The goal here was to have an open-source device that could talk to your iPhone.
It started as a school project called AirPark. You can see our demo video below:
I turned our demo one into a PCB, which probably didn't work because I didn't know how to program an esp32 properly.
I made another version, dipping the circular shape.
I got to a point where I wanted it to have a proper battery. I did the right thing by making an evaluation board, but in hindsight I should have just used the same coin-cell battery as the airtag.
The project picked up again when they made some solid progress that can be found on this github page.
I think the thing that was missing was the application. The application should have driven the design.
A big problem was that there had to be middleware living on a specific MCU in order to talk to an iPhone. The tags can nicely talk to each other, so why wouldn't I just do that?