APA102 Addressable LED Hookup Guide

Contributors: bboyho

Arduino Example

The FastLED library includes a few examples for a variety of addressable LED chipsets to get started. The following examples will demonstrate how to modify the example to use with the APA102 chipset. For more information, check out the FastLED Library's wiki.

FastLED Blink Modification

For simplicity, let's blink one LED from the APA102 LED strip using the FastLED's Blink.ino example by following the steps listed below. After installing the library, head to File > Examples > FastLED > Blink to open the example in Arduino.

• First, adjust the number of LEDs (NUM_LEDs) in the strip to 60.
• Change the DATA_PIN to pin 11.
• Change CLOCK_PIN to 13.
• In the setup(),
  • Comment out a line by adding // in front of FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, NUM_LEDS);.
  • Uncomment out the LED arrangement for the APA102 chipset by removing the // before FastLED.addLeds<APA102, DATA_PIN, CLOCK_PIN, RGB>(leds, NUM_LEDS);.
• Modify the color order by changing RGB to BGR.

Once the code is adjusted, select your board and COM port. Then upload the code to blink the first LED of the strand! After uploading, you should see the first LED blink with red.

Now that you have the LED blinking red, try copying and pasting the code in the loop() function two more times to see if you can blink a green and blue. This is useful to test if your APA102 is outputting the correct color before mixing the colors.

Or copy and paste the modified example in an Arduino sketch. Select the COM port and board, and hit the upload button.

language:c
#include <FastLED.h>

// How many leds in your strip?
#define NUM_LEDS 60

// For led chips like Neopixels, which have a data line, ground, and power, you just
// need to define DATA_PIN.  For led chipsets that are SPI based (four wires - data, clock,
// ground, and power), like the LPD8806 define both DATA_PIN and CLOCK_PIN
#define DATA_PIN 11
#define CLOCK_PIN 13

// Define the array of leds
CRGB leds[NUM_LEDS];

void setup() {
  // Uncomment/edit one of the following lines for your leds arrangement.
  // FastLED.addLeds<TM1803, DATA_PIN, RGB>(leds, NUM_LEDS);
  // FastLED.addLeds<TM1804, DATA_PIN, RGB>(leds, NUM_LEDS);
  // FastLED.addLeds<TM1809, DATA_PIN, RGB>(leds, NUM_LEDS);
  // FastLED.addLeds<WS2811, DATA_PIN, RGB>(leds, NUM_LEDS);
  // FastLED.addLeds<WS2812, DATA_PIN, RGB>(leds, NUM_LEDS);
  // FastLED.addLeds<WS2812B, DATA_PIN, RGB>(leds, NUM_LEDS);
  // FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, NUM_LEDS);
  // FastLED.addLeds<APA104, DATA_PIN, RGB>(leds, NUM_LEDS);
  // FastLED.addLeds<UCS1903, DATA_PIN, RGB>(leds, NUM_LEDS);
  // FastLED.addLeds<UCS1903B, DATA_PIN, RGB>(leds, NUM_LEDS);
  // FastLED.addLeds<GW6205, DATA_PIN, RGB>(leds, NUM_LEDS);
  // FastLED.addLeds<GW6205_400, DATA_PIN, RGB>(leds, NUM_LEDS);

  // FastLED.addLeds<WS2801, RGB>(leds, NUM_LEDS);
  // FastLED.addLeds<SM16716, RGB>(leds, NUM_LEDS);
  // FastLED.addLeds<LPD8806, RGB>(leds, NUM_LEDS);
  // FastLED.addLeds<P9813, RGB>(leds, NUM_LEDS);
  // FastLED.addLeds<APA102, RGB>(leds, NUM_LEDS);
  // FastLED.addLeds<DOTSTAR, RGB>(leds, NUM_LEDS);

