/*
  Analog Input
 Demonstrates analog input by reading an analog sensor on analog pin 3 (A3) and
 turning on and off a light emitting diode(LED)  connected to digital/PWM pin 3. 
 The amount of time the LED will be on and off depends on
 the value obtained by analogRead(). 
 
 The circuit:
 * Potentiometer attached to analog input 3 (A3)
 * center pin of the potentiometer to the analog pin
 * one side pin (either one) to ground
 * the other side pin to +5V
 * LED anode (long leg) attached to digital/PWM output 3
 * LED cathode (short leg) attached to ground
 
 
 */

int sensorPin = A3;    // select the input pin for the potentiometer
int ledPin = 3;      // select the pin for the LED
int sensorValue = 0;  // variable to store the value coming from the sensor

void setup() {
  // declare the ledPin as an OUTPUT:
  pinMode(ledPin, OUTPUT);  
}

void loop() {
  // read the value from the sensor:
  sensorValue = analogRead(sensorPin); 
  sensorValue = map(sensorValue,0,1023,0,255); //map scales ranges of numbers   
  // brighten and dim LED
  analogWrite(ledPin, sensorValue);    
}