In our last post, we detailed how soil moisture sensors and datalogging are not exactly the cure for dead plants (or neglectful students). The next step at SLA Beeber was to give students blindingly bright visual cues as to when their plants required watering. Along with taking soil moisture readings and determining a wet or dry state, students programmed their own designs onto an Arduino-powered LED matrix. Remember Lite-Brite? It’s kind of like that, except it’s coded in Arduino using an x-y coordinate system, geometric shape commands and color codes. Students began by sketching their designs onto a 16×32 grid, then breaking the grid into rectangles, lines, and pixels as lines of code:
Adafruit has an excellent tutorial on how to wire this to the Arduino and program it. We put the display inside a Pelican case to keep it dry and set it up in the school’s hallway, where one can only hope the plants’ occasional pleas for water will catch someone’s eye.