php-linux-gpio/examples/buttons.php

<?php

require_once __DIR__."/../vendor/autoload.php";
require_once __DIR__."/GLOBALS.php";

use NoccyLabs\Gpio\Gpio;
use NoccyLabs\Gpio\GpioMapper\WiringPiMapper;

try {
    $gpio = new Gpio();
} catch (Gpio\Exception $e) {
    error_log("Error: {$e}");
}

// The mapper translates GPIO to logical pins and vice versa
$gpio->setMapper( new WiringPiMapper(2) );

// Access logical pin 0, since we got a mapper assigned. Otherwise this would
// be the actual GPIO0 pin.
$led = $gpio[0]
    ->export()
    ->setDirection("output")
    ->setValue(0)
    ->setLabel("red led")
    ->dumpStatus(true);

$btn1 = $gpio[1]
    ->setDirection("input")
    ->setValue(0)
    ->setEdge("rising")
    ->setHandler(function() { echo "INTERRUPT!\n"; })
    ->setLabel("button 1")
    ->dumpStatus(true);

$btn2 = $gpio[2]
    ->setDirection("input")
    ->setValue(0)
    ->setEdge("rising")
    ->setHandler(function() { echo "INTERRUPT!\n"; })
    ->setLabel("button 2")
    ->dumpStatus(true);