Neopixel strip not completely lighting up

[Exothermal]

Hi all,

I've found an interesting conundrum. I plugged in a 1m/60 pixel strip into an Uno to run the standard strandtest before installing the strip in a project. I set the pin, I set the pixel count at 60, but only 45 pixels lit. So I tried FastLED DemoReel. Same story. I kicked the pixel count up to 75 just as a shot in the dark and now 54 LEDs lit. Taking it up incrementally to 79 got all 60 pixels lit. So I tried a different strip. Same story. So I tried a Mega with the same sketches. Same story. So I wired in a 24 pixel ring. It works fine.

In addition to the above issue, the strips seem to be lighting up in a more pastel hue than normal/the ring.

Soooo, did I miss something? I've run such tests many, many times. I've never seen this come up.

Thanks!

[oesterle]

Hi, Exothermal!

Can you post your code?
Can you also point to the specific strip you're using?

Cheers,

Eric

[adafruit_support_bill]

Sounds like you may have an RGBW strip and you are running code for an RGB strip. Check to see which strip you purchased. If it is an RGBW strip, you will need to specify that in your code. See the RGBWstrandtest code for an example:
https://github.com/adafruit/Adafruit_Ne ... ndtest.ino

[Ifandor]

The problem may be that Exothermal & I've been working with the small Neopixels, and forgot that the larger strips need external power. I'll check it out and get back. Thanks to oesterle & adafruit_support_bill for your thoughts! (We don't have any RGBW strips yet, so that won't be the problem.)

[kcl1s]

When about 75% of your pixels light it is usually a sign you have a RGBW strip. An easy check to see if you have RGBW is to look for the yellow section on the pixel. https://www.adafruit.com/product/2760 The RGB do not have that. https://www.adafruit.com/product/1655

Fellow hobbyist
Keith

[adafruit_support_bill]

In addition to what Keith said, the other clue is here:

In addition to the above issue, the strips seem to be lighting up in a more pastel hue than normal/the ring.

The presence of a white channel on the RGBW pixels leads to more pastel hues.