Scanning at 80 frames per second he gets a nice, flickerless display. To make both the LED matrix circuit board and the control board, [Joekutz] carved out isolation paths in copper clad boards ...
Put together on a piece of perfboard, the handwired circuit also includes an Adafruit PowerBoost 500 Charger, a 3.7 V 2500 mAh LiPo battery, a IS31FL3731 Charlieplexed PWM LED driver, and a piezo ...