/*  "incrementer"
 *   -This is a simple program that responds to the state
 *    of a switch. If it is closed, it increments a variable
 *    lights an LED and waits half a second. 
 *    -Otherwise it does nothing.
 *    
 *--- Set up:  > Wire a switch between pin 5 and Gnd 
 *
 *******************************************************/    

int numVariable = 0;  // Just a number variable, not connected to anything

int LEDpin = 7;       // pin number of the LED
int switchPin = 5;    // pin number of the switch
boolean swState = 0;  // create variable for storing switch "state"

 void setup() {         
   pinMode(LEDpin, OUTPUT);           // Define LED pin   
   pinMode(switchPin, INPUT_PULLUP);  // Define Switch pin as INPUT
                                      // (It's default state will be HIGH.)
   Serial.begin(9600);           // Start a serial data connection with USB 
   }

  void loop() {   
    swState = digitalRead(switchPin); // "Read" the voltage on the pin
       if (swState == LOW) {          // (If button is pressed)
         numVariable++;               // Add one  to the variable
         Serial.print("Switch closed. Variable is now: ");
         Serial.println(numVariable);
         digitalWrite(LEDpin, HIGH);  // turn LED on:
        delay(500);                   // Delay 500 milliseconds
     } 
          // Otherwise, assume the switch is open.
      else {
    digitalWrite(LEDpin, LOW);              // turn LED off:
     }
}