What the card does
The card is exactly what it sounds like: a business-card-sized PCB with an NFC antenna and a microcontroller. When you tap it against a phone or any NFC reader, the field powers the chip, letting it transmit data. No battery, no charging, no moving parts. The developer didn't share detailed specs in the post, but the concept is straightforward — a self-contained, passive device that can carry a small payload.
