Hysen Labstrmnl-display
Embedded ePaper friendly Linux client for displaying TRMNL screens
TRMNL Display
A lightweight Linux command line client that renders dynamic images from the TRMNL API onto LCD/HDMI or SPI e paper displays without a desktop environment.
What it does
TRMNL Display is a lightweight Linux command line application that displays dynamic images on LCD/HDMI and SPI e paper displays such as the one in the TRMNL OG device. It fetches images from the TRMNL API or from a self hosted BYOS server and renders them directly to a video display or to e paper, providing a display experience without a traditional desktop environment. Supported formats are JPEG, PNG and BMP, and 1-bit images support an optional dark mode inversion. Refresh rates are configurable, and configuration can be done through environment variables or interactive prompts.
Installation and devices
Setup begins by cloning the repository and running the provided build.sh script, which installs dependent libraries and builds the trmnl_display binary, then presents a menu to pick the display device. The options are a framebuffer for HDMI or LCD, a Waveshare SPI e paper HAT, a Pimoroni Inky Impression Spectra 7.3, a Pimoroni Inky Impression Spectra 13.3, and a Waveshare IT8951 in 7.8 or 10.3 inch at 1872 by 1440 resolution. After selecting a device the script asks for a Device API key from the TRMNL native application, or for BYOS users a key from their own server plus a changed base_url pointing at that server.
Operation and configuration
The built program is copied to /usr/local/bin so it can be run from anywhere by typing trmnl_display. Pressing Enter skips to the next playlist item and Escape exits. For background use it can be launched with nohup, and an @reboot crontab entry with a sleep 15 delay restarts it after a device reboot so the network is ready before the first HTTP request. Configuration lives in ~/.config/trmnl as config.json, which stores the Device API Key and preferences, and show_img.json, which stores the display device settings created during build. The project is MIT licensed.
Editorial conclusion
TRMNL Display is MIT licensed and reported one hundred sixty eight stars at indexing, targeted at Linux single board computers such as Raspberry Pi and Orange Pi.
Community notes