Moving Rainbow Programmer's Guide

This guide assumes you are somewhat familiar with Arduino programming and using the setup() and loop() functions. It assuems you have hooked up your LED strip to your Arduino and are ready to learn how to program the LED strip.

This programming guide will cover:

How to use the setup and loop functions
How to set the color of a pixel
How to use a for loop to change all the colors in the strip
How to use the delay function slow down your patterns
How to create and use functions
How to use various such as the if/then/else statements to conditionally turn on pixels

Getting Started

Setup and Loop

In these labs our Arduino programs will have four parts.

A, preamble section that will declare various things
A setup function, setup()
A looping function called loop() that will run until the devices is reset or turned off and loop.
A list of functions that are called by the setup and loop functions

Sample Preamble

#include <Adafruit_NeoPixel.h>
#define LEDPIN 12 // connect the Data from the strip to this pin on the Arduino
#define NUMBER_PIEXELS 12 // the number of pixels in your LED strip
Adafruit_NeoPixel strip = Adafruit_NeoPixel(NUMBER_PIEXELS, LEDPIN, NEO_GRB + NEO_KHZ800);

Setup

This function will run only once. It is used to setup the initial memory variables we need in our programs

void setup() {
  strip.begin(); // Initialize all the variables
  strip.show(); // Initialize all pixels in the strip to be off
}

Loop

The loop program will run over and over. Here is a sample program that will blink the first pixel in the strip:

void loop() {
  strip.setPixelColor(0, 255, 0, 0); // set pixel 0 to be red
  strip.show(); // send red to strip
  delay(1000); // wait a second
  strip.setPixelColor(0, 0, 0, 0); // set pixel 0 to be red
  strip.show(); // send off to strip
  delay(1000); // wait a second
};

Basic Functions

Initialize strip

Adafruit_NeoPixel strip = Adafruit_NeoPixel(NUMBER_PIEXELS, LEDPIN, NEO_GRB + NEO_KHZ800);

Send data to the strip

strip.show();

Set a pixel color

The most important function in our programs is the function to set one of the pixels to a specific color. We use the following function:

strip.setPixelColor(index, red, green, blue);

Where the "index" is the number of pixel to set, starting at pixel 0. The second pixel is called "1" etc. Each of the index numbers is off by one.

strip.numPixels()

Returns the number of pixels in the LED strip.

The first pixel has an address of "0", the second an address called "1" etc.

Wait

delay(milliseconds)

You can also lower the overall brightness of the strip using the strip.setBrightness() function.
It is designed to be used only in the "setup()" function and it takes a number from 0 to 255 with 0 for off and 255 for maximum brightness.

If you want to turn your LED strip to 1/4 brightness you can add the following:

strip.setBrightness(64);

Programming Guide