FastLED RGB & HSV Tutorial

FastLED-RGB-HSV-Tutorial.ino

#include "FastLED.h"

// How many leds in your strip?
#define NUM_LEDS 8

// Data pin for the LEDs
#define DATA_PIN 17

// Potentiometer pins
#define POT_0_PIN A0
#define POT_1_PIN A1
#define POT_2_PIN A2

// Switch pin
#define SWITCH_PIN 9

// Push button pin
#define BUTTON_PIN 2

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

// setup is called once by Arduino automatically
// all initial setup work should be done here
void setup() {
  // start the serial port, so we can log data to the Arduino IDE
  Serial.begin(9600);
  
  // start FastLED, tell it about our LEDs
  FastLED.addLeds<WS2811, DATA_PIN, GRB>(leds, NUM_LEDS);
  
  // set the LED brightness
  // this is a global brightness, applied regardless of what color(s) are shown on the LEDs
  FastLED.setBrightness(64);

  // set the switch and button pins to input mode (as opposed to output), since we'll be reading from them
  pinMode(SWITCH_PIN, INPUT);
  pinMode(BUTTON_PIN, INPUT);
}

void loop() {
  int value0 = analogRead(A0); // read the value from the first potentiometer
  int value1 = analogRead(A1); // read the value from the second potentiometer
  int value2 = analogRead(A2); // read the value from the third potentiometer

  // read whether the button is pressed
  boolean buttonIsPressed = digitalRead(BUTTON_PIN) == HIGH;
  
  // read whether the switch is on or off
  boolean switchIsOn = digitalRead(SWITCH_PIN) == HIGH;

  // scale the potentiometer values from 10-bit (0-1023) to 8-bit (0-255)
  byte byte0 = map(value0, 0, 1023, 0, 255); // scale the value of first potentiometer
  byte byte1 = map(value1, 0, 1023, 0, 255); // scale the value of second potentiometer
  byte byte2 = map(value2, 0, 1023, 0, 255); // scale the value of third potentiometer

  // log the scaled potentiomenter values to the Serial port
  printValues(byte0, byte1, byte2);

  // if the button is pressed, show rainbows!
  if (buttonIsPressed) {
    spinningRainbow();
    // adjustableRainbow(byte0, byte1, byte2);
  }
  else if (switchIsOn) {
    // if the button is not pressed, but the switch is on,
    // set the color using RGB - red, green, and blue
    setColorRGB(byte0, byte1, byte2);
  }
  else {
    // if the button is not pressed, and the switch is not on,
    // set the color using HSV - hue, saturation, and value (or brightness)
    setColorHSV(byte0, byte1, byte2);
  }

  // use FastLED to show the color(s) we've set
  FastLED.show();
}

void setColorRGB(byte r, byte g, byte b) {
  // create a new RGB color
  CRGB color = CRGB(r, g, b);

  // use FastLED to set the color of all LEDs in the strip to the same color
  fill_solid(leds, NUM_LEDS, color);
}

void setColorHSV(byte h, byte s, byte v) {
  // create a new HSV color
  CHSV color = CHSV(h, s, v);

  // use FastLED to set the color of all LEDs in the strip to the same color
  fill_solid(leds, NUM_LEDS, color);
}

// show a spinning or scrolling rainbow
void spinningRainbow() {
  // variable used for the initial hue of the rainbow
  // we start it out at 0
  // but since it's static, it'll keep it's value as we change it
  static byte initialHue = 0;
  
  // increase the hue by 1 each time
  initialHue = initialHue + 1;
  
  // the amount we want the hue to change between each LED
  // by dividing the number of hues (255), by the number of LEDs,
  // this code makes each LED a different color
  // and covers the entire rainbow spectrum (red, orange, yellow, green, blue, indigo, violet)
  byte changeInHue = 255 / NUM_LEDS;
  
  // use FastLED to fill the LEDs with a rainbow
  fill_rainbow(leds, NUM_LEDS, initialHue, changeInHue);
}

// show a rainbow that is adjustable by the potentiometers
void adjustableRainbow(byte numToFill, byte initialHue, byte changeInHue) {
  // the "red" or "hue" knob will be used to set how many LEDs to fill with the rainbow
  numToFill = map8(numToFill, 1, NUM_LEDS);

  // the amount the color's hue will change between each LED
  // we need to remap this from 0-255 to between 0 and the number of LEDs we have
  changeInHue = map8(changeInHue, 8, 255 / NUM_LEDS);

  // set all LEDs to black
  FastLED.clear(); 

  // use FastLED to fill the LEDs with the rainbow
  fill_rainbow(leds, numToFill, initialHue, changeInHue);
}

void printValues(int value0, int value1, int value2) {
  // keep track of the former values, so we can log only when they change
  // since these are static, they'll keep their value between calls
  static int lastValue0 = 0;
  static int lastValue1 = 0;
  static int lastValue2 = 0;

  // if any of the values have changed
  if (value0 != lastValue0 || value1 != lastValue1 || value2 != lastValue2) {
    // print the new values to the Serial port
    Serial.print(value0);
    Serial.print(", "); Serial.print(value1);
    Serial.print(", "); Serial.print(value2);
    Serial.println("");

    // store the new values
    lastValue0 = value0;
    lastValue1 = value1;
    lastValue2 = value2;
  }
}