Public Access
94 lines
5.4 KiB
Markdown
94 lines
5.4 KiB
Markdown
# Flipdot Display
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Firmware for an 84 × 19 Brose flipdot display (three 28 × 19 panels) that runs as a
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Home Assistant–controlled clock.
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The system uses two microcontrollers:
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```
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┌──────────────┐ WiFi / MQTT ┌────────────────┐ UART 115200 ┌──────────────┐ GPIO ┌──────────────┐
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│ Home │ ◄─────────────► │ ESP32 │ ──────────────► │ Arduino Nano │ ───────► │ Brose │
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│ Assistant │ │ (controller) │ text commands │ (driver) │ │ flipdot │
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└──────────────┘ └───────┬────────┘ └──────▲───────┘ │ panels 84x19 │
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│ GPIO 13 │ └──────▲───────┘
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▼ │ power │
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┌─────────────┐ │ │
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│ Relay │ ─────────────────────────┴─────────────────────────┘
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└─────────────┘
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```
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The relay powers both the panels **and the Nano**. When the relay is off, the Nano is off
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too, and it boots again each time the relay switches on. Only the ESP32 runs all the time.
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| Part | Folder | What it does |
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|------|--------|--------------|
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| **Arduino Nano** | [src/nano](src/nano/README.md) | Drives the panel's row and column electronics directly. Keeps a frame buffer and flips only the dots that changed. Takes simple text commands over serial. |
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| **ESP32** | [src/esp32](src/esp32/README.md) | Connects to WiFi, gets the time over NTP, shows a clock with Pikachu bitmaps, exposes switches to Home Assistant over MQTT, switches display power with a relay and supports OTA updates. |
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| **BROSE9323 driver** | [lib/BROSE9323](lib/BROSE9323/README.md) | Shared `Adafruit_GFX` display driver. On the Nano it toggles GPIO pins. On the ESP32 (`-D ESPSERIAL`) it turns every drawing call into a serial command for the Nano. |
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Because the driver is an `Adafruit_GFX` subclass on both boards, the ESP32 can use the
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normal GFX API (`print`, `drawBitmap`, `fillScreen`, ...). Each call is sent to the
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Nano and drawn there.
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## Repository layout
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```
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platformio.ini one PlatformIO project, multiple environments
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lib/BROSE9323/ shared flipdot driver (used by both targets)
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src/nano/ Arduino Nano firmware
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src/esp32/ ESP32 firmware
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secrets.example.h template for WiFi / MQTT credentials
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archive/ old, unused sketches kept for reference
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CLAUDE.md project notes for Claude Code
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```
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## Building and flashing
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Install [PlatformIO](https://platformio.org/) (the VS Code extension is easiest) and open
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this folder.
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1. Copy `src/esp32/secrets.example.h` to `src/esp32/secrets.h` and fill in your WiFi and
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MQTT details. `secrets.h` is gitignored.
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2. Check the COM ports and the OTA IP in `platformio.ini`.
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3. Build or upload:
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| Environment | Board | Upload method |
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|-------------|-------|---------------|
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| `nano` | Arduino Nano (ATmega328P) | USB (`COM10`) |
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| `esp32` | ESP32 DevKit v1 | OTA over WiFi (`10.1.1.198`) |
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| `esp32_usb` | ESP32 DevKit v1 | USB (`COM11`). Use it for the first flash or for recovery. |
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```sh
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pio run # build nano + esp32
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pio run -e nano -t upload # flash the Nano
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pio run -e esp32 -t upload # flash the ESP32 over the air
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pio run -e esp32_usb -t upload # flash the ESP32 over USB
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pio device monitor -e nano # serial monitor
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```
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In VS Code you can also pick the environment in the PlatformIO status bar.
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> **Tip:** The Nano and the ESP32 share a serial line. Disconnect the ESP32 TX → Nano RX
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> wire before you flash the Nano over USB, or the upload may fail.
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## How it works
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1. **ESP32 boot.** The ESP32 connects to WiFi and starts ArduinoOTA. After a crash or
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unexpected reset it stays in an *OTA panic window* for 15 seconds, so you can flash a
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fix before the main code runs again. It then switches the display relay on, starts NTP
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and connects to MQTT.
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2. **Clock loop (every second).**
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- **07:00–22:00:** Pikachu with a thought bubble showing `HH:MM`. A yawning Pikachu is
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shown from 17:00.
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- **22:00–23:30:** the clock is only drawn on the quarter hour. In between, the relay
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turns the display off.
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- **Night:** the screen is cleared and power is cut after 30 seconds.
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3. **Home Assistant switches** (MQTT discovery):
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- `FlipDot Display Clock`: off shows a Nintendo logo instead of the clock.
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- `FlipDot Display Power`: off clears the display and cuts power through the relay.
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4. **Nano.** The Nano reads commands from the serial line and updates its frame buffer.
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On `D` it flips only the dots that changed. Every 2 minutes it redraws the whole screen
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to fix dots that did not flip.
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The serial protocol is described in [src/nano/README.md](src/nano/README.md).
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