Just an exploratory question here:

I cleaned up and started using a former Starbucks Mazzer Major a few weeks ago. (Thank you very much, Ilya, for your excellent guide!) The doser microswitch, of course, came out and stayed out after the mod. After doing some reading, turning the grinder on/off using doser clicks and the flap, and continuity testing a few switches, I understood that the grinder works as follows:

- Turn on when switch is turned to "Start"
- Stop when grinder exit flap clicks up: in circuit terms, the switch, normally a short, opens
- Start grinding after 12 doser thwacks, see step 2 above for next stop

Without the flap in the grinder or the microswitch under the doser (counting thwacks), I have a short between the terminals where the flap switch was connected and an and open (removed wires) where the counter switch was connected.

Pending confirmation of required voltages/currents, this sounds like it's just asking to be part of some kind of Arduino-based timer mod (with a few SSRs or transistors to keep the Arduino's signal pins away from line voltage).

If I can get a wire to the "Start" position of the switch, the Arduino will "know" when the grinder starts, and then all I need is to send a signal to ground (to trigger a relay/SSR to open where there would have been the flap switch) when the time is up.

Thoughts? Does this make any sense?

(To answer the inevitable question: the idea came up because I'm planning to get an Arduino involved in my Elektra machine's operation, so why not link it into the grinder as well? And much like with the Elektra, I would do this just... because!)

I can most definitely help you with the coding.. But I can be of 0 assistance with the hardware.. I will be following this thread closely as I'd like to similar to my 220v grinder as well.

Sounds like a super cool project.

J