Pseudonymous maker "Lame_Dave" has released the source code for a "Smart Girder" project, which adds an RGB LED display system to a structural girder in order to display useful information — including train times.
"It's loading data from my MQTT server," Lame_Dave explains of the eye-catching display, "which is a combination of scripts and Home Assistant. "Pleasingly it all fits exactly inside the girder running along the side of my flat. If I move, the new place will have to have a girder."
The display itself is made up of four RGB LED matrices, driven by an Adafruit Matrix Portal. Where the Matrix Portal was designed for use with CircuitPython, however, Lame_Dave took the project in a different direction: "I could not get it working reliably with CircuitPython despite spending weeks trying," he explains, "so it's all in Arduino."
The Smart Girder offers a range of informational displays, one category to each of the four panels: Train times pulled from the Transport for London (TFL) application programming interface (API); network information including bandwidth usage, number of clients connected, and data usage graphs; a Home Assistant dashboard including heating and temperature data, air quality, and car battery levels, along with details on overhead flights and a tracking system for when the car's away from home; and live weather with date and time display.
"When I started coding the [Matrix] Portals with CircuitPython the most I could get one to handle was two panels," Lame_Dave notes, "so I was planning to double up. But then I switched to Arduino code and ended up only needing one to drive everything. Using Python I'd easily use up all the memory doing simple seeming stuff with one panel."