  // FastLED.addLeds<WS2801, DATA_PIN, CLOCK_PIN, RGB>(leds, NUM_LEDS);
  // FastLED.addLeds<SM16716, DATA_PIN, CLOCK_PIN, RGB>(leds, NUM_LEDS);
  // FastLED.addLeds<LPD8806, DATA_PIN, CLOCK_PIN, RGB>(leds, NUM_LEDS);
  // FastLED.addLeds<P9813, DATA_PIN, CLOCK_PIN, RGB>(leds, NUM_LEDS);
  FastLED.addLeds<APA102, DATA_PIN, CLOCK_PIN, BGR>(leds, NUM_LEDS);
  // FastLED.addLeds<DOTSTAR, DATA_PIN, CLOCK_PIN, RGB>(leds, NUM_LEDS);
}

void loop() {
  // Turn the LED on, then pause
  leds[0] = CRGB::Red;
  FastLED.show();
  delay(500);
  // Now turn the LED off, then pause
  leds[0] = CRGB::Black;
  FastLED.show();
  delay(500);

  // Turn the LED on, then pause
  leds[0] = CRGB::Green;
  FastLED.show();
  delay(500);
  // Now turn the LED off, then pause
  leds[0] = CRGB::Black;
  FastLED.show();
  delay(500);

  // Turn the LED on, then pause
  leds[0] = CRGB::Blue;
  FastLED.show();
  delay(500);
  // Now turn the LED off, then pause
  leds[0] = CRGB::Black;
  FastLED.show();
  delay(500);
}

There's a variety of pre-defined colors in the FastLED library that you can use. Try looking at the keywords.txt to try out the different colors. Then try adjusting the array number to turn on different LEDs on the strip.

Color Palette Modification

There are a few demos with different animations in the library. Let's try looking at the color palette demo. The color palette cycles the LED strip with few different palettes. The first is a rainbow, rainbow stripes, purple and green stripes, random, white stripes, cloud-like colors, and red/white/blue stripes. There is an option to blend the LED animation for the palettes depending on your preference and project. Head to File > Examples > FastLED > ColorPalette to open the example in Arduino.

• First, comment out a line by adding // in front of #define LED_PIN 5.
• We'll define that pin by adding the following line #define DATA_PIN 11.
• We'll add an additional pin for the clock by adding the following line #define CLK_PIN 13.
• Adjust the number of LEDs (NUM_LEDS) to 60.
• Change the LED_TYPE to pin APA102.
• Modify the color order by changing GRB to BGR.
• In the setup(),
  • Comment out a line by adding // in front of FastLED.addLeds<LED_TYPE, LED_PIN, COLOR_ORDER>(leds, NUM_LEDS).setCorrection( TypicalLEDStrip );.
  • Add the LED arrangement for the APA102 chipset by adding the following line FastLED.addLeds<LED_TYPE,DATA_PIN,CLK_PIN,COLOR_ORDER>(leds, NUM_LEDS).setCorrection(TypicalLEDStrip);.

Or copy and paste the modified example in an Arduino sketch. Or copy and paste the modified example in an Arduino sketch. Select the COM port and board, and hit the upload button.

language:c
   #include <FastLED.h>

//#define LED_PIN     5 // redefined in the next line
#define DATA_PIN     11
#define CLK_PIN     13
#define NUM_LEDS    60
#define BRIGHTNESS  64
#define LED_TYPE    APA102
#define COLOR_ORDER BGR
CRGB leds[NUM_LEDS];

#define UPDATES_PER_SECOND 100

// This example shows several ways to set up and use 'palettes' of colors
// with FastLED.
//
// These compact palettes provide an easy way to re-colorize your
// animation on the fly, quickly, easily, and with low overhead.
//
// USING palettes is MUCH simpler in practice than in theory, so first just
// run this sketch, and watch the pretty lights as you then read through
// the code.  Although this sketch has eight (or more) different color schemes,
// the entire sketch compiles down to about 6.5K on AVR.
//
// FastLED provides a few pre-configured color palettes, and makes it
// extremely easy to make up your own color schemes with palettes.
//
// Some notes on the more abstract 'theory and practice' of
// FastLED compact palettes are at the bottom of this file.



