
Front mcu db64
stuperbad/LED-Watch
A round LED wristwatch: 132 small LEDs (12 hours, 60 minutes, 60 seconds as three concentric rings) driven straight from an AVR microcontroller, with an accelerometer to wake it.

Open-Source Active PCB Business Card Powered by NFC
Business Card v2 is an open-source printed circuit board by WiHarper, from the WiHarper/nfc-card repository on GitHub. It is a 2-layer board of 85.4 × 54.1 mm with 39 parts on 33 nets, routed with 476 tracks and 38 vias.
It is built around the NT3H2111W0FHKH, XL-1608SURC-06FJ and DMP21D0UFB4-P, with the XL-1608UYC-06FJ among its other parts. Its parts include 22 diodes, 8 resistors, 4 capacitors, 2 ICs and 1 transistor. It belongs with the radio and wireless boards and the AVR (ATmega, ATtiny) boards of this library.

Like most business cards, this one doesn’t have a battery. When it’s tapped against a phone, though, 21 LEDs start an animation, powered just by NFC.
Find more information at wlsn.ee/nfc.
hardware/ - KiCad 9.0 schematic files/PCB layout files and 3D modelssoftware/ - firmware and KiPython scriptgallery/ - photos/video of cardThe ATtiny is flashed over UPDI; its clock speed should be set to 1 MHz. The NFC chip is formatted and written using NXP Tagwriter. Energy harvesting is enabled by default, and it is easy to add vCard records or a website link.
| Qty | Value | Footprint | References |
|---|---|---|---|
| 20 | XL-1608SURC-06FJ | JLCImport:XL-1608SURC-06FJ | LED1, LED2, LED3, LED4, LED5, LED10, LED11, LED12, LED13, LED14, LED15, LED16, LED17, LED18, LED19, LED20 +4 |
| 5 | 100 | Resistor_SMD:R_0402_1005Metric | R1, R4, R5, R6, R7 |
| 2 | 100n | Capacitor_SMD:C_0402_1005Metric | C2, C4 |
| 1 | 1.5p | Capacitor_SMD:C_0402_1005Metric | C1 |
| 1 | 100k | Resistor_SMD:R_0402_1005Metric | R2 |
| 1 | 10u | Capacitor_SMD:C_0402_1005Metric | C3 |
| 1 | 2.2k | Resistor_SMD:R_0402_1005Metric | R3 |
| 1 | 220 | Resistor_SMD:R_0402_1005Metric | R8 |
| 1 | ATTINY816-MNR | JLCImport:ATTINY816-MNR | U1 |
| 1 | Antenna_Loop | Custom_RF:Antenna V3 | AE1 |
| 1 | Conn_01x03_Pin | Custom_Connectors:Offset UPDI | J1 |
| 1 | DMP21D0UFB4-P | JLCImport:DMP21D0UFB4-P | Q1 |
| 1 | NT3H2111W0FHKH | JLCImport:NT3H2111W0FHKH | U3 |
| 1 | TPESD8LS5_0CT5G | JLCImport:TPESD8L3_3CT5G | D1 |
| 1 | XL-1608UYC-06FJ | JLCImport:XL-1608UYC-06FJ | LED22 |

stuperbad/LED-Watch
A round LED wristwatch: 132 small LEDs (12 hours, 60 minutes, 60 seconds as three concentric rings) driven straight from an AVR microcontroller, with an accelerometer to wake it.

tscircuit/rp2040-lipo-charger
Rechargeable RP2040 controller with USB-C, 1S LiPo charging, battery monitoring, and an OLED interface


nushackers/hnr26-badge-quacknroll
Hack&Roll 2026 "Quack & Roll" badge source files, for both hardware and firmware



ElectronicCats/badge-dragonJar-2025
¡El badge oficial de DragonJarCON 2025! Un dispositivo NFC programable con pantalla OLED, múltiples LEDs y un reto de hacking integrado. Diseñado para la comunidad de DragonJar

It measures 85.4 × 54.1 mm and has 2 copper layers, 0.79 mm thick.
39 parts, built around the NT3H2111W0FHKH, XL-1608SURC-06FJ, DMP21D0UFB4-P and XL-1608UYC-06FJ. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
From the WiHarper/nfc-card repository on GitHub, at the commit this page was made from: the board is hardware/Business Card v2.kicad_pcb and its schematic hardware/Business Card v2.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Its repository states no licence, so its author keeps all rights: ask WiHarper before reusing the design.