Keyboard Builders' Digest / Tools
c!n tester
Aroum's c!n tester is a tool designed for testing Pro Micro-like microcontrollers: verifying pin functionality before soldering.
Published November 12, 2025
Published by aroum, the c!n tester is a dedicated hardware and software solution designed for automated functional testing of Pro Micro-like microcontrollers. Its primary goal is to provide a fast and reliable way to verify basic pin connectivity and functionality before deployment.
After a lot of tinkering and testing, I’m happy to announce the official release of c!n tester — a small but handy tool for checking microcontrollers before soldering them into keyboards – aroum2.
Cheap MCUs sometimes come with dead pins, and discovering that after assembly is a nightmare. c!n tester helps prevent that by verifying all pins in advance through a simple GUI.
Features
The tester board uses two controllers: a master (which runs the tests) and the target MCU (the one being tested). Everything you need – PCB files, case designs, firmware, app binaries, and full source code – is available on GitHub.
The application is built and tested on Windows 10/11 and Fedora 41, with macOS support coming soon. Documentation is still in progress, but the project is already quite usable.
Resources
Published on Wed 12th Nov 2025. Featured in KBD #201 (source).
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