GoKawiilEngineer builds battery-free NFC business card with animated LEDs and onboard MCU
A hobbyist designed a PCB business card that uses an NFC chip's energy-harvesting capability to power 21 LEDs and an ATtiny412 microcontroller, all without a battery. Tapping the card against a phone triggers an LED animation, drawing power solely from the phone's NFC field via chips like the NXP NTAG I2C Plus or STMicro ST25DV-KC that can route excess harvested voltage to external components. The creator built the project in about three months as a way to learn KiCad, and has published the full design files publicly.
GoKawiil's interpretation of the reporting above, not reported fact.
This project highlights an underused feature of certain NFC chips—routing harvested energy to external hardware—that could inspire cheap, battery-free interactive devices beyond novelty business cards. It also demonstrates how accessible PCB design tools and open sourcing let hobbyists push consumer electronics concepts that blend RF engineering with creative design.
- The card uses NFC-harvested energy to power an ATtiny412 MCU and 21 LEDs without any battery.
- Special NFC chips like NXP NTAG I2C Plus can route excess harvested voltage to external circuits.
- The full hardware design and code have been open-sourced for others to replicate or build on.
Hakko FX-888D Digital Soldering Station — Hand-assembling a tiny NFC business card means placing fine-pitch parts and 21 LEDs, and a temperature-controlled iron makes that far less painful than a plug-in pencil. The FX-888D is a workshop staple for hobby PCB builds, with adjustable temperature and a wide range of swappable tips for everything from LED pads to the MCU. Perfect companion for your first KiCad project turning into real hardware.
See Hakko FX-888D Digital Soldering Station on Amazon → Affiliate link — we may earn a commission on purchases, at no extra cost to you. Product picked by AI based on this article; it is not a tested recommendation.Source: wilsonharper.net — Wilson Harper, 2026-08-28
Published there as: “Show HN: NFC Energy-Harvesting PCB Business Card with an MCU”
Read the original report → The summary and analysis above are GoKawiil's own, written from reporting by the source above. Facts and quotes belong to the original publisher.