Model Train-related Notes Blog -- these are personal notes and musings on the subject of model train control, automation, electronics, or whatever I find interesting. I also have more posts in a blog dedicated to the maintenance of the Randall Museum Model Railroad.
2025-03-26 - Matrix Display for Turnout T330
Category Arduino
Here’s a new project, Distant Signal: https://github.com/model-railroad/distant-signal
The goal of this project is to display the state of a remote model-railroad turnout on a LED Matrix Display. That’s obviously the “phase 2” of the single-LED ESP32 display I toyed with last week.
The hardware for this project is an AdaFruit MatrixPortal ESP32-S3 driving an AdaFruit 64x32 RGB LED Matrix - or more exactly some clone/equivalent of such.
Overall, the project works exactly the same as the single-LED version did:
Here’s a first potential look for the display:
This version uses a basic text-based configuration script to define the content of the screen:
That’s the configuration script that the Conductor automation program would send to the display to initialize it. The configuration script defines several “states”, for example “T330 normal” vs “T330 reverse”. Each state is describes the entire content of a screen using a set of graphic primitives -- line, rect, text, and polygon.
Then MQTT would be used to select which state to display -- in this case turnout states, as the automation dictates which state should be displayed based on turnout sensor feedback. From the ESP32 point of view, the behavior is totally agnostic -- all it does is display a full screen of “something”.