Picture of Charlieplexing with the Raspberry Pi
I've always been interested in Charlieplexing, but never had any means to get into it.  When I got my Raspberry Pi, I figured it would make a great platform to learn how to Charlieplex.

There are already a ton of Instructables on Charlieplexing out there, so I won't go into the theory behind it, or how it works.  This Instructable will instead focus on how I wired it up on my breadboard using 3 pairs of LEDs and 3 leads, then expanding it to 10 pairs of LEDs with 5 leads.

From a learning perspective, my objective was to learn about Charlieplexing.  How does it work, and how do you code it.

Step 1: A Pair of LEDs

Picture of A Pair of LEDs
Charlieplexing is all about wiring up LEDs in pairs between sets of two leads.  Each LED in the pair lights in a "different direction," if you will.  This lets you run current from lead 1 to lead 2, and light one LED, then run current from lead 2 to lead 1 and light the other LED.

Wiring was going to be a mess, I figured, so I wanted my pairs of LEDs to be pretty compact.  I put the LEDs in my breadboard facing opposite directions, in the same columns, practically touching, with a resister wired right next to them.
FF971 month ago
Can I use resistors only on the RPi leads?
mrmath (author)  FF971 month ago

I'm not sure what you're asking, honestly. How else would you use them?

FF97 mrmath1 month ago

Nevermind, it's working, thank you for the post

thanks for posting, I'll probably use this to get started working with raspberry pi.
mrmath (author)  amandaghassaei3 years ago
You're welcome. But, based on some of your 'ibles, doesn't look like you need my help much. :)