I have 150 WS2811 leds being controlled by a Particle Photon and powered by 5v 20amps. Everything works fine, until I put the brightness above about 150, at which point the first LED starts flickering while all the other LEDs behave as they should. Then, if I ramp the brightness up even more, the first LED flickers more, and the LEDs beyond that first LED flicker with it too. I got a level converter today which I thought was the problem but it doesn’t appear to make any difference. I’ve also tried using one spare LED as a ‘bridge’ with a diode on the 5v in to lower the voltage to better match the 3.3v (saw this suggested elsewhere), but again, it doesn’t make a difference.
Set the LEDs to just show white in color. No effects. Just on. Increase the brightness slowly. Look at the far end of the chain. Is it the same color white as the end near the power supply?
Hi Stuart,
I’ve just set them to white. No, they brown out. At 80 brightness they’re all white, at 100 they start to brown out about 3/4 of the way through the strands, and at 130 brightness the end 1/4 are almost all orange, and I’m getting flickering. At 150 brightness, more orange and a load of flickering.
I’ve tried injecting power between the strands (each has 50) which does seem to help a bit, but there’s still a lot of browning out and flickering. I’ve had the power supply I’m using running 250 WS2801 LEDs before so I didn’t think it was that… but I then again I was injecting power from it every 25 LEDs then. Maybe powering 150 on full brightness with 3 power injections isn’t a reasonable expectation?.. or could there be something else going on?
The rule of thumb is 60mA per led-package. Ergo you have 150 ×.06A = 9A which should leave plenty of head room on your power supply. But the point of the white test, is to show you, visually, the effect of volt drop along the string. Run the test again, and measure the volt drop along the string with a DMM. Those puny tracks cant deliver the current you need along the length of the strip. Power injection will help. I use mains cable, with a conducter cross section of 1mm (sorry i dont know AWG). I can run 100 leds before injection.
I have a video in the making of some measurements i’ve taken using a good bench DMM of the effects of long strings. Even a string showing all black (all leds off) places load on the supply.
Hi again, I know where my problems were stemming from now! I now have no flicker and I’m not using a level converter either! Yes! Before, I was powering the photon and LEDs on separate lines from a single power source. The line to the LEDs had a capacitor on it for smoothing and the photon’s line didn’t. I am now taking the power for the photon after it goes through the capacitor and now everything works!
Just in case anyone finds this post and has this same problem, I’ve just set up some more WS2811 LEDs and was having similar ssues. This time though it seemed that the problem was the the connection between the power supply and the board/LEDs which I was using standard crocodile clip wires for. Once I took these out of the equation and replaced them with a more permanent solution the flickering stopped.
