Takes a potentiometer reading and controls dimness of 3 LEDs

AnalogInOutSerialThreeLED

// These constants won't change.  They're used to give names
// to the pins used:
const int analogInPin = A0;  // Analog input pin that the potentiometer is attached to
const int greenOutPin = 9; // Analog output pin that the  green LED is attached to
const int yellowOutPin = 10; // Analog output pin that the  ylw LED is attached to
const int redOutPin = 11; // Analog output pin that the  red LED is attached to

int sensorValue = 0;        // value read from the pot
int outputValue = 0;        // value output to the PWM (analog out)

void setup() {
  // initialize serial communications at 9600 bps:
  Serial.begin(9600); 
}

void loop() {
  // read the analog in value:
  sensorValue = analogRead(analogInPin);            
  // map it to the range of the analog out:
  outputValue = map(sensorValue, 0, 1023, 0, 767);
  
  // light green LED:
  if(outputValue <= 255) {
    analogWrite(greenOutPin, outputValue);
    analogWrite(yellowOutPin, 0);
    analogWrite(redOutPin, 0);
  }
  // light green and yellow LEDs:
  else if(outputValue <= 511) {
    analogWrite(yellowOutPin, outputValue - 256);
    analogWrite(greenOutPin, 255);
    analogWrite(redOutPin, 0);
  }
  // light all LEDs:
  else {
    analogWrite(redOutPin, outputValue - 512);
    analogWrite(yellowOutPin, 255);
    analogWrite(greenOutPin, 255);
  }          

  // print the results to the serial monitor:
  Serial.print("sensor = " );                       
  Serial.print(sensorValue);      
  Serial.print("\t output = ");      
  Serial.println(outputValue);   

  // wait 2 milliseconds before the next loop
  // for the analog-to-digital converter to settle
  // after the last reading:
  delay(2);                     
}