Code for the LED meter project. Sparkle Labs / Discover Arduino Bundle

ledmeter.ino

// Sparkle Labs / Discover Arduino Bundle
// LED Meter Project
// ---------------------------------------
// Increment 3 LEDs by turning a knob.
//
// Circuit: 
// Pins 0, 1, 2 are connected to ground through 3 LED drivers.
// A potentiometer is connected to power and ground on either side with the center pin (wiper) connected to Pin A0 on the Arduino.
//
// Parts:
// 3 LEDs
// 3 Resistors (100 - 220 ohms)
// 1 Potentiometer
//
// Schematic:
//                                                                                     
//                     +5V -----------------------------+                              
//                                                      |                              
//                                      +---------------|--------Resistor-->LED---+    
//                                      | +-------------|-----+                   |    
//                                      | | +-----------|--+  +--Resistor-->LED---O    
//      +-------------------------------+-+-+---+       |  |                      |    
//      |       G 1 1 1 1 9 8 7 6 5 4 3 2 1 0   |       |  +-----Resistor-->LED---O    
//      |       N 3 2 1 0                       |       |                         |    
//      |                                       |       |                         |    
//  +---+---+   D     ~ ~ ~     ~ ~   ~         |       |                         |    
//  |       |                                   |       |                         |    
//  |  USB  |                                   +-+     |                         |    
//  +---+---+               +---------------+     |     |                         |    
//      |                   | ARDUINO  UNO  |     |     |     +---------------+   |    
//      |                   +---------------+     |     |     |               |   |    
//      |                                         |     |     | Potentiometer |   |    
//      |                 G G                     |     |     |               |   |    
//      |               5 N N     A A A A A A     |     |     +---+---+---+---+   |    
//      |               V D D     0 1 2 3 4 5   +-+     |         |   |   +-------O    
//      +-------------------------+-------------+       +---------+   |           |    
//                                |                                   |        ---+--- 
//                                +-----------------------------------+         --+--  
//                                                                               -+-   
//            *                                            

void setup() {
  pinMode(0,OUTPUT);
  pinMode(1,OUTPUT);
  pinMode(2,OUTPUT);
}

void loop() {
   // read the input on analog pin 0:
  int sensorValue = analogRead(A0);
  // The analog pin reads from 0 to 1023.
  // This commands maps those numbers from 4 to 0
  // So 0 becomes 4 and 1023 becomes 0
  int mappedSensorValue = map( sensorValue, 0, 1023, 4, 0);
  //Here we test the mappedsensorvalue. If it is greater then 1 we turn
  // on the LED on Pin 2 and then see if it is greater then 2.
    if (mappedSensorValue > 1) {
      digitalWrite ( 2, HIGH);
      if (mappedSensorValue > 2) {
          digitalWrite ( 1, HIGH);
          if (mappedSensorValue > 3) {
              digitalWrite ( 0, HIGH);
          }else{//If it is not greater we start turning LEDs off.
              digitalWrite ( 0, LOW);
          }
      }else{
          digitalWrite ( 1, LOW);
      }
    }else{
      digitalWrite ( 2, LOW);
    }
}