While looking for something else, I found the old sample AVR processor I got at a trade show.


This thing is about as powerful as an early Apple][ computer. When I got it I connected it to some fine wires salvaged from a power cord and was able to read the device signature. I may have some even smaller ones somewhere.

Downside is they need about 2.7v to run although I think the brownout can be set to 1.8. Not sure how small a charge pump can be.

Went through that pound of mostly fake chronograps I got from goodwill, So I do have some movements I can use for testing.

Curious that the decent stuff like Omega and Heuer do not sell for the low scrap prices the Fosil, MK, and DKNY watches sell for.

 

I remember doing stuff like that to my old C64 -- adding a 2nd SID chip was the first. Then soldering an extra processor to my Nintendo to play offshore games. Building SIPPs as my afterschool job in High School. Slotting in math co-procs to my 386s. Good times!

 

I remember having to cut a trace on the circuit boards of 1541 drives to permanently change the drive's device number so I could use more than one disk drive!

 

There are some 3v Lithium coin cells that may fit into the original 1.55v battery cage, if your purpose is to use the controller in place of the original chip. The smallest I know of a 3v lithium coin cell is CR1025, 10mm diameter and 2.5mm thickness, compared to a 344 silver oxide with 11mm x 3.0mm.