Save your project by multiplexing GPIO pins - The Byte Sized Engineer | DigiKey

I'm working on a project and I want to control a whole bunch of LEDs, but I don't have enough GPIO pins on my microcontroller. If you’ve been tinkering with electronics for any amount of time, you’ve probably run into this situation before. Maybe it wasn’t LEDs, but some other output like relays. Or maybe you were trying to read a ton of button inputs and you were short on GPIO pins. I'm going to show you how to solve this problem and potentially save your project by using a technique called multiplexing.

Bill of materials 10mm RGB LED https://www.digikey.com/short/3vj2wjvv Arduino Board https://www.digikey.com/short/70bf53w8 Breadboard https://www.digikey.com/short/nbh4q298 Resistor Kit https://www.digikey.com/short/q4w7wj75 Jumper Wire Kit https://www.digikey.com/short/8n0p92pn Keypad 12 keys https://www.digikey.com/short/f51mmwwv Keypad 16 keys https://www.digikey.com/short/zp50wmz3

7 segment LED board Github project https://github.com/bytesizedengineering/Lathe_RPM_Display

Learn More: Arduino page explaining direct port manipulation: https://docs.arduino.cc/hacking/software/PortManipulation

DigiKey blog post diving further into the topic of direct port manipulation: https://www.digikey.com/en/blog/the-case-for-direct-port-manipulation