diy projects
This NFC Business Card Lights Its LEDs With Borrowed Phone Power
Kevin Tang's PCB business card lights up with no battery on board, pulling about 5 mA from the phone's own 13.56 MHz NFC field.
diy projects
ATtiny816 PCB Business Card Runs 21 LEDs on Harvested NFC Power
No battery, no charging port. This PCB business card harvests power from your phone's NFC field to run an ATtiny816 and light 21 Charlieplexed…