Datasheet

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This updates the whole strip at once, and despite the extra step is actually a good thing. If every call

to setPixelColor() had an immediate effect, animation would appear jumpy rather than buttery

smooth.

You can query the color of a previously-set pixel using getPixelColor():

This returns a 32-bit merged color value.

The number of pixels in a previously-declared strip can be queried using numPixels():

The overall brightness of all the LEDs can be adjusted using setBrightness(). This takes a single

argument, a number in the range 0 (off) to 255 (max brightness). For example, to set a strip to 1/4

brightness:

Just like setPixel(), this does not have an immediate effect. You need to follow this with a call to

show().

setBrightness() was intended to be called once, in setup(), to limit the current/brightness of the

LEDs throughout the life of the sketch. It is not intended as an animation effect itself! The operation

of this function is “lossy” — it modifies the current pixel data in RAM, not in the show() call — in

order to meet NeoPixels’ strict timing requirements. Certain animation effects are better served by

leaving the brightness setting alone, modulating pixel brightness in your own sketch logic and

redrawing the full strip with setPixel().

I’m calling setPixel() but nothing’s happening!

There are two main culprits for this:

1. forgetting to call strip.begin() in setup().

2. forgetting to call strip.show() after setting pixel colors.

Another (less common) possibility is running out of RAM — see the last section below. If the

program sort of works but has unpredictable results, consider that.

Can I have multiple NeoPixel objects on different pins?

Certainly! Each requires its own declaration with a unique name:

uint32_t color = strip.getPixelColor(11);

uint16_t n = strip.numPixels();

strip.setBrightness(64);