Andromeda Space Rockers MK-1 Analog Drum Machine Kit

This was designed as an experiment of making the most minimal drum machine possible using analog circuitry.  Beyond that goal, the design also includes a new feature, IR Sync, which allows a group of these units to all synchronize together and play at the same tempo automatically.  Although the sound of one Andromeda Mk machine alone is simple, a group of them together can play more complex rhythms.  The complexity of the patterns is multiplied with each additional unit that is added to the network.  A maximum of 12 units can be connected in a chain.

The Andromeda Mk-1 analog drum machine has a minimal sequencer with sixteen preset patterns, selectable by the red switch block.  The pushbutton restarts the patterns.  This feature allows you to shift the timing of the rhythm when synchronized with other Andromeda Space Rockers instruments.

The sound of the Mk-1 is from a pair of damped sine wave oscillators, which are triggered simultaneously.  The oscillators are reffered to as “X” and “Y”.  Their pitch is controlled by the photocells AND the capacitors labeled X1,X2 and Y1,Y2.  The capacitors control the overall range of pitches that it can play.  Larger value capacitors here make lower pitches.

The square grid of holes is called the Personality Center.  You can use it to add additonal circuitry to your Mk-1 to change its character.  I will publish the Personality Center mods as soon as I get a chance.