CRGBPalette16 currentPalette;
TBlendType    currentBlending;

extern CRGBPalette16 myRedWhiteBluePalette;
extern const TProgmemPalette16 myRedWhiteBluePalette_p PROGMEM;


void setup() {
    delay( 3000 ); // power-up safety delay
    //FastLED.addLeds<LED_TYPE, LED_PIN, COLOR_ORDER>(leds, NUM_LEDS).setCorrection( TypicalLEDStrip );
    FastLED.addLeds<LED_TYPE,DATA_PIN,CLK_PIN,COLOR_ORDER>(leds, NUM_LEDS).setCorrection(TypicalLEDStrip);
    FastLED.setBrightness(  BRIGHTNESS );

    currentPalette = RainbowColors_p;
    currentBlending = LINEARBLEND;
}


void loop()
{
    ChangePalettePeriodically();

    static uint8_t startIndex = 0;
    startIndex = startIndex + 1; /* motion speed */

    FillLEDsFromPaletteColors( startIndex);

    FastLED.show();
    FastLED.delay(1000 / UPDATES_PER_SECOND);
}

void FillLEDsFromPaletteColors( uint8_t colorIndex)
{
    uint8_t brightness = 255;

    for( int i = 0; i < NUM_LEDS; i++) {
        leds[i] = ColorFromPalette( currentPalette, colorIndex, brightness, currentBlending);
        colorIndex += 3;
    }
}


// There are several different palettes of colors demonstrated here.
//
// FastLED provides several 'preset' palettes: RainbowColors_p, RainbowStripeColors_p,
// OceanColors_p, CloudColors_p, LavaColors_p, ForestColors_p, and PartyColors_p.
//
// Additionally, you can manually define your own color palettes, or you can write
// code that creates color palettes on the fly.  All are shown here.

void ChangePalettePeriodically()
{
    uint8_t secondHand = (millis() / 1000) % 60;
    static uint8_t lastSecond = 99;

    if( lastSecond != secondHand) {
        lastSecond = secondHand;
        if( secondHand ==  0)  { currentPalette = RainbowColors_p;         currentBlending = LINEARBLEND; }
        if( secondHand == 10)  { currentPalette = RainbowStripeColors_p;   currentBlending = NOBLEND;  }
        if( secondHand == 15)  { currentPalette = RainbowStripeColors_p;   currentBlending = LINEARBLEND; }
        if( secondHand == 20)  { SetupPurpleAndGreenPalette();             currentBlending = LINEARBLEND; }
        if( secondHand == 25)  { SetupTotallyRandomPalette();              currentBlending = LINEARBLEND; }
        if( secondHand == 30)  { SetupBlackAndWhiteStripedPalette();       currentBlending = NOBLEND; }
        if( secondHand == 35)  { SetupBlackAndWhiteStripedPalette();       currentBlending = LINEARBLEND; }
        if( secondHand == 40)  { currentPalette = CloudColors_p;           currentBlending = LINEARBLEND; }
        if( secondHand == 45)  { currentPalette = PartyColors_p;           currentBlending = LINEARBLEND; }
        if( secondHand == 50)  { currentPalette = myRedWhiteBluePalette_p; currentBlending = NOBLEND;  }
        if( secondHand == 55)  { currentPalette = myRedWhiteBluePalette_p; currentBlending = LINEARBLEND; }
    }
}

// This function fills the palette with totally random colors.
void SetupTotallyRandomPalette()
{
    for( int i = 0; i < 16; i++) {
        currentPalette[i] = CHSV( random8(), 255, random8());
    }
}

// This function sets up a palette of black and white stripes,
// using code.  Since the palette is effectively an array of
// sixteen CRGB colors, the various fill_* functions can be used
// to set them up.
void SetupBlackAndWhiteStripedPalette()
{
    // 'black out' all 16 palette entries...
    fill_solid( currentPalette, 16, CRGB::Black);
    // and set every fourth one to white.
    currentPalette[0] = CRGB::White;
    currentPalette[4] = CRGB::White;
    currentPalette[8] = CRGB::White;
    currentPalette[12] = CRGB::White;

}

// This function sets up a palette of purple and green stripes.
void SetupPurpleAndGreenPalette()
{
    CRGB purple = CHSV( HUE_PURPLE, 255, 255);
    CRGB green  = CHSV( HUE_GREEN, 255, 255);
    CRGB black  = CRGB::Black;

    currentPalette = CRGBPalette16(
                                   green,  green,  black,  black,
                                   purple, purple, black,  black,
                                   green,  green,  black,  black,
                                   purple, purple, black,  black );
}


