ws2811 wont work at all

Hi everyone,

i have some ws2811 strips and I cannot seem to get them to output anything. I believe i have it all wired correctly, coming out of a single brick is a 12v and 5 line with a switch halfway up the cord connecting the grounds, which powers the mega with 5v and ws2811 with 12v. Theres a 220ohm resistor between the arduino and the data line on the WS2811.

I’m using FastLED’s blink example to try to get something out of it and work on it from there, but nothings working. Any advice would be great, i feel like something must be broken but i might just be overlooking something super obvious.

Blinknotworking.txt (3.65 KB)

I think I can guess the problem. You are powering the mega with 5V to its barrel socket. This socket feeds the on-board voltage regulator which needs at least 6.5V to run. Right now, the mega is running (miraculously) on around 3.5V, and it's digital pin is outputting a data signal which is also about 3.5V, which won't be enough for the strip to receive the data.

You have a couple of options.

  1. Connect 12V to the mega barrel socket. This will enable the mega to run at 5V and output a 5V data signal. This a be ok with your current circuit, but take care of adding other components which would draw significant current at 5V, as this could lead to the regulator overheating.

  2. If you are sure that the 5V supply from the PSU is properly regulated, use it to power the mega through the 5V and ground pins, not the barrel socket.

On the other hand, you have USB connected, which should be providing the mega with 5V. So also try disconnecting the 5V from the Mega's barrel socket and connect a common ground from the mega to the breadboard.

SOLVED thank you so much i was about ready to give up. I hope someone finds this before they pull out their hair. (side note the 100uf cap was to little and as soon as i put 12v through the arduino it promptly popped which gave me my first indication you were right.)

Congratulations on getting it working. Unfortunately your description of how you got it working will be too brief to help others, I suspect. Which of my 2 suggestions did you follow, for example?

side note the 100uf cap was to little and as soon as i put 12v through the arduino it promptly popped which gave me my first indication you were right.

No the capacitor was not too little, it popped because the voltage rating was exceeded. Even a large value capacitor would have popped or even burst into flames if its voltage rating was less than 12V.