Having some more problems with WS2811s.

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1

Having some more problems with WS2811s. Lots of flickering and I’ve tried every idea I can think of.

I’m controlling a strip of 60 (1m) with a 5V Arduino pro mini. The pro mini is powered by a 4xAA battery pack (at 5.8v) and the strip is on a 5V 200W supply. All share common GND. Also both ends of the strip’s 5V+GND are connected to the supply and data out is on GND. I put a 220 ohm resistor on the data line for good measure. With an all red test pattern, I get tons of flickering at the back of the strip. Lighting just the first 30 pixels works fine. Any ideas?

#include "FastSPI_LED2.h"
#define NUM_LEDS 60
#define DATA_PIN 2
CRGB leds[NUM_LEDS];

void setup() {
  delay(2000);
  FastLED.addLeds(leds, NUM_LEDS);
}
void loop() {
  for(int i = 0; i < NUM_LEDS; i++) {
      leds[i] = 0xFF0000;
  }
  FastLED.show();
  delay(100);
}
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Try setting the brightness to 128 or even 64 and see if that changes anything - if so you may be having a power drop problem. B

The pro minis are 5v/16Mhz, right?

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Indeed, I can remove the flickering at 64 (but not 128) when all are set to red. On all white, even at 16 I still see some though. If I reduce the updates to every couple of seconds, the strips change color on the updates with no flicker in between.

If I light up on the last 10 pixels on full white, no problem, but 20 is too many!

I tried a different strip and it behaved a little better but not by much. Maybe these are bad strips?

Yep, its 5v/16Mhz

4

That really speaks of a power problem (the fact that changing brightness changes how much flickering you’re getting). Is your power supply a PC power supply by any chance? If so - not all the 5V rails on that are created equal - some are only 0.5-2A outputs.

5

I’ve used the power supply successfully for a while actually. It’s one of these: http://www.aliexpress.com/store/product/200W-Dual-Output-Switching-Power-Supply-88-264VAC-input-12V-200W-output-CE-and-ROHS-approved/701799_289599911.html

I just tried a Teensy 3.0 and it works fine with all 60 on full white! Shame because I bought a bunch of these pro minis in an attempt to save $10…

6

Huh - were these ali-express sourced pro-minis? Or where did they come from? We had weird signal problems with nanos recently, that went away when swapping with anything that wasn’t a nano, really.

7

Got them from Sparkfun. (To be fair I’ve only tried one so far.)

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Weird - until I started using the teensy 3’s the pro minis from spark fun were my go to board.

9

Ok, just tried another pro mini with the same results. Have you used them much with WS2811s? WS2811s are pretty uptight creatures it seems.

Overall thanks for helping me convince myself I’m not crazy. :slight_smile:

10

Had also some flickering on a w2801 strip. Played with the timing and got it working

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Michel that is likely a different issue. The wa2801 requires a certain amount of pause between writing to the strip. The data sheets that I have always put this at 24us, but apparently at least one manufacturer out there requires 500us. I will be updating the library to be more conservative in enforcing this v

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@Greg_Friedland just a thought - check that the Pro Mini boards don’t use 20MHz crystals instead of 16MHz (by accident). I saw this exact problem when switching to 20MHz on the ATmega328, but thankfully the new version of FastSPI was able to handle it once I got everything else right (boot loader & Arduino boards.txt)

13

Yeah, the new version of the library uses the F_CPU value, which is the clock frequency, to adjust timings for the Timing specific chipsets like the ws2811

14

Interesting idea. I ended up ordering a bunch of teensy’s overnight mail to get them in time for bman. Won’t have a chance to test out this before but will try it afterwards.