This is a little toy I built for my nephews’ birthday. I never drew a schematic for it, but here is the idea:
There are three percussion sounds. Two of them (the ‘kick’ and ‘snare’) are two variations of the famous ‘Space Rockers’ variety – probably the easiest percussion circuits to build.
These are triggered from an 8 step CD4017 based sequencer (look up ‘Baby 8 Steps’ for more info). The tempo is determined by the clock speed, which is based on the 555 timer.
The third sound (that clicking eights) is actually a pretty silly hack. What it is is the clock pulse, which I’m using as another sound source. I got this idea from Thomas Henry’s Impact Generator, which he in turn borrowed from Craig Anderton’s ‘Hip Bass Drum’.
Finally, I wanted some kind of a lead sound to be played along with the rudimentary rhythm. I used another 555 timer, timed to audio frequencies, and slapped a photo resistor instead of a timing resistor, and viola – Oron’s Box was ready.