Badge Holder

The need

Graduation forums are packed with students. To stand out, I decided to craft an electronic badge holder inspired by DEF CON badges. It holds a standard business card yet flashes skills in hardware, firmware and 3‑D design.

  • Eye‑catching LEDs : 24 WS2812B around the frame.
  • Brain : ESP8266 flashed with WLED 0.14.
  • NFC : tap the badge → opens my portfolio (HTTPS + GPG fingerprint).
  • Runtime : ~6 h on a 2000 mAh Li‑Po at 25 % brightness.

Bill of Materials

All components are cheap, easy to source:

  • 1× Wemos D1 Mini V4 (ESP8266)
  • 24× WS2812B LEDs (cut from 144 LED/m strip)
  • 1× Li‑Po 604050 – 2000 mAh
  • 1× TP4056 USB‑C charger / 5 V boost
  • PETG translucent filament for the case

Schematic

schematic

Data on GPIO2 (D4). Brightness limited to 350 mA in WLED to protect the boost converter.

3‑D printed case

The design is a two‑part sandwich: translucent front window, opaque back shell. Slide the core out to swap front plates or access electronics. M3 brass inserts hold everything together, and a 1 mm recess diffuses the LED ring.

render interior

Firmware & palettes

Flash WLED:

esptool.py write_flash 0x00000 WLED_0.14.0.bin

Then set LED count to 24, max current to 350 mA and enjoy 100 + built‑in palettes. Demo of “Palette 28” below:

palette demo

Future ideas

  • BLE iBeacon for presence in Home Assistant.
  • E‑Ink front plate for daylight readability.
  • Qi wireless charging pad behind the badge.
germain@godef.be
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