Managing an LED in PHP

Now it's time to see how to manage our LED using the PHP language.

There are two different possibilities to do this: the first one is to use the LAMP (Linux-Apache-MySQL-PHP) system we set up in The LAMP suite section of Chapter 1, Installing the Developing System, while the second one is to use the PHP built-in web server.

The LAMP solution

This is the easiest and most classic way to implement a common web application. We just need a PHP script where we can implement our LED management. So let's start with writing some code!

In the first step, we must create a file named turn.php in the /var/www/ directory of the BeagleBone Black with the following content:

<?php
        # 1st part - Global defines & functions
        define("value_f", "/sys/class/gpio/gpio66/value");

        # 2nd part - Get the current led status
        $led_status = intval(file_get_contents(value_f));

        # 3rd part - Render the led status by HTML code
?...