Tuesday, 16 August 2011

Miniature playable synth

While waiting for the boards from PCBCart to arrive, we decided to look at other miniature instruments for the range.

Of course we'll need a miniature drum kit, for laying down the beats, and a bass guitar for laying down the grooves, will be more-or-less the same as a guitar (same functionality, maybe a bigger beefier shape). We've already made up a simple drumkit prototype, using some piezos and an existing miniature drumkit bought off eBay.

the gold coloured disks mounted under each drum skin are piezo tranducers, connected to digital inputs on the PIC microcontroller

What we need now is to manufacture the 'kit from scratch, now we've proved that the concept works. That can wait until we're visiting the local hardware store and can investigate the diameter of different plastic tubing! Another instrument we've yet to have a go at is a miniature synthesizer. There's a debate about which style to do first - a Moog, a Roland or a Yamaha Keytar?

At the minute it's not important - we're focussing on the functionality; the enclosure can be designed later! Here are some photos of the early synth development....

Rather than mess about with hinges and moving parts, we've just made the keyboard out of a series of "sprues", connected to a thick bar along the top. The idea is that there should be enough flex in the acrylic to allow the user to press the acrylic keys onto a series of soft-touch tactile push-buttons mounted onto a PCB underneath. These key presses will simply be digital inputs, allowing true polyphonic sound to be achieved.

Our miniature synth will have 17 keys, starting at middle C.
Why seventeen keys and not any other number? I wish I could say it was because of the number of available inputs or some other technical reason, but the truth is we all watched classic 80s synth clips on YouTube and after seeing how to play Axel F decided that 17 was the minimum number of keys required!

Whether the 18F2455 will have enough inputs for what we're trying to do (there will be other buttons such as pedal sustain, LED outputs and so on) or whether we'll need to move up to the bigger 40-pin 18F4550 still remains to be seen.......