M5Paper TRMNL Firmware

Arduino firmware for using the M5Paper e-ink device as a TRMNL display.

Features

• Full M5Unified library support (M5EPD deprecated)
• PNG and BMP image support
• Deep sleep power management with RTC persistence
• Battery voltage monitoring
• Automatic WiFi retry logic
• Wake on button press or timer

Hardware Requirements

• M5Paper e-ink display (960x540)
• WiFi network access

Installation

PlatformIO

1. Clone this repository
2. Update WiFi credentials in m5paper_trmnl.ino
3. Set your TRMNL API key
4. Upload to M5Paper

Arduino IDE

• Install M5Unified library
• Install ArduinoJson library
• Configure ESP32 board settings

Configuration

Edit these values in the code:

• TRMNL_API_KEY - Your TRMNL API key from trmnl.app
• WIFI_SSID - Your WiFi network name
• WIFI_PASS - Your WiFi password

Usage

The device will:

1. Wake up (timer or button press)
2. Connect to WiFi
3. Fetch display from TRMNL API
4. Render image to e-ink screen
5. Enter deep sleep until next refresh

Troubleshooting

• WiFi won't connect: Check credentials, device will auto-retry 3x
• Image won't load: Verify TRMNL API key and network connectivity
• Battery drain: Normal refresh rate is 15 minutes (900s)

Credits

Built for the TRMNL BYOD program

License

MIT