Hey guys!
I just started using FastLED today, and I’ve run into something strange.
I have 8x 5m neopixel LED strips with 30 LEDs pr meter installed in my roof. They are run by a Teensy 3.2 with an OctoWS2811 adapter. Until today I’ve been using the OctoWS2811 library, and it’s been working nice.
So, I uploaded the OctoWS2811 example sketch, from the FastLED library, to my Teensy and fired it up. I was quite pleased to have a nice rainbow all over my roof. Then I noticed that the first LED in the rainbow of each strip was flickering. Setting brightness to 255 didn’t change it, ‘FastLED.setDither( 0 );’ didn’t change it and setting saturation to max made it almost go away, but not completely.
Then, by pure chance, I noticed in my Arduino IDE under ‘Tools->CPU speed’ that ‘96MHz optimized (overclock)’ was selected.
I tried switching to ‘72MHz optimized’ and the flickering vanished completely!
I’ve always used ‘96MHz optimized (overclock)’ since the very first time I started using Teensy and OctoWS2811, and never experienced flickering before.
Is there something I can change in order to keep using ‘96MHz optimized (overclock)’?
I have no experience in the low level programming of microcontrollers, so I’m not going to be able to dive into the library and look for clues in the code myself.
I’ll look into that - I’m usually running at 96mhz or above, and haven’t been getting this issue, but I’ve also been doing a lot of juggling.
Out of curiosity are you using FastLED’s parallel output (eg WS2811_PORTC) or the octows2811 FastLED driver? (If you post your code to gist I can take a look at what you’re doing and try recreating a setup for testing)
I just read this and it solved my problem. I have just ported a Burning Man project from a Mega to a Teensy 3.2 with an Octo ws2811 adapter. It has 933 neopixels in 8 strips of varying length. I set it up as recommended for the wiring and following the octo example in Fastled. With a little help on proper programming in C++ (thanks, Daniel Garcia) I got everything running, but with one peculiarity. There are two functions that involve setting a strip to black, and then lighting a portion in various ways. In those two functions some of the pixels that should have been off flickered.It only happens on three of the eight strips and the flicker rate on one (the 2 pin) is twice as fast as the others.
I just set the speed on the Teensy to 72 mhz and the flickering is gone.
I’m happy my post could solve your problem 
Tell me if you find a way to overclock the Teensy without causing flickering!
No one ever answered whether they were using fastled’s parallel output or the octows2811 driver. (FTR - I usually run my parallel output code at somelike like 144Mhz
I’m using the octo ws2811 driver, but for my purposes running at 72 mhz works fine.
I somehow totally forgot that you asked Daniel.
I’m also using the octows2811 driver, so I guess thats a possible reason for the flickering.
FastLED.addLeds(leds, NUM_LEDS_PER_STRIP);