Arduino Starter Kit example
Project 15 - Hacking Buttons

This sketch is written to accompany Project 15 in the
Arduino Starter Kit

Parts required:
batery powered component
220 ohm resistor
4N35 optocoupler

Created 18 September 2012
by Scott Fitzgerald

This example code is part of the public domain

const int optoPin = 2; // the pin the optocoupler is connected to

void setup() {
  // make the pin with the optocoupler an output
  pinMode(optoPin, OUTPUT);

void loop() {
  digitalWrite(optoPin, HIGH);  // pull pin 2 HIGH, activating the optocoupler

  delay(15); // give the optocoupler a moment to activate

  digitalWrite(optoPin, LOW);  // pull pin 2 low until you're ready to activate again
  delay(21000);                // wait for 21 seconds