ESP32 E-Paper Display Controller

A versatile ESP32-based controller for e-paper displays with web interface support. This project allows you to upload and display images on e-paper displays through a web interface.

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I’m not a C++ developer and don’t understand many concepts of this language. I’ll be happy to receive pull requests and feature requests in the Issues section.

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Features

• 🖼️ Support for e-paper displays (specifically GxEPD2_750c)
• 🌐 Web interface for image upload and control
• 📡 Wi-Fi connectivity
• 💾 SPIFFS file system for image storage
• 🎨 Support for both monochrome and color images
• 🔄 Async web server for better performance
• 📊 System monitoring endpoints
• 💩 Not all features work as intended. The code mostly works for my use cases (e.g., a pet weather station project). The code likely contains bugs, but I’ve tried to make it as readable as possible.

Hardware Requirements

• ESP32 development board
• Waveshare 7.5" three-color e-paper display
• Power supply (USB or external)

Pin Configuration

Display connections:
- BUSY -> GPIO25
- RST  -> GPIO26
- DC   -> GPIO27
- CS   -> GPIO15
- CLK  -> GPIO13
- DIN  -> GPIO14

Software Setup

1. Install PlatformIO IDE (VSCode extension)
2. Clone this repository
3. Update WiFi credentials in src/config.cpp
4. Build and upload the project:

# Using PlatformIO CLI
pio run -t upload
# Monitor serial output
pio device monitor

Web API Endpoints

• GET / - Hello world test
• GET /api/system/memory - System memory usage
• GET /api/system/list - List files in SPIFFS
• GET /api/image/draw - Trigger display refresh
• POST /api/image/upload - Upload new image
• GET /fs/* - Static file server (SPIFFS)

Usage Examples

Upload Image via cURL

# Upload an image
curl -X POST -F "[email protected]" http://esp32-ip/api/image/upload

# Trigger display refresh
curl http://esp32-ip/api/image/draw

# Check system memory
curl http://esp32-ip/api/system/memory

Image Format Requirements

• Format: BMP or raw RGB565
• Resolution: 640x384 pixels
• Color: Three-color (black, white, red/yellow)

Development

Project Structure

main/
├── src/
│   ├── main.cpp          # Main application entry
│   ├── webserver.cpp     # Web server implementation
│   ├── display.cpp       # Display controller
│   ├── image_utils.cpp   # Image processing utilities
│   ├── filesystem.cpp    # SPIFFS operations
│   └── config.cpp        # Configuration
├── include/
│   └── *.h              # Header files
└── platformio.ini        # PlatformIO configuration

Building from Source

1. Install dependencies:

lib_deps =
    ESP Async WebServer
    AsyncTCP
    ArduinoJson
    Adafruit GFX Library
    GxEPD2
    Wire

2. Configure your environment:

# Edit WiFi settings
nano src/config.cpp

3. Build and upload:

pio run -t upload

Troubleshooting

• Display not updating: Check SPI connections and reset the device.
• Upload fails: Verify WiFi connection and file size (max 3MB).
• Memory errors: Reduce image size or clear SPIFFS.

License

No license. If you see the code, feel free to use it however you want. I don’t care.