Several years ago I bought a Baratza Virtuoso coffee grinder and I love it. The only thing that nags at me a bit is the fact that the mechanical dial timer is extremely imprecise and inconsistent. A long time ago I put marks on the case to label where to turn it to to get the exact amount I need for one Aeropress cup, for two or three cups in a Chemex, etc, but it's always off the ideal by a few grams. It seems I'm not the only person who shares this concern because Baratza upgraded the Virtuoso to the Virtuoso+, which has a digital timer. I don't want to throw away the terrific grinder that has served me so well for so many years just for that one feature, so instead I decided to upgrade it.
The motor inside the grinder is synchronous AC, so I need to switch an AC voltage. I don't like using mechanical relays on general principle, so I went with a TRIAC. I slapped one of those onto the back of a Raspberry Pi Pico (which I recently discovered and absolutely love), connected them with a small solid state relay, and shoved that inside the Virtuoso case along with an old 120VAC→5VDC power supply. I drew up and printed a mount to hold the MCU's button in place where the old dial used to be as well as a big plastic button that fits into the original hole. Over the next few days I'll tune the timer to get the 12g that I consider to be a single dose for an Aeropress or Chemex cup.
Schematics, source code, and CAD are available as always.