My $0 version: https://object.ceph-eu.hswaw.net/q3k-personal/5143b5491fca1100da596b14f68401a9a6977ff6b67ef2f6caa083817d1f451c.jpg https://object.ceph-eu.hswaw.

My $0 version: https://object.ceph-eu.hswaw.net/q3k-personal/5143b5491fca1100da596b14f68401a9a6977ff6b67ef2f6caa083817d1f451c.jpg https://object.ceph-eu.hswaw.net/q3k-personal/5143b5491fca11... Usually wrapped in electrician's tape. 1. NRF52 board from some scrap given by a friend, running forked/ported OpenHaystack firmware 2. AA battery holder from junk box 3. AA batteries from junk drawer If my math is correct, this should last until AA self-discharge, ie. around 10 years. Yes, it works with Apple's FindMy network. Yes, I've flown with it.