This is a Eurorack Modular module. It is a CV Gate Sequencer. It is based on the design by Hagiwo. Hagiwo's original design is here and available to all. https://note.com/solder_state/n/n7c2809976698 The site is in Japanese, but Chrome will translate to English

I designed the faceplate and the pcb mount. I also modified the Arduino code and the circuit. I added a Gate, as the original design only had a trigger. My final module has 2 jacks for Gate, 2 jacks for Trigger, a Gate LED, a Trigger LED, a CV out and a Clock In jack. The module uses a ssd1306 display and a rotary encoder to control.

My version of the code was modified for the above. Also the code previous had a resolution of 4 for the encoder, but my encoders needed a resolution of 2.

All of the 3.5mm mono jacks seem to be slightly different dimensions for the black plastic. The actual metal jack seems to be standard. This stl is customized for the black jack that has the Metal shield wrapped around it as shown in the picture. If you use any other jack, you will want to measure and adjust the stl just slightly. The design is so that the jack is supported by the plastic walls of the print, on 2 sides of the jack. This keeps the jack from turning. You can move the circular hole a bit or adjust the thickness of the walls to get it to support other jack. I have included a picture of how I adjusted the fit for another similar jack.

Feel free to check my post on reddit and post questions there if you like; https://www.reddit.com/r/synthdiy/comments/11hcqt6/module_3_for_my_rack/

Code and details at; https://github.com/n9jcv/Eurorack-Modular