Digit Freequencer

A non-quantised eurorack gate sequencer based on the arduino nano. The sequencer records gates from the pushbutton or the gate input and repeats them in a loop. The loop length is eight clock pulses (rising edge on the clk input), maximum 32 seconds, and can be reset by the reset button or a rising edge on the rst input.

The gates are recorded by measuring the time of the rising and falling edges from the beginning of the first step. The resolution is milliseconds, meaning the gates are not quantised to the clock. This enables a simple way to program more complex and swung gate patterns in a eurorack synth or to add some (more or less involuntary) humanisation to rythms - hence the “freequencer” moniker.

The seq toggle sends the input gates to the sequence (switch down), or alternatively to the auxilliary output without affecting the recorded sequence (switch up). Flicking the del switch up will make any input gate delete the sequence. The undo button deletes the last gate.

There is a clock divider mode (accessible by seq switch up and reset button hold while the module powers up) which enables internal division of input clock from /1 through /8.

It’s my first eurorack module and my first pcb fab experience and it was great!

Here’s a quick demo.

Code, schematic and gerbers etc is available under CC BY-SA 4.0 on github.

Sep 2020