Colours on a Pixel Ring

Part of the Displays and Sensors section of Coddy's Arduino journey. Lesson 13 of 24.

This ring holds 16 NeoPixels on one data wire. The first pixel passes the rest of the data on to the next, so one show() sets them all. They are numbered 0 to 15.

ring.Color(red, green, blue) packs a colour into one number, so you can keep it in a variable and use it again. Its type is uint32_t: a whole number of 32 bits that is never negative, big enough for all three parts.

uint32_t purple = ring.Color(150, 0, 255);

ring.setPixelColor(3, purple);
ring.setPixelColor(7, purple);
ring.show();

A pixel you never give a colour stays off. 255 for all three parts is white.

Challenge

Easy

The ring is on pin 6. Light four pixels, a quarter of the ring apart:

pixel 0 red, pixel 4 green, pixel 8 blue, pixel 12 white
make each colour with ring.Color(), every part 0 or 255
leave the other pixels off

Press Run, then Check.

Try it yourself

#include <Adafruit_NeoPixel.h>

// 16 pixels, data on pin 6
Adafruit_NeoPixel ring(16, 6, NEO_GRB + NEO_KHZ800);

void setup() {
  ring.begin();

  // pixel 0 red, 4 green, 8 blue, 12 white

  ring.show();
}

void loop() {
}

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Displays and Sensors

Practice on your own: Arduino playground