// This example shows how to set up a static color palette
// which is stored in PROGMEM (flash), which is almost always more
// plentiful than RAM.  A static PROGMEM palette like this
// takes up 64 bytes of flash.
const TProgmemPalette16 myRedWhiteBluePalette_p PROGMEM =
{
    CRGB::Red,
    CRGB::Gray, // 'white' is too bright compared to red and blue
    CRGB::Blue,
    CRGB::Black,

    CRGB::Red,
    CRGB::Gray,
    CRGB::Blue,
    CRGB::Black,

    CRGB::Red,
    CRGB::Red,
    CRGB::Gray,
    CRGB::Gray,
    CRGB::Blue,
    CRGB::Blue,
    CRGB::Black,
    CRGB::Black
};



// Additional notes on FastLED compact palettes:
//
// Normally, in computer graphics, the palette (or "color lookup table")
// has 256 entries, each containing a specific 24-bit RGB color.  You can then
// index into the color palette using a simple 8-bit (one byte) value.
// A 256-entry color palette takes up 768 bytes of RAM, which on Arduino
// is quite possibly "too many" bytes.
//
// FastLED does offer traditional 256-element palettes, for setups that
// can afford the 768-byte cost in RAM.
//
// However, FastLED also offers a compact alternative.  FastLED offers
// palettes that store 16 distinct entries, but can be accessed AS IF
// they actually have 256 entries; this is accomplished by interpolating
// between the 16 explicit entries to create fifteen intermediate palette
// entries between each pair.
//
// So for example, if you set the first two explicit entries of a compact 
// palette to Green (0,255,0) and Blue (0,0,255), and then retrieved 
// the first sixteen entries from the virtual palette (of 256), you'd get
// Green, followed by a smooth gradient from green-to-blue, and then Blue.

You should see the sequence of colors animating along the strip. There's a few more "preset" palettes defined in the library that you can use. Try looking at the colorpalettes.cpp for more and replacing ChangePalettePeriodically()'s currentPalette value to the preset of your choice. You can also manually define your own palette of your choice depending on your project based on the pre-define colors in the keywords.txt similar to the ones defined after the loop() function.

Demo Reel Modification

Another example that we will look at is the Demo Reel. Head to File > Examples > FastLED > DemoReel100 to open the example in Arduino.

• First, adjust the DATA_PIN to pin 11.
• Uncomment the CLK_PIN by removing the // and defining it as pin 13.
• Change the LED_TYPE to pin APA102.
• Modify the color order (COLOR_ORDER) by changing GRB to BGR.
• Adjust the number of LEDs (NUM_LEDS) to 60.
• In the setup(),
  • Comment out a line by adding // in front of FastLED.addLeds<LED_TYPE,DATA_PIN,COLOR_ORDER>(leds, NUM_LEDS).setCorrection(TypicalLEDStrip);.
  • Add the LED arrangement for the APA102 chipset by removing the // in front of FastLED.addLeds<LED_TYPE,DATA_PIN,CLK_PIN,COLOR_ORDER>(leds, NUM_LEDS).setCorrection(TypicalLEDStrip);.

Or copy and paste the modified example in an Arduino sketch. Select the COM port and board, and hit the upload button.

language:c
#include <FastLED.h>

FASTLED_USING_NAMESPACE

// FastLED "100-lines-of-code" demo reel, showing just a few 
// of the kinds of animation patterns you can quickly and easily 
// compose using FastLED.  
//
// This example also shows one easy way to define multiple 
// animations patterns and have them automatically rotate.
//
// -Mark Kriegsman, December 2014

#if defined(FASTLED_VERSION) && (FASTLED_VERSION < 3001000)
#warning "Requires FastLED 3.1 or later; check github for latest code."
#endif

#define DATA_PIN    11
#define CLK_PIN     13
#define LED_TYPE    APA102
#define COLOR_ORDER BGR
#define NUM_LEDS    60
CRGB leds[NUM_LEDS];

