Circuit Bent Fun Years Keyboard

Yesterday I decided to take a break from In The Crystal Palace and mess around with some new toys instead. On Saturday I picked up some used kiddie electronics at the Salvation Army thrift store, including a Fun Years keyboard. A cheap Chinese knockoff, this toy keyboard has some interesting features, including several rhythm settings, a record button, and a "one key note" button. The electronic guts are what you would expect to find - a "black blob" IC common to most inexpensive electronics, and a separate amplification chip. To change the pitch I removed the timing resistor & and replaced it with a 500k potentiometer. I also added two photoresistors so that the pitch can also be altered by light/shadow. I also poked around the amp chip and found some nice distortion and feedback bends. Finally, I added a 1/4" output jack.

Overall interior view w/ modifications

View of pitch control w/ 500k pot & 2 photoresistors. Photoresistors are hot-glued inside a wood block which is hot-glued to the front interior case.

Exterior view of pitch controls. Photoresistors are above the knob.

Overall exterior view w/ modifications. The distortion/feedback bends are manipulated by the two knobs at the right.

I'm happy with how this project turned out. The photoresistors add an additional level of interaction and playability, and the distortion/feedback bends add some teeth to the audio. For example, there's a cheesy "Mandolin" setting that repeats the same note as long as the key(s) is held down, but slowed down & distorted has an ominous, driving Krautrock vibe.

Here's a short video clip:

and... here's the same clip but with the video scrambled using Audacity, slowed down 90%, and edited in length to fit original audio: