In whch yr hmbl svt gets some more sub-$10 smartwatches ($4 and $6.50 respectively) and takes them apart to see what makes them tick. Figuratively.

Turns out these things are based around some pretty decent hardware, much more so than the last LT716. Also, all three watches (these two and the LT716) use different CPUs! The expensive watch -- which was $6.50 when I bought it but is now $5 -- is actually pretty nice and might, with some work, be usable as a watch.

pvvx's PHY6222 firmware and tooling: https://github.com/pvvx/THB2
Tuya's page on the PHY6222: https://developer.tuya.com/en/docs/io...
PhyPlus' page on the PHY6222: http://en.phyplusinc.com/index.php/ha...
YiChip's page on the YC11xx family: http://www.yichip.com/yc11xx
Affiliate link to the $4 watch: https://s.click.aliexpress.com/e/_DFQ...
Affiliate link to the $6 watch: https://s.click.aliexpress.com/e/_Ddh...