const int BUTTON_PIN = 0; // the number of the pushbutton pin const int LED_PIN = 1; // the number of the LED pin // variables will change: int buttonState = 0; // variable for reading the pushbutton status void setup() { // initialize the LED pin as an output: pinMode(LED_PIN, OUTPUT); // initialize the pushbutton pin as an pull-up input: // the pull-up input pin will be HIGH when the switch is open and LOW when the switch is closed. pinMode(BUTTON_PIN, INPUT_PULLUP); } void loop() { // read the state of the pushbutton value: buttonState = digitalRead(BUTTON_PIN); // control LED according to the state of button if(buttonState == LOW) // If button is pressing digitalWrite(LED_PIN, HIGH); // turn on LED else // otherwise, button is not pressing digitalWrite(LED_PIN, LOW); // turn off LED }