This build is an intermediate level build that contains surface mount components, and is not recommended for absolute beginners. If you are a beginner, it is recommended that you build something simpler before starting this project.
Note that the development board (Adafruit Pro Trinket) used in this module comes pre-programmed when purchased from Thonk.
Do this before building this module:
Check that you have all components.
Gather all the tools needed (see lists below).
The tools needed for this build are:
Soldering station or soldering iron.
High quality solder (lead free recommended).
Fine tipped side cutters.
PCB holder (makes life much easier).
A fine grade file (for finishing off cut header edges).
10 mm hex socket covered in masking tape (for tightening nuts).
Knurled Nut Driver Tool (for tightening jack socket nuts).
Got everything? Let’s get on with it!
6. Switch, jacks sockets and potentiometers
7. Adafruit Pro Trinket 5V
8. Power Header
10. Powering up
First, make sure that the Pro Trinket is seated in the correct orientation on the PCB (USB socket facing downwards). Then connect a 10-pin eurorack power cable to the power socket (MAKE SURE THE ORIENTATION IS CORRECT!) and attach the module in your eurorack case. Push the LOOP switch and see if the GREEN LED is turning on. To test the module, connect an LFO to the TRIG input and a synth voice to the CV/GATE outputs. Increase the probability to start generating notes. The module should now be generating random melodies, although the notes are probably not in tune.
To calibrate the CV output, hold the SHIFT switch while powering on the module, and hold it until the yellow LED flashes twice. ODDS is now in calibration mode. To calibrate, set the % knob to the leftmost position. Connect a multimeter measuring DC voltage to the CV output. Adjust the CV OFFSET trimmer on the PCB until the multimeter reads 0.00 Volts. Now set the % knob to the rightmost position. The multimeter should read 6.00 Volts. If it does not, adjust the CV GAIN trimmer until it does. Redo this procedure a couple of times until both values are correct. Connect an oscillator to the CV output. Sweep the % knob to confirm that the octaves sound correct in pitch. To exit calibration mode, power off your case and power it back on without holding the SHIFT switch.