Hardware

A miniature traffic light, battery-powered, with a small e-ink sign. Open hardware – and still in development.

In development. This is the plan. A breadboard prototype from ready-made modules comes first, then the circuit board and the enclosure. Until the light is ready, a smart lamp in Home Assistant can stand in for it.

The plan

• Three chambers – red, yellow and green, like on the road. Single-colour LEDs, dimmable, readable from the end of a long hallway.
• ESP32-C6 with Wi-Fi and MQTT. Light sleep keeps the connection, so a change reaches the light within about a second.
• 1.54″ e-ink sign, 200 × 200 pixels: until when, what comes next, battery.
• 18650 cell with safe charging electronics; USB-C for charging and for permanent power.
• 3D-printed enclosure (OpenSCAD) shaped like a miniature traffic light with visors, and a removable mount – magnets for steel posts and railings are planned.
• Circuit board in KiCad, assembled by JLCPCB, with production files built by CI.

Firmware

ESP-IDF in C, built for battery operation: the LEDs keep running in light sleep, and when nobody’s in the office the light sleeps deeply and checks in every few minutes. Flashing and Wi-Fi setup happen in the browser (ESP Web Tools and Improv), updates over the air with automatic rollback. For builds on mains power there will be an ESPHome example – bring your own lamp.

Roadmap

1. Breadboard prototype: firmware, LEDs and lens test, e-ink, current measurement, battery operation.
2. Circuit board and enclosure v1.
3. Polish: battery life, e-ink layouts, Stream Deck, web flasher, updates over the air.
4. Release – with OSHWA certification.

The breadboard parts list and the full hardware notes are on GitHub.