Mosha Eurorack Modules #7: Drum Sequencer

 

The drum sequencer is a 6 HP module that sequences drums. It was intended for the drum module, but could be used for anything that needs a fixed pattern of gates over a 15 or 16 step period. There are 8 outputs, each with a different rhythm. There are lights behind the jacks that show the pattern before a cable is plugged in. This makes it clear which plug is which pattern, but avoids additional power use while the pattern is used.

The patterns themselves are chosen using a switch. In the middle position it will use the standard 16 beat patterns. In the down position it will use the standard 15 beat patterns. In the up position it will randomize the patterns once, and then use the randomized patterns. This pattern is stored in memory, so after a restart the pattern will remain the same.

There is one input, which is the clock. This determines the speed at which the beats happen. Beats can happen on clock up and on clock down, which means that the outputs can be twice as fast as the inputs when needed.

There is an ICSP connector at the back that allows the rhythms to be changed. The circuit is exceptionally simple: it is a 16F684 and all gates are connected using a 1k resistor. It therefore relies on the diodes in the PIC16F684 to prevent damage, but this generally isn't a problem.

The source code is available here.