2 sets of Charlieplex strands (6 LEDs each) ran off the same 3 pins?

Projects General Guidance
1

Hey all,

I'd like to know if I can safely and successfully run 2 sets of charlieplexing strands (6 LEDs each), from the same 3 arduino pins? Seeing that each arduino pin supplies 40mA, and the LEDs take 20mA, theoretically could I have 2 separate sets of charlieplexing light strands attached into the same pinout, correct? Each circuit would then use up the 40mA and stay within the pins limit. I know I wouldn't be able to completely control all 12 LED lights individually, rather I can control the 6, and have a duplicate copycat set doing the same thing (which is fine for the project).

I created the first set of charlieplexing lights and I successfully made it work for controlling the 6 lights from the 3 pins, but if I were to duplicate it, and attach it to the same pins rather than another 3 pins, would it work, or would it fry the arduino, or burn out the lights?

Any advice/experience would be helpful.

2

Rufio:
Seeing that each arduino pin supplies 40mA,

Wrong! :astonished:

3

Rufio:
Seeing that each arduino pin supplies 40mA, and the LEDs take 20mA

40 mA is absolute maximum rating. Not a good idea to operate a pin at that current.
20 mA is the normal rating.
Furthermore, 20 mA is a lot for an LED. Many are pretty bright at 5 mA or even less. Consider increasing the value of your current limiting resistors and you can add a few more LEDs.