project (‘A new use for USB keyboards‘), and decided for £3 or £4 that one could be included here. In this case, I didn’t even remove the outer casing as I had done the previous time, but simply shortened the IN, OUT and USB leads to fit and velcroed the unit to the inside of the case.

MIDI Inside box 1 DSCF0001

Audio and MIDI inputs would normally be via internal connections, but I added two 5-pin DIN sockets to the outside of the case. The first was for MIDI Out; the second, via a DPDT toggle switch, allowed input to the converter to be internal or external in case I wanted to connect a MIDI instrument or controller, such as my Behringer FCB1010, use another audio-to-MIDI converter, or decided not to use the G2M inside the case.

MIDI DSCF0012

*

3. LETTERS & NUMBERS

I had worked out for the previous project referred to above how to use the PCB from a defunct Apple keyboard as a means of outputting ASCII codes. The [key] function of Pure Data can be made to interpret and take action on these in any way required. I wanted to include this feature to help in using my looping program, Jesse Chappell’s Sooper Looper.

sshot6

As well as being controllable via MIDI, many of the Sooper Looper functions are controllable by input from the computer keyboard.  I wanted to include a simple system which would output some of the keyboard letters required to record, overdub, reverse and so on.

A 10×4 matrix would output all the letters in the alphabet, and the numbers 0-9, so I could put up to 40 buttons on the Controller (including a couple which represented punctuation marks), but I wouldn’t need anything like 40 buttons for this application.

I started confidently, as before, disassembled one of my collection of broken keyboards and took out the PCB.  It was very similar to the one I had used before: very wide, and with two USB input sockets on the ends – but it was a completely different make! So, I plugged the USB out cable into the computer, got the crocodile clips out, started up Open Office and began touching the matrix points together to see what letters came out – it had an entirely different layout from the one I’d used before!

However, after a certain amount of testing, it became clear that the matrix lines were essentially the same, but just in a different order on the board, which meant I could still get the 40 letters and numbers I wanted, and the pinouts on the sockets I planned to use (15 pin DIN HD) would still be compatible with the unit I had previously built.

In fact, it didn’t really matter about compatibility, as this would – at least as initially conceived – be a self-contained Controller unit, but I wanted to keep things consistent across my range of devices, and perhaps at a later date allow for an alternative or supplementary control unit to be connected to the Foot Controller.

I carefully connected the appropriate pins of the matrix to a ‘break out’ board, to which I connected a 15-way PCB header.

Apple PCB DSCF0004

This would make it a relatively simple job to connect buttons later.

*

4. GAME CONTROLLER

Again, I had used a game controller before, for the Theresynth/Cybersynth project, using the PureData [hid] function; but this time I needed to be more ambitious and use the joystick potentiometers as well as the buttons.

Of course, there are companies which produce USB controller modules, mainly for arcade controller enthusiasts, for example Ultimarc: http://www.ultimarc.com, and GroovyGameGear: http://groovygamegear.com.  The best value seemed to be the ZD (Zero Delay) Arcade controller, which is readily available on eBay.

Arcade Controller

I bought a couple of these two years ago at £8 each, but they seem to be even cheaper nowadays.

Good though they are, however, these units are limited to 12 buttons and two potentiometers.  Game controllers tend to have quite a large number of buttons – especially if you include the hatswitch buttons – and potentiometers on a single circuit board.

I needed 18 buttons, so I decided to use a game controller board for this part of the project.

There are a number of explanatory articles on the internet, such as this one: http://kevinreems.com/WorkShop/Joysticks//, and a lot of valuable information on this forum: http://forum.arcadecontrols.com/, as well as a few videos on YouTube. I like this one, which, although not captioned in English, is nicely visual: http://www.youtube.com/watch?v=9Y6ZqgT4Uk0.

Even Nic Collins’ classic book Handmade Electronic Music [http://www.nicolascollins.com/handmade.htm] has a chapter on the subject.

There are many different makes and models of gamepad, and one thing I’ve learned is that they’re all different – or liable to be different – in their electrical connections, so a certain amount of cautious experimentation is required to find out, for example, whether button connections are made to ground or some other voltage value in the circuit; if they’re arranged in a matrix; or if there’s a mixture of different systems. Sometimes this can readily be determined by looking closely at the circuit board and following the tracks around, sometimes it can’t.

So, if you’re reading this for hints on how to make the connections, use it as a guide to the type of thing you may need to do, but you may not necessarily be able to copy the steps precisely.

The other thing to note is that the connections on these PCB’s are usually very delicate, so you need to proceed carefully to avoid the narrow copper tracks coming away from the board.

