Project 13: LED Matrix

Description Discover how to connect an LED Matrix to the Raspberry Pi. The LED Matrix is a grid of 8 by 8 red LEDs that can be individually lit at different intensities, and forms the basis of a simple display. The LED Matrix can be used for games, a clock, text displays, histogram displays and many other uses.
Materials RaspberrySTEM™ Base with Raspberry Pi
RaspberrySTEM™ CREATOR Lid
LED Matrix RaspberrySTEM™ Cell


Prerequisites Error: Reference source not found
Error: Reference source not found

What is the LED Matrix RaspberrySTEM™ Cell?
It consists of:
  • A LED Matrix driver PCB – a circuit board, that receives data from the Raspberry Pi, and displays it on an LED Matrix using a small low-power micro-controller (Atmel ATTiny48
  • An LED Matrix – a grid of LEDs, where for each row the anode (positive-side) of the LEDs are connected together. LED matrices can only show one unique row of LEDs lit at one time, therefore the micro-controller is required to sequence through each row one at a time. This occurs faster than the eye can perceive (through the eye's persistence of vision), and therefore appears to be a solid image.
  • Communication from the Raspberry Pi to the LED Matrix RaspberrySTEM™ Cell occurs over the SPI bus
  • The SPI (Serial Peripheral Interface) is a common interface for sending data between processors and other ICs.
  • The micro-controller stores the brightness level of each LED, on a scale from 0-15. In order to update the full LED Matrix display, the Raspberry Pi must send 64 (i.e., 8 x 8) brightness levels, one for each LED, to the LED Matrix RaspberrySTEM™ Cell.

Connect the LED Matrix