NavList:

The Sensor Watch community has an active Discord channel and they are very helpful. Another member will look at my F-91W that is either a very good fake, or they have slightly changed the white plastic mount. I have become much more of an expert in cheap Casio watch fakery than I wanted to be! I found a slightly different model, a W59 that is 50m waterproof, in a draw at home.

That does seem to work. Now back to software, I have compiled standard firmware and ran it in the emulator. So I have the "toolchain" working. Also NavList members will be able to try this thing out without hardware hassles. Next I make a firmware prototype. At some point I will check I can flash firmware on a Sensor Watch board (micro USB connector and appears to PC as a USB drive).

I will post here again when I have a prototype firmware. If anyone wants to follow technical details please join the Discord discussion. Showing an interest might encourage others to help as well.

In anticipation that I might succeed you might be on the lookout for a genuine Casio F-91W. Thrift, stores, jumble/garage/car boot sales, flea markets etc. Older ones are more likely to be genuine and older fakes at least easier to spot.

Bill