As far as my gamepad was concerned, I used a Nyko Airflo, which was around £5 on eBay.

I removed the outside and an internal plastic piece which supported the two main PCBs and the fan which gives the Airflo its name.

Disassembled 2 IMG_1647

The idea was to reconnect the gamepad’s buttons to buttons on the FXBOX foot controller, so I detached the fan and looked for the button connections on the PCBs.

PCB 1 & 2 IMG_1650

Four of the 12 buttons were on their own mini-PCBs, connected by wires to the main board; the function of the wires was marked on the board, so I cut off the small PCBs and left the wires.

The various hatswitch connections and 6 of the remaining buttons were on the main board. These all had suitable spots in the copper tracks where it would be possible to solder wires.

The remaining two buttons were part of the joystick assembly on the second main board. It was easy to see the connections, and as the buttons were normally open (not connected), it would just be necessary to connect wires to the two sides of each one – or one side if the buttons all proved to have a common side, which is the usual practice.

I also needed to use the 4 potentiometers, two on each joystick, and wasn’t looking forward to de-soldering them, as I was anxious about damaging the tracks on the board. It doesn’t look too difficult on the videos, but I noticed on mine that there was small gap above the board where you could see the three legs of each potentiometer – the small ‘preset’ type – just enough room to insert a hacksaw blade and cut them off.   This is what I planned to do.

pots

First, as with the other devices in the Controller, I needed a much shorter USB out cable to connect to the hub, so I shortened the lead, but reconnected it before going any further, as this would be needed for testing.

The next step was to bring out the button connections to a ‘breakout’ board and find out exactly which ones I needed.

In most cases – perhaps all – I was sure that it wouldn’t be necessary to use 2 wires per button, as I had done with the Cybersynth; one side of the button connection would usually be Ground, and I hoped it would be possible to use one Ground connection for all of the 12 buttons.

This did prove to be the case, and I didn’t have the problem reported by some others of the unit not working at all without the joysticks connected.

I connected the 13 wires (one for each button + one for Ground) from the gamepad board to the breakout board, and a 13-way PCB header to give easy access to them.

The hatswitch connections looked as if they might be the same – except that there were 4 buttons, and I knew that 8 separate outputs are available from a hatswitch, meaning that 4 outputs were available from the 4 buttons individually and 4 outputs were available by connecting adjacent buttons simultaneously.

To make it easy to access these 8 outputs with 8 separate buttons, I connected diodes like this:

hatswitch-diodes-2

The connections at the top go to buttons in the Controller, and connections 1, 3, 5 and 7 at the bottom go to the 4 button positions on the circuit board; connections 2, 4, 6, 8 and 9 don’t need to be connected directly to the board.

This arrangement means that, for example, pressing Button 1 activates only Button 1, and pressing Button 3 activates only Button 3, but pressing Button 2 activates both Buttons 1 and 3 at the same time.

Only adjacent buttons are meant to be connected at the same time, which is why a hatswitch has 8 different outputs; but I discovered that connecting any two non-adjacent buttons on this particular board produced a ninth different output, recognised by PureData, which is why a ninth button is shown.

As a Ground connection was already available on the breakout board, I only needed 9 further connections for the 9 hatswitch buttons. This meant that 21 separate buttons would be available altogether.

*

The next task was to replace the two 2-axis joysticks with 4 potentiometers. Two of these would eventually be footpedals so that certain settings – volume and pan, for example – could be adjusted while playing.

I started by cutting through the legs of the existing potentiometers, as described above.  Once cut off, the potentiometers were easy to remove, exposing the three connections for each one.

Tracing the lines on the PCB, I could see that the ‘top’ and ‘bottom’ connections of each one were the same: only the middle pins had individual connections.

The bodies of the joysticks didn’t need to be removed from the board – and in fact were best left where they were, as some Ground connections from one part of the board to another appear to made through them.

I knew the potentiometers were likely to be more difficult to make use of than the buttons, but I was puzzled that I wasn’t able to get them working easily when I connected them to the board. For some reason they didn’t move smoothly from zero at one end to 255 the other as they were supposed to; on occasions they would return to zero and then refuse to move.

In the end, I read something that doesn’t seem to be mentioned much in articles on gamepad hacking, which seemed to be the root of the problem: joysticks are sprung to return to the centre of their travel, so a gamepad is expecting a midway reading on each one when it’s plugged in, and calibrates itself at that point to make sure the joysticks go back to the middle when let go. If potentiometers are used, and left at random values when the unit is plugged in, then the gamepad will get confused, try to calibrate itself wrong, and consequently fail to work properly – or at all.

