THE CODE

Published October 28, 2019 © CC BY

NeoPixel Tutorial

RGB addressable strip.

BeginnerProtip1 hour76,845

Things used in this project

Hardware components

Arduino UNO

Jumper wires (generic)

Adafruit NeoPixel Digital RGB LED Strip 144 LED, 1m White

Software apps and online services

Arduino IDE

Story

In this tutorial, we will learn how to control individually addressable RGB LEDs or a WS2812B LED strip using Arduino.

For this tutorial, we'll assume that you're working with LED strips – the simplest way to light up your bike, bar, CPU tower, and so forth.

You can cut the strips to any length you like; to do so, make sure you cut across the center of the oblong copper pads. That leaves you with solderable pads on each end, which will allow you to chain them together after the fact.

Solder some male-male headers to the end, with the little arrows on the LED strip pointing away. The arrows should point away from your headers. Put your headers behind the arrows. (It helps to chant this in your head, if you're doing lots of them...)

Note: Depending on where you buy your "NeoPixels", you may end up with something that has the pins in a different arrangement. Pay attention to the labels, as well as the schematic :)

THE CODE

Go download Adafruit's NeoPixel library to get started. You can just download the.zip file with the library, unzip it on your computer, and drag the contents into your Arduino libraries folder. (The "libraries" folder is usually created in the same "Arduino" folder where you save your sketches. If you don't have one yet, go ahead and create it.) Also, restart the Arduino IDE if you already had it open.

Once it's up again, you'll have some new example sketches. Let's take a look!

File > Examples > Adafruit NeoPixel > simple

This guy will light up your LEDs green, one at a time. How does it work? We're gonna use another for loop!

As we saw before, for loops are useful for nudging a number higher. We can use that to modify each LED in a sequence – or every other LED, or whatever you like.

So, first, we tell the sketch to include Adafruit's library.
Then, we define two variables: the data pin we're using (any PWM pin), and the number of pixels in the strip.
In the next bit, we initialize the strip as a new object, pixels. (You can call it whatever you want, of course.)
Then, we set a delay value, which will be used later to pause after lighting up each LED.

There's a little bit of board-specific code in the setup code, and then we tell the NeoPixel library to start communicating with this strip.

Loop time!

We've got another for loop, which is kicked off when the variable i is equal to 0.

Note that this is actually where we're defining the variable, as well – so it starts as 0. You can tell because of the int marker, and also because there's only a single = sign. (One = sets the first thing equivalent to the second, as in i = 0; two == checks to see whether the two sides are equivalent.)

So, this for loop says:

If i is 0 when you hit this block of code (and it is), then as long as i is less than the declared number of pixels, bump it up by 1...
then, set the color of the first pixel in the pixels strand to green...
then, actually push that color to the pixel...
then, wait 500ms (from the delayval setting)...
and repeat for each successive pixel, until you max out the strand.

It's a simple but fun animation. :)

Hit upload and deploy this code to your strand.

Code

Arduino Neopixel

// NeoPixel Ring simple sketch (c) 2013 Shae Erisson
// Released under the GPLv3 license to match the rest of the
// Adafruit NeoPixel library

#include <Adafruit_NeoPixel.h>
#ifdef __AVR__
 #include <avr/power.h> // Required for 16 MHz Adafruit Trinket
#endif

// Which pin on the Arduino is connected to the NeoPixels?
#define PIN        6 // On Trinket or Gemma, suggest changing this to 1

// How many NeoPixels are attached to the Arduino?
#define NUMPIXELS 16 // Popular NeoPixel ring size

// When setting up the NeoPixel library, we tell it how many pixels,
// and which pin to use to send signals. Note that for older NeoPixel
// strips you might need to change the third parameter -- see the
// strandtest example for more information on possible values.
Adafruit_NeoPixel pixels(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);

#define DELAYVAL 500 // Time (in milliseconds) to pause between pixels

void setup() {
  // These lines are specifically to support the Adafruit Trinket 5V 16 MHz.
  // Any other board, you can remove this part (but no harm leaving it):
#if defined(__AVR_ATtiny85__) && (F_CPU == 16000000)
  clock_prescale_set(clock_div_1);
#endif
  // END of Trinket-specific code.

  pixels.begin(); // INITIALIZE NeoPixel strip object (REQUIRED)
}

void loop() {
  pixels.clear(); // Set all pixel colors to 'off'

  // The first NeoPixel in a strand is #0, second is 1, all the way up
  // to the count of pixels minus one.
  for(int i=0; i<NUMPIXELS; i++) { // For each pixel...

    // pixels.Color() takes RGB values, from 0,0,0 up to 255,255,255
    // Here we're using a moderately bright green color:
    pixels.setPixelColor(i, pixels.Color(0, 150, 0));

    pixels.show();   // Send the updated pixel colors to the hardware.

    delay(DELAYVAL); // Pause before next pass through loop
  }
}

Credits

RoboCircuits

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NeoPixel Tutorial

Things used in this project

Hardware components

Software apps and online services

Story

THE CODE

Schematics

Arduino Neopixel

Code

Arduino Neopixel

Credits

RoboCircuits

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NeoPixel Tutorial

NeoPixel Tutorial

Things used in this project

Hardware components

Software apps and online services

Story

THE CODE

Schematics

Arduino Neopixel

Code

Arduino Neopixel

Credits

RoboCircuits

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