Multi-topic MQTT gauge display with web configuration portal and OTA updates.

• ESP32 development board
• ST7789 TFT Display (240x280 pixels)
• SPI connections as defined in platformio.ini

TFT_MISO  = 19
TFT_MOSI  = 23
TFT_SCLK  = 18
TFT_CS    = 15
TFT_DC    = 2
TFT_RST   = 4
TFT_BL    = 21 (backlight)

1. Flash firmware to ESP32
2. Connect to WiFi: Device creates AP G86-Display-AP (password: golf1986)
3. Configure WiFi: Captive portal opens automatically
4. Set MQTT server: Enter broker address and port
5. Access web interface: Navigate to device IP address

• Real-time value display
• WiFi/MQTT connection status
• IP address information
• Quick access to configuration and OTA

• MQTT Settings: Server, port, username, password, client name
• Topics: Add/remove/edit subscriptions with gauge settings
• Display Settings: Brightness (0-255), refresh rate (16-1000ms)

• Drag-and-drop firmware upload
• Built-in with AsyncElegantOTA

Returns current system status:

{
  "wifi": true,
  "mqtt": true,
  "ip": "192.168.1.100",
  "uptime": 3600,
  "activeTopic": {
    "displayName": "Engine RPM",
    "value": 4500.0,
    "units": " RPM",
    "lastUpdate": 123456789
  }
}

Returns full configuration (JSON export)

Import configuration (JSON body)

List all configured topics

Add new topic:

{
  "topic": "/GOLF86/ECU/RPM",
  "displayName": "Engine RPM",
  "gauge": {
    "minValue": 0,
    "maxValue": 7500,
    "units": " RPM",
    "colorScheme": 4
  }
}

Remove topic by index

Set active topic

Restart device

• 0: RED2RED (solid red)
• 1: GREEN2GREEN (solid green)
• 2: BLUE2BLUE (solid blue)
• 3: BLUE2RED (full spectrum)
• 4: GREEN2RED (high temperature style) ⭐ Default
• 5: RED2GREEN (low battery style)

On first boot, system creates default configuration:

MQTT Server: localhost:1883
Username: public
Password: public
Default Topic: /GOLF86/ECU/RPM
  - Display Name: Engine RPM
  - Range: 0 - 7500
  - Units: RPM
  - Color: GREEN2RED

pio run -t upload
pio device monitor

1. Open project in VS Code
2. Click "Upload" in PlatformIO toolbar
3. Open Serial Monitor for debug output

Network Task (Core 0)

• WiFi management and reconnection
• MQTT connection and message handling
• Web server operation
• State machine updates
• Auto-topic switching

Display Task (Core 1)

• High-speed TFT rendering (30-60 FPS)
• Partial gauge updates
• Connection status display
• Frame pacing

Published under MIT licence. Copyright © 2025 Arvis Skrējāns