int buttonPin = 7;        // the pushbutton is on pin D7 of the ThinkerShield
int ledPin = 12;          // the LED is on pin D12
int buttonState = 0;      // variable for reading the pushbutton's state

void setup() {
  pinMode(ledPin, OUTPUT);     // the LED pin is an output
  pinMode(buttonPin, INPUT);   // the button pin is an input
}

void loop() {
  buttonState = digitalRead(buttonPin);   // read the button
  if (buttonState == HIGH) {              // is it pressed?
    digitalWrite(ledPin, HIGH);           // yes -> LED on
  } else {
    digitalWrite(ledPin, LOW);            // no  -> LED off
  }
}