Here's a video and a picture of the final keyboard and a video of me playing it badly!
Details
The keyboard came with no controls or switches, not even an on/off switch. So I've added an on/off switch, a blue LED to indicate signal strength, a sustain on/off switch, a pitch pot with a switch below that has two modes, one chokes off when it get below a certain range, then the other mode has a capacitor wired in that smooths out the pitch control.
The pitch control also has sustain in it too so interacts with the sustain switch, and also the LDR.
The LDR (Light dependant resistor) basically wobbles the pitch when you move your hand over it, and also has a variable filter capacitor wired into the switch to make it more sensitive.
All the controls interact with each other providing a wide iteration of possibilities, didn't get them all in the video though.
Lastly I added an output jack so I can plug it into an amp or DI for the studio. One thing I didn't count on as I wired the output jack, is that the speaker becomes microphonic, so you can get feedback too when amped up. To me this is a plus, but in future ones I might do that differently, with some kind of switch or cut out feature when plugged.
Video
