Reference   Language | Libraries | Comparison | Changes


A boolean holds one of two values, true or false. (Each boolean variable occupies one byte of memory.)


int LEDpin = 5;       // LED on pin 5
int switchPin = 13;   // momentary switch on 13, other side connected to ground

boolean running = false;

void setup()
  pinMode(LEDpin, OUTPUT);
  pinMode(switchPin, INPUT);
  digitalWrite(switchPin, HIGH);      // turn on pullup resistor

void loop()
  if (digitalRead(switchPin) == LOW)
  {  // switch is pressed - pullup keeps pin high normally
    delay(100);                        // delay to debounce switch
    running = !running;                // toggle running variable
    digitalWrite(LEDpin, running)      // indicate via LED

See also

Reference Home

Corrections, suggestions, and new documentation should be posted to the Forum.

The text of the Arduino reference is licensed under a Creative Commons Attribution-ShareAlike 3.0 License. Code samples in the reference are released into the public domain.