openmarquee

Wi-Fi firmware for classic Pro-Lite LED marquee signs (<ID01> serial protocol). A Wemos D1 Mini (ESP8266) + MAX3232 bridges the sign's RS-232 port to MQTT, an HTTP API, and a phone-friendly web UI with presets and OTA updates. Turns a 20-year-old scrolling sign into a networked marquee — no vendor software, no IR remote required.

(photo slot — installed sign + D1 Mini in place)

Status

Stage 1: bench probe. The transparent host↔sign bridge sketch in firmware/bridge/ is scaffolded and ready to flash. Nothing downstream is trusted until <ID01><RST> produces CHECKING on the real sign (the Stage 1 gate). Application firmware (MQTT / HTTP / UI) is held until that gate passes.

Hardware

• Sign: Pro-Lite Banner-Lite PL-BL v1.0, RG bicolor (red/green/amber)
• MCU: Wemos D1 Mini (ESP8266EX, CH340 USB-serial)
• Level shifter: MAX3232 (mandatory — sign TX is true ±12 V RS-232)
• Sign UART: bit-banged via SoftwareSerial on D5 (GPIO14) = RX and D6 (GPIO12) = TX. The ESP8266's single hardware UART is already occupied by the CH340; software UART at 300/9600 baud is perfectly adequate for this protocol.
• Power: ESP 5 V from the sign's internal 5 V PSU rail

Full pinout, wiring, and power warnings: hardware/README.md.

Planned features (v1)

• MQTT (sign/set/#, retained sign/state/#, LWT on sign/availability)
• HTTP API — GET /msg?page=A&text=..., curl-trivial
• Phone-first web UI with presets stored in ESP flash (LittleFS)
• OTA updates (browser /update + ArduinoOTA dev flow)
• Cut from v1: timers UI, <Gx> graphics editor, auth, HTTPS, multi-sign

Single internal state model; MQTT, HTTP, and UI are thin clients of one command handler. Web UI has no privileged path — it calls the HTTP API.

Repository layout

firmware/    arduino-esp8266 sketches (configure/make wrapper around arduino-cli)
web/         Web UI source (pre-flash inlining)
hardware/    JP3 pinout, MAX3232 wiring, power map, warnings
PROTOCOL.md  <ID01> command table with verified-status column

Building the firmware

Requires arduino-cli. No PlatformIO, no Arduino IDE.

cd firmware
./configure --port=/dev/ttyUSB0     # or COM8 on Windows, adjust as needed
make deps                            # one-time: installs esp8266:esp8266 core
make flash monitor

Runtime baud switch in the bridge: send ~<baud>~ on the host (e.g. ~300~) to reconfigure the sign-side SoftwareSerial without a reboot. Default sign baud 9600 8N1; host↔ESP console is 115200 8N1 (CH340).

License

MIT. Original project: https://github.com/OriginalOC/openmarquee.