This article introduces "Nomech mini," a 4x4 capacitive touch board designed as a low-cost monome alternative. Built with an Atmega32u4 microcontroller and back-fire LEDs, it utilizes a top acrylic layer as a dielectric for accurate touch sensing. The project is open-source, available on GitHub in various formats (schematic PDF, BOM CSV), and licensed under CC-BY-SA-3.0. The author plans to potentially scale the design to an 8x8 grid if this prototype succeeds.
Parts used in Nomech mini:
- Atmega32u4 microcontroller
- Back-fire LEDs
- PCB (Printed Circuit Board)
- Top Acrylic Layer
So this is a 4×4 projected capactive touch board using Atmega32u4 and back-fire LEDs for each button. I want to send the gerbers to Seeed sooon so any advice/feedback is very much appreciated.
It fits SoB 100x80mm but the top acrylic will sit right on top of the PCB as the dielectric properties of whatever is touching the electrodes matters a lot.
If this works well then I might scale it up to 8×8. I want it to work as a cheap monome replacement without using mechanical buttons; hence the name “nomech”.
This is designed using KiCAD.
Everything is licensed CC-BY-SA-3.0
For more detail: Nomech mini, a 4×4 capacitive touch button grid
- What is the primary function of the top acrylic layer?
The top acrylic sits right on top of the PCB to act as a dielectric because the dielectric properties of whatever touches the electrodes matter a lot. - Can I scale this design to a larger size?
Yes, the author intends to scale it up to an 8x8 grid if the 4x4 version works well. - What software was used to design this project?
This project was designed using KiCAD. - How can I access the project files?
Everything is available on GitHub as a zip file, with a schematic in PDF format and a bill of materials in CSV format. - What license covers the project files?
Everything is licensed under CC-BY-SA-3.0. - Does this project use mechanical buttons?
No, it is designed to work without mechanical buttons to serve as a cheap monome replacement. - What are the dimensions of the PCB?
The PCB fits within SoB 100x80mm. - Why are back-fire LEDs used in this design?
Back-fire LEDs are used for each button in the 4x4 projected capacitive touch board configuration.
