I’ve had this keyboard done for quite a while. I decided to go a different direction by using predominately touch areas to patch the 555 oscillator IC instead of switches which I did not have lots of at the time. The unit does not really play unless the two screws on the right are shorted by skin. Photocells and a single knob controls the speed of the 555. The right switch controls 2 of the LFO speeds by substituting capacitor values. The Left switch patches ramp or square wave. The range of sounds is very extensive even from such a small and simplistic unit. Positioning of hands does play a big role in what sounds come out. Feel free to watch the video or peek the gallery of build shots.