In order to integrate my old Acorn RISC PC into my KVM switch setup, I have been looking for an adapter to connect USB input devices to PS/2 sockets on the computer. Preferably in such a way that you can also do this with just one USB port to which a hub is connected. My KVM switch only passes the USB devices to the computers with one cable.

There are ready-made adapters, but they are quite expensive. That’s why I’m now trying to build such an adapter myself, based on an ESP32-S3. The ESP32 should actually be overqualified for this task, but this way I still have free capacity for additional ‘gimmicks’ such as a web interface, firmware updates over-the-air, etc.

I loosely soldered the hardware on a circuit board:

I have made the source code and further details on the wiring available on Github.