I am having issues regarding addressing my WS2812B LED strip.
I have followed the guide video and article:
I am currently using a Raspberry Pi 3 A+. When I am running the code from the article “strandtest.py” and “OneStripNeopixel.py” there seems to be no obvious pattern or color. You can see the video I have linked below (running “strandtest.py”). There is clearly something wrong: When I first run “strandtest.py” not much is happening, but if I change the DMA channel from 10 to 1, run it, and then change it back to 10, the patterns make more sense, but the colors are still random. Also, when I change the number of LED pixels in “strandtest.py” there is still some issues, e.g: setting LED_COUNT to 20 and the first 37 LED will light up (still in random colors and patterns).
What I have tried:
I have tried to control the LED strip with a NodeMCU amica and WLED. This works with no problems. Since the NodeMCU also uses 3.3V data logic, I don’t think that is the issue. t
A little update:
I have tried running the setup with an old Pi 1, with no improvement.
Moreover, I also tried my Pi 3 A+ setup on another strip my brother had lying around, which had the exact same behavior also.
From the first video, it looks like there might be a grounding issue.
Do you have a multimeter to test the continuity(and resistance) from your Raspberry Pi to the Din pin of the strip?
What were the settings and ratings of your power supply? If the current limit is set too low you might see some strange behaviour.
The LED strips might be in a different colour configuration, most WS2812 strips are GRB but if the order changes or white is included odd sequences can occur!
I have tried to measure the voltage from the external LED power supply. It very stable and lies between 5.0 to 5.03. I am not quite shure what else to measure and how? (referring to “continuity(and resistance)”). The external power supply is set to 5V and can go up to 5 amps, but the highest I have seen is 2.63 amps. I have tried to change the pixel order from RGB to GRB (also with W). I don’t see any change.
Everything is now working as it should (sort of)!.
I have a RPi 4 model b running octoprint. I took this pi and the SD-card from my RPi 3 a+ and used the same setup as in the pictures. This works with no problem and runs “strandtest.py” exactly as in the video guide.
So why is this? I would love to run my LED’s on the RPi 3a+ , so where do I go from here?