The LilyGo T5 4.7 is an e-ink display combined with an esp32 chip, which allows the display to be updated with data fetched over wifi/bluetooth. The examples from LilyGo's getting started repository cover the basics in terms of installation and displaying local data: text via built-in functions (with an extra font header) or an image converted to a .h file via their imgconvert tool.
I created this repository to serve images over the network to the LilyGo to be able to draw images on a server/desktop before sending them over to the device. Two main reasons for this approach:
- Flexibility of displaying data, no need to re-flash the ESP32 chip
- Complex drawings are easier to generate on the desktop than on the LilyGo/ESP32
For hardware you'll need the LilyGo T5 4.7 of course. I got mine from AliExpress.
For the software you'll need:
- Arduino IDE (https://www.arduino.cc/en/software). For setup instructions see the official repository: https://github.com/Xinyuan-LilyGO/LilyGo-EPD47
- Python (with pip package manager)
- You'll need to install the following python libraries afterwards:
pip install numpy opencv-python flask
You'll find two folders in this repository:
├───lilygo - Contains the ESP32 code which needs to be flashed on the device
└───server - Contains the code to run on the server
The E-Ink display has the following characteristics:
- pixel data should be in a
uint8_t*buffer - each pixel is 4 bits long (so two pixels per byte)
- 4 bits -> 16 grayscale tones supported
- Byte order is BIG endian -> most significant byte first
- 0x0 -> Black
- 0xF -> White
The webserver (server/imageserver.py) converts any given image to the format explained previously using a combination of numpy, opencv. It also uses the flask library as a webserver.
You're free to re-use this code however you want (commercially or otherwise), attribution would be nice, but is not required by any means.