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Dimming White channel on RGBW Neopixel
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Dimming White channel on RGBW Neopixel

by nl28382 on Sun Nov 15, 2020 10:26 pm

I am using a RGBW neopixel strip with a Rasp P and the CircuitPython library.. I set a series of LED's with lower and lower white values to dim each successive LED, However, from a white setting of 256 down to 40 there is little visible difference. There is more of a difference if I set the overall brightness to 0.8 or higher but I want to keep the strip fairly dim. How do I get a graduated brightness on the white LED's?

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Re: Dimming White channel on RGBW Neopixel

by adafruit_support_bill on Mon Nov 16, 2020 7:06 am

There are a couple of factors at play here:

The first is that the perceived brightness of LEDs is not linear with respect to the PWM duty cycle. You can compensate for that with Gamma Correction. But you do lose some resolution over brightness control: https://learn.adafruit.com/led-tricks-g ... /the-issue

The second issue is the overall brightness setting. When you set the overall brightness to a lower value, you further lower the available resolution.

To maintain resolution on the white channel, it is best to keep the overall brightness at 100% and adjust your RGBW values individually.

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