The value of the joysticks in my gamepad was 100k, and they looked to be connected as voltage dividers, with the ‘top’ and ‘bottom’ tags all connected together, so, assuming these were +v and 0v (although it doesn’t really matter what they are) – I created a midpoint 50k from the top and 50k from the bottom (two 100k resistors in series = 50k). This would be connected to the centre tags of the potentiometer inputs to the board when the unit was turned on, the circuit would be calibrated, then the actual potentiometers could be connected and would correctly produce values from 0 – 255.

The writer of the article quoted above [http://kevinreems.com/WorkShop/Joysticks//] had a neat solution to this, using switched jack sockets, but I wasn’t able to use this method, as I wasn’t always going to be plugging into sockets. Instead, I connected the centre tags of the four potentiometer inputs to the centre tags on a 4 pole, two-way switch: this switch would be in the ‘off’ position when the unit was plugged in, which would connect the inputs to the ‘halfway’ voltage, enabling them to be calibrated, then when the unit was ready to be used the switch would be moved to the ‘on’ position, where the potentiometer inputs would be connected to actual potentiometers.

As a result, I ended up with a breakout board with 12 pins representing the 12 buttons numbered on the board, 9 pins representing the hatswitch buttons, 4 pins representing the 4 potentiometer outputs, and 3 pins representing +5v, 0v and +2.5v.

I also used 2 further pins for the game controller LED which lit up when the USB connection was made: I connected these to an LED on the outside of the case where I could see it and verify that the board was working.

That made 30 pins. Even when I calculated that I needed only 6 of the 9 hatswitch buttons, that still made 27 pins, plus 15 pins from the Apple keyboard PCB described earlier.

All the connections needed to be in place while the case was still open, so I needed to join all these pins on one side of the box where the circuit boards were to connectors on the other side of the box where the buttons were. To bridge this gap, I decided to use 40-pin ATA cables, normally found inside a desktop PC, which are inexpensive and compatible with the PCB connectors I was using.

ATA cables

These cables (as in the above picture) frequently have two separate connectors quite close together at one end. This made it easier to make connections not only from one side to the other, but also to special output sockets on the back of the case.  These could be used if alternatives were required to the buttons on the unit.

The 15-way socket on the back of the Controller has the same pin designations as my previous keyboard PCB-based project; the 25-way socket is a new arrangement, specific to the game controller:

Keybd & HID out DSCF0012

*

Finally, there was one downside with internal fixing of the Sonuus G2M ‘Guitar to MIDI’ unit – it runs off a PP3 battery: this would mean firstly that the ‘Battery low’ indicator couldn’t be seen from outside the case and secondly that the battery couldn’t be changed without taking the case apart. As this is held together with about 10 self-tapping screws, this would be too much trouble.

The main electrical supply was the the 5v adaptor that came with the USB hub, so I bought a small step-up voltage module for a couple of pounds to provide a 9v supply for the G2M.

voltage converter

I adjusted it to slightly over 9 volts, to make sure the G2M would be operated reliably and added a second power on/off switch for the 9v supply.

*

This is the almost finished base of the unit, showing the 7 elements.  All the connections are in place, except the power connector lead, which runs from connector 7 in the picture over to the power switches on the front of the unit:

Inside captioned IMG_1397

1: MIDI to USB

2: 7-port USB hub

3: Audio to USB

4: Apple keyboard PCB

5: Sonuus G2M, Audio to MIDI

6: Gamepad PCB

7: Power connector

This is the almost complete top section:

Top captioned IMG_1395

I gingerly put the two halves of the case together, and all the functions seemed to work, so I screwed it firmly together.

Now, with minimum use of the laptop keyboard, I was able to control the Looper with the buttons on the Top Panel:

Top Panel DSCF0009

and the FXBOX PureData program with the buttons on the Front Panel:

Front panel DSCF0010

I left space for additional button descriptions as the unit isn’t limited to controlling the Sooper Looper and FXBOX: in fact, it could be used to control any PureData patches which required [key] or [hid] inputs.

In addition to this, I had made provision on the front of the case for 4 footswitches which could duplicate the effect of any of the buttons on the panels:

Front DSCF0011

So far, I have just implemented two of the four possible: Footswitch 1 duplicates the ‘Overdub’ control in the Looper; Footswitch 4 duplicates the FXBOX ‘Freeze’ control.

I obtained some very nice momentary footswitches for only about £3 each from eBay.  They are apparently intended to operate tattoo machines, and have the advantage of coming with 1/4″ (6.35mm) standard mono jack sockets attached, perfect for this application.

tattoo switches

As for the footpedals, I haven’t implemented those yet.  When I do, I’ll describe this in a further post.




andymurkin

July 2018
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