/*     ---------------------------------------------------------
 *     |  Arduino Experimentation Kit Example Code             |
 *     |  CIRC-07 .: Button Pushing :. (Pushbuttons)           |
 *     ---------------------------------------------------------
 *  A simple program that will fade the LED up when you press the top
 *  button and fade it down when you press the bottom button
 * 
 * http://tinyurl.com/c64tmt
 *
 */

//Button Variables
int buttonOne = 2; //The pin button one is attached to
int buttonTwo = 3; //The pin button one is attached to

//Led Variables
int ledPin = 9;  //The pin the LED is attached to
int ledValue = 0; //The current illumination Level of the led (0 off 255 full on)

/*
 * setup() - this function runs once when you turn your Arduino on
 * Set the pins to their appropriate states
 */
void setup()
{
  pinMode(buttonOne, INPUT); digitalWrite(buttonOne, HIGH);  //Sets the buttonOne pin to input and
                                                             //sets the Arduinos internal pullup resistor
                                                             //(this means the pin will read HIGH by default
                                                             //and LOW when you press the button pulling to ground)
  pinMode(buttonTwo, INPUT); digitalWrite(buttonTwo, HIGH);  //Sets the buttonOne pin to input and
                                                             //sets the Arduinos internal pullup resistor
  pinMode(ledPin, OUTPUT);                                                             
}
 
/*
 * loop() - this function will start after setup finishes and then repeat
 * we will increase the brightness if buttonOne is pressed and decrease the
 * brightness if buttonTwo is pressed.
 */
void loop()                     // run over and over again
{
  if(digitalRead(buttonOne) == LOW){ledValue++;}
  if(digitalRead(buttonTwo) == LOW){ledValue--;}
  ledValue = constrain(ledValue,0,255);
  analogWrite(ledPin, ledValue);
  delay(5);
}