LED matrices are a great way to add color to a project’s output, but what if you want to use it as an input device as well. While that idea might seem far fetched, this project by tuenhidiy shows how to do so using 16 IR emitter/receiver pairs. The unit is controlled by swiping the screen left or right, changing the color of each column from red to green, or vice versa. Notably, the screen setup is also capable of displaying text and other images, which could come in handy for other projects.
The device is powered by an Arduino Mega, which presents a fairly robust number of IO pins. However, in order to take in the 16 inputs from each IR pair, plus control the 16×32 pixel bi-color matrix constructed out of eight smaller 8×8 matrices, the project makes heavy use of multiplexers/demultipleers to handle everything.
While the matrix couldn’t exactly be classified as simple, if you did want to expand upon it further, one could see a similar project expanded into a second dimension with another array of LEDs on the vertical edge. The same concept could even be applied to larger off-the-shelf matrices, which would simplify the project significantly.
Code can be found on GitHub, and you can see it being calibrated and used in the video below.