Here’a a little mod of a drum machine that I have made. The Boss DR-110 is a nice old analog drum machine without midi or control of the drum sounds. So what I’ve done is giving it MIDI, so that I can trig each drum from my DAW, and I have bent the circuit a bit so that I can control various parameters of the drums.
So what I can control is kick decay, snare snappyness, closed and open hitat decay, clap filter and clap decay. Each of knobs control a variable resistor, the resistor is routed with two cables via the dsub 25 connector, then the cables are soldered to the board so that the variable resistor replaces a fixed resistor. If you google you’ll find lots of mods, just try them out.
As for the midi I have used two IC chips called 4066. They are like voltage controlled push buttons, and are available from your electronics peddler. So I have solderd two wires from each of drum buttons on the drum machine, they go to two pins of the 4066, and then, when the arduino recieves a midi command it sends voltage to the pin that closes the circuit for the two pins. Viola, the arduino presses the button for you.
So, how does it sound? Well it’s not an 808, but it’s quite charming and very drexciyan. The hihats are awesome, the kick, claps and snare are nice.
I’m too lazy to post circuit and arduino source code here, but just honk if you want some advice for doing a mod yourself.