Arduino code to create an ambient backlight using an RGB LED ring

led-ring-backlight.ino

#include <Adafruit_NeoPixel.h>
#ifdef __AVR__
  #include <avr/power.h>
#endif

#define PIN 6 // pin on the Arduino is connected to the LED ring
#define NUMPIXELS 24 // Number of pixels on the LED ring
#define POT_PIN 0 // Potentiometer pin
#define BUTTON_PIN 2 // Button pin

Adafruit_NeoPixel pixels = Adafruit_NeoPixel(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);

int showType = 0;
bool oldState = HIGH;

void setup() {

  pinMode(BUTTON_PIN, INPUT_PULLUP); // Declare pushbutton as input
  pixels.begin(); // This initializes the NeoPixel library.
  
}

void loop() {

  // Read the potentiometer value and translate to how many pixels we want to illuminate
  int value = analogRead(POT_PIN);
  value = map(value, 0, 1023, 0, 25);

  // Switch colours if the button is pressed
  bool newState = digitalRead(BUTTON_PIN);
  if (newState == LOW && oldState == HIGH) {
    delay(20); // Short delay to debounce button.

    // Check if button is still low after debounce.
    newState = digitalRead(BUTTON_PIN);
    if (newState == LOW) {
	  // Cycle through different colour schemes
      showType++;
      if (showType > 8) showType=0;
    }
  }
  oldState = newState; // Set the last button state to the old state.
  
  uint32_t color = pixels.Color(255,255,255); // default to white when first booted

  if (showType==1) color = pixels.Color(0,0,255); // blue
  if (showType==2) color = pixels.Color(0,255,0); // green
  if (showType==3) color = pixels.Color(255,0,0); // red
  if (showType==4) color = pixels.Color(0,127,255);
  if (showType==5) color = pixels.Color(255,127,0);
  if (showType==6) color = pixels.Color(255,0,127);
  if (showType==7) color = pixels.Color(0,255,255);
  if (showType==8) color = pixels.Color(127,127,255);

  // Illuminate X pixels depending on how far the potentiometer is turned
  for(int i=0;i<NUMPIXELS;i++){
    if (i<value) {
      pixels.setPixelColor(i, color);
    } else {
      pixels.setPixelColor(i, pixels.Color(0,0,0)); // Don't show anything
    }
  }
  
  pixels.show(); // This sends the updated pixel configuration to the hardware.
 
}