More fun with 555 timers

I converted the blinky circuit we are doing at the workshop into a little Theremin-esque analog synth. There is an on/off switch (the photoresistors dont turn ‘off’ enough to modulate the volume directly, unfortunately), a frequency doubler switch (adds more resistors to the second half of the timing circuit), a volume knob and the light-sensitive photoresistor that you control by waving your hand over it. Close up of the circuit here.

Update: I mounted it all into a box, same guts inside..