Images on the matrix

A project log for IoT RGB LED Matrix Controller (ESP32)

This project is about building and programming an ESP32 based controller for a 32x32 RGB LED matrix, controlled from Node-RED over MQTT

solenoidSolenoid 09/08/2018 at 21:260 Comments

I wanted to display some logos on the RGB LED Matrix in view of the MacroFab Design Contest: Blink an LED. I decided to show the Hackaday Jolly Wrencher, the MacroFab logo and Mouser Electronics logo. I found all of these with a simple search, resized and edited them slightly:

The problem was that the Node-RED could only accept RGB values between 0 and 255, not a PNG file. I have yet to program a PNG parser in JavaScript, this wasn't the point of the task though.

I found this nice website that converted PNG images to XLSX files with the RGB pixel values from 0 to 255. The formatting wasn't quite right, so I applied some regex-fu and voilà: an illegible stream of numbers that, when sent to the RGB LED Matrix, would display the following logos:

Hackaday Jolly Wrencher logo on the RGB LED Matrix
MacroFab logo on the RGB LED Matrix
Mouser Electronics logo on the RGB LED Matrix

I couldn't take a video as the update rate of the LED display gave a large black scan line when using my phone camera. That's not visible to the human eye though.