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.