I have a keyboard I bought in 2020 called the Makerdiary M60 keyboard. It runs Python, and over the years I've coded in various functions. But it was somewhat buggy, and the upstream firmware was never upgraded.

I love the hardware because it's the only keyboard I've been able to find that keeps a live Bluetooth connection and lets you toggle back and forth between USB and Bluetooth instantly using only a keyboard shortcut. That means you use two computers, and switch back and forth as fast as you can type. Years ago I also added a feature that changes the backlight color based on the active connection, so you can instantly tell which computer your typing will go to. I haven't been able to find any other keyboard that's quite as nice.

Lately I've spent weeks using an LLM to update the extremely old keyboard firmware to the latest firmware of its components (e.g., Circuitpython, the BLE firmware, the boot loader) and implementing all of my dream keyboard features that I never had the gumption to spend hours implementing pre-LLM. I finally resolved years-old bugs, and I added things like layer-based backlighting (so that the individual keys with relevant functions are lit), a better battery gauge, better sleep/suspend timing, backlight calibration, better debounce, and so on.

I've also upgraded the hardware and added batteries to each of the keyboards (I have three of these, one at home, one in the office, and one for travel).

It has been a very satisfying project, finally scratching a years-old itch.