#define BRIGHTNESS          96
#define FRAMES_PER_SECOND  120

void setup() {
  delay(3000); // 3 second delay for recovery

  // tell FastLED about the LED strip configuration
  //FastLED.addLeds<LED_TYPE,DATA_PIN,COLOR_ORDER>(leds, NUM_LEDS).setCorrection(TypicalLEDStrip);
  FastLED.addLeds<LED_TYPE,DATA_PIN,CLK_PIN,COLOR_ORDER>(leds, NUM_LEDS).setCorrection(TypicalLEDStrip);

  // set master brightness control
  FastLED.setBrightness(BRIGHTNESS);
}


// List of patterns to cycle through.  Each is defined as a separate function below.
typedef void (*SimplePatternList[])();
SimplePatternList gPatterns = { rainbow, rainbowWithGlitter, confetti, sinelon, juggle, bpm };

uint8_t gCurrentPatternNumber = 0; // Index number of which pattern is current
uint8_t gHue = 0; // rotating "base color" used by many of the patterns

void loop()
{
  // Call the current pattern function once, updating the 'leds' array
  gPatterns[gCurrentPatternNumber]();

  // send the 'leds' array out to the actual LED strip
  FastLED.show();  
  // insert a delay to keep the framerate modest
  FastLED.delay(1000/FRAMES_PER_SECOND); 

  // do some periodic updates
  EVERY_N_MILLISECONDS( 20 ) { gHue++; } // slowly cycle the "base color" through the rainbow
  EVERY_N_SECONDS( 10 ) { nextPattern(); } // change patterns periodically
}

#define ARRAY_SIZE(A) (sizeof(A) / sizeof((A)[0]))

void nextPattern()
{
  // add one to the current pattern number, and wrap around at the end
  gCurrentPatternNumber = (gCurrentPatternNumber + 1) % ARRAY_SIZE( gPatterns);
}

void rainbow() 
{
  // FastLED's built-in rainbow generator
  fill_rainbow( leds, NUM_LEDS, gHue, 7);
}

void rainbowWithGlitter() 
{
  // built-in FastLED rainbow, plus some random sparkly glitter
  rainbow();
  addGlitter(80);
}

void addGlitter( fract8 chanceOfGlitter) 
{
  if( random8() < chanceOfGlitter) {
    leds[ random16(NUM_LEDS) ] += CRGB::White;
  }
}

void confetti() 
{
  // random colored speckles that blink in and fade smoothly
  fadeToBlackBy( leds, NUM_LEDS, 10);
  int pos = random16(NUM_LEDS);
  leds[pos] += CHSV( gHue + random8(64), 200, 255);
}

void sinelon()
{
  // a colored dot sweeping back and forth, with fading trails
  fadeToBlackBy( leds, NUM_LEDS, 20);
  int pos = beatsin16( 13, 0, NUM_LEDS-1 );
  leds[pos] += CHSV( gHue, 255, 192);
}

void bpm()
{
  // colored stripes pulsing at a defined Beats-Per-Minute (BPM)
  uint8_t BeatsPerMinute = 62;
  CRGBPalette16 palette = PartyColors_p;
  uint8_t beat = beatsin8( BeatsPerMinute, 64, 255);
  for( int i = 0; i < NUM_LEDS; i++) { //9948
    leds[i] = ColorFromPalette(palette, gHue+(i*2), beat-gHue+(i*10));
  }
}

void juggle() {
  // eight colored dots, weaving in and out of sync with each other
  fadeToBlackBy( leds, NUM_LEDS, 20);
  byte dothue = 0;
  for( int i = 0; i < 8; i++) {
    leds[beatsin16( i+7, 0, NUM_LEDS-1 )] |= CHSV(dothue, 200, 255);
    dothue += 32;
  }
}

The LEDs will begin animating based on the functions defined in the demo. Read through the example code to see how they were written or bask in the glow of the animations running along the strip.

More Examples!

Now that we have some experience using three examples, try modifying and testing out the other code included the FastLED library!

Or you can check out the Lumenati, LuMini ring, and LuMini matrix guides that use the FastLED library.