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FastLED RGB & HSV Tutorial
#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
// 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
// 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
// set the switch and button pins to input mode (as opposed to output), since we'll be reading from them
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) {
// 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;
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
// 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(", "); Serial.print(value1);
Serial.print(", "); Serial.print(value2);
// store the new values
lastValue0 = value0;
lastValue1 = value1;
lastValue2 = value2;
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