Procedural melodic sequencer (12HP)

Based on:
Tuesday by This Is Not Rocket Science.

interactive version

Created from the design files that TINRS kindly made available, with a custom FR-4 panel.

Build notes

There's a few flat no-leads packages on this board that pretty much need hot air or reflow assembly. I highly recommend the Segger J-LINK for flashing the firmware, haven't had much luck with other programmers.

The original manual leaves out a few details on calibration:

  1. Boot up the module while holding down the scale button. The ticks and beats LEDs will start flashing.
  2. Press the ticks button to enable calibration of the VEL output (and not NOTE as the manual claims).
  3. The output will produce a voltage based on the position of the ! potentiometer:
    • When CW the output will be close to 1V, and can be fine-tuned using the X potentiometer.
    • When CCW the output will be close to 3V, and can be fine-tuned using the Y potentiometer.
    • When around 12 o'clock the output will cycle at ~30 Hz between the two previous states.
  4. I find it easiest to tune the top and bottom levels separately (! fully (C)CW) through an already-calibrated VCO or voltmeter, if the output is cycling you'll need a precision oscilloscope.
  5. Tune the lower voltage to exactly 1V, and the upper to exactly 3V. Hold down the ticks button for 2 seconds to save the calibration.
  6. Repeat steps 2 - 5 using the beats button to tune the NOTE output.
  7. Press algo to exit the calibration procedure. All done!