DotStar strips aren't lighting up expectedly

Hardware
1

I have a DotStrip from Adafruit on which I run a ‘comet animation’ of different colors. I ordered 5 more of the same Dotstrips to add on to my other strip. However, these new 5 strips give off a much different coloring than my original one. Why???

I try displaying white coloring by setting R=200, G=200, B=200. It shows up a nice white on my original DotStrip. However, on the new ones, it’s a very blue color. And when I do pink on the original strip, it shows up as a light blue on the new strips. Why the change? The entire setup should be the same.

But the pure blue, red and green colors show up the same. It seems I just can’t achieve the same whiteness in these strips. Is it possible for the strips to have changed?

2

If it’s the exact same setup, this might be something to contact Adafruit about.

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3

Are you testing the new strips as first in the row or as extension to the existing?
If the latter, then I’d suppose a supply power issue.

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4

Testing as first in the row, not an extension. Definitely not a power supply issue. I’ve replaced the original strip with the new strip. With exact same setup, the colors are very different. I can’t achieve anything close to white in the new strip, nor can I achieve anything other than blues reds or greens. No matter how I change the RGBs, I can’t get orange, pinks, purples, etc anymore.

5

As seen in the example from the library:

//-------------------------------------------------------------------
// NOTE: If you find that the colors you choose are not correct,
// there is an optional 2nd argument (for HW SPI) and
// 4th arg. (for SW SPI) that you may specify to correct the colors.
//-------------------------------------------------------------------
// e.g. Adafruit_DotStar(NUMPIXELS, DOTSTAR_RGB);
// e.g. Adafruit_DotStar(NUMPIXELS, DATAPIN, CLOCKPIN, DOTSTAR_RGB);
//
// DOTSTAR_RGB
// DOTSTAR_RBG
// DOTSTAR_GRB
// DOTSTAR_GBR (default)
// DOTSTAR_BRG
// DOTSTAR_BGR

Could you give those a shot to see if it makes any difference?

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6

Thanks. I’m not using the library but I did try checking on the RGB order but doesn’t fix the issue. When I do RGB(200,200,200), it still shows up very blue on the new strip rather than the whiteish color on the first strip I got. Even changing the blue to be less doesn’t do much. Very difficult to get any variation in colors in these new strips.

7

Just fyi...this is the response I received from Adafruit. Seems like color variations in strips are normal and best solution is for it be dealt with via software:

We don't have any control over the frequency matching of the strips we get from the manufacturers, and we can't afford to spend the time testing for a particular match.

It takes less time, money, and effort to compensate for the mismatches in software. You can create 'gamma' data structures for each strip that have multiplers for the red, green, and blue pixels, keep track of which pixel number is on which strip, and apply the appropriate gamma correction to the color when you update the colors.

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