Could use an optical sensor like the Timex Datalink watches from the 90s[1]
Could set the earrings on a phone screen and transfer the patterns over. Sounds like a fun project.
Could set the earrings on a phone screen and transfer the patterns over. Sounds like a fun project.
Here's a (tiny) demo of this for my PCB business card project from years ago [1]. If IIRC this proof of concept was as simple as using a phototransitor on a GPIO connected to the UART peripheral with a very low baud rate.
[1]: https://www.matt.egan.me/entry/electronic-business-card-pt3#...