Single Pot RGB WS2812B (Neopixel) Color Change With Arduino (Using Atiny85 3.3v)

This will explain how to set up a single Pot to change through all RGB colors using the neopixel library and HSV color values with the Arduino (Any)

I assume you already have the neopixel library installed and have wired up your RGB WS2812B LED and pot to the Arduino.

#include 
#define PIN        1 //output pin to LED's
#define NUMPIXELS 4  //Number of LED's 

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


const int numReadings = 15; // Higher value will result in more stability
			    // but add more lag

int readings[numReadings];      // the readings from the analog input
int readIndex = 0;              // the index of the current reading
int total = 0;                  // the running total
int average = 0;                // the average
int x;

void loop(){
  total = total - readings[readIndex];
  readings[readIndex] = analogRead(1); //or what ever analog pin your using for the pot
  total = total + readings[readIndex];
  readIndex = readIndex + 1;
  if (readIndex >= numReadings) {
    readIndex = 0;
  }
  average = total / numReadings;
  y = map(average,0,1024,0,65536);
  
  pixels.clear(); // Set all pixel colors to 'off'
  delay(25);
  uint32_t rgbcolor = pixels.ColorHSV(y);
  pixels.fill(rgbcolor);
  pixels.show();   // Send the updated pixel colors to the hardware.

 delay(10);
  
}

The first set of code sets everything up, including initializing our variables and takes readings from our pot and averages it out giving smooth readings.

total = total - readings[readIndex];
  readings[readIndex] = analogRead(1);  //or what ever pin your using for the pot
  total = total + readings[readIndex];
  readIndex = readIndex + 1;
  if (readIndex >= numReadings) {
    readIndex = 0;
  }
  average = total / numReadings;

Next we map out the smoothed values to HSV values.

y = map(average,0,1024,0,65536); // HSV range is from 0-65536, looping back around, 
				 // starting at red and ending at red

Then we clear the pixel values and have a small delay

pixels.clear(); 
delay(25);

And finally convert the mapped pot values to HSV colors and fill all pixels with that color.

uint32_t rgbcolor = pixels.ColorHSV(y); // The main line of code that makes this all
					// possible would be converting the pot values 
					// into hsv color space
pixels.fill(rgbcolor);
pixels.show();