NeoPixel

#include "FastLED.h" // Loads FastLED library #define NUM_LEDS 20 // How many NeoPixels on your strip? #define DATA_PIN 3 // Data pin from microcontroller connected to LED strip #define BUTTON_PIN 4 // Data pin to read button state #define BUTTON_GND 6 // Data pin providing ground source to button, since we have limited mounting options for the Metro-Mini #define KNOB_PIN A0 // analog input pin that is connected to the center pin of potentiometer, where pot position will be measured #define KNOB_GND A1 // analog input pin that is connected to one side of potentiometer, and will be needed to supply ground int buttonPressed = 1; // initial state of push button, since input is pulled high and we need to declare variable scope. CRGB leds[NUM_LEDS]; // Tells the Library how many pixels we have void setup() { // put your setup code here, to run once: FastLED.addLeds<NEOPIXEL,DATA_PIN>(leds, NUM_LEDS); // this specifies the configuration for the FastLED library pinMode(KNOB_GND, OUTPUT); // configures Analog pin to be an output... digitalWrite(KNOB_GND, LOW); // ...and writes a zero/low, to supply ground to the potentiometer pinMode(BUTTON_PIN, INPUT_PULLUP); // configures the digital pin for the button to be an input, and enable the internal pullup resistor pinMode(BUTTON_GND, OUTPUT); // configures the digital pin for the button ground to be an output... digitalWrite(BUTTON_GND, LOW); // ...and writes a zero/low, to supply ground to the button } void loop() { // put your main code here, to run repeatedly: int val = analogRead(KNOB_PIN); // reads the analog voltage of the potentiometer int colorOfLed = map(val, 0, 1023, 0, 255); // this map function takes the 10-bit value read from potentiometer and converts to 8-bit value that can be used for the hue leds[0].setHSV( colorOfLed, 255, 200); // sets the first NeoPixel to the hue of the potentiometer, with full color saturation and 200 brightness FastLED.show(); // sends the above data to the NeoPixels buttonPressed = digitalRead(BUTTON_PIN); // read and store button state if (buttonPressed == LOW) { // logic check if button is currently pressed for (int i = 1; i < NUM_LEDS; i++) { // this for loop starts at second pixel (1), then increments pixels until until it reachs the last LED on the strip leds[i] = CHSV( colorOfLed, 255, 200); // sets the incremented pixel to the hue set by pot, full color saturation, 200 brightness FastLED.show(); // writes data to the NeoPixels leds[i-1] = CRGB::Black; // blanks out the previous pixel FastLED.show(); // writes data to the NeoPixels FastLED.delay(15); // delays 15ms between movement of each pixel } FastLED.clear(); // turns off the pixels, and writes immediately, when the pixel animation loop above completes } }