Charlieplexing 6 LEDs

ATTiny2313 charlieplexing 6 LEDs with 3 I/O Pins

Category:

Science & Technology

Tags:

• charlieplexing
• attiny2313
• avr
• atmel
• led

[frank26080115]

12

--56

34

how come 2 and 4 doesn't light up when 6 lights up?

[uidzer0tube]

Charlieplexing exploits the fact that most micro controller pins have 3 states; Input, Output, and High Impedance. The pins that would normally cause say, 2 and 4 to come on are in effect turned off by setting them to High Impedance.

[furcino]

@DusteDdekay I resolved the problem a while ago... :) I think I've put a delay inbetween the start impulses. So it would be like:

switch on led1, wait

switch on led2, wait

switch on led3, wait

I still switched between them fairly quickly and they looked as if they were lit simultaneously but this way the remaining current had time to dissipate in between the switches. So just try to put in a delay inbetween the switches ;)

[DusteDdekay]

@furcino I've experienced this same effect when using SISO shiftregisters, even at very very short pulses, where the scope confirms that there is only power for 1/4ms, and there's still a blink in the led..

[furcino]

I did this setup but I have trouble with lighting up 2 and more at the same time. Seems like there is some sort of inductance or something. I just have it on the table in front of me and switch between the first and second at 100Hz (the two leds on the very left). They light up seemingly at the same time but the one in the third column lights up too although not as bright as the other two. I don't want it to light up but don't know how to prevent it.