{"id":2523,"date":"2017-06-01T09:44:08","date_gmt":"2017-06-01T08:44:08","guid":{"rendered":"http:\/\/www.robertprice.co.uk\/robblog\/?p=2523"},"modified":"2017-06-01T16:30:53","modified_gmt":"2017-06-01T15:30:53","slug":"controlling-a-led-on-a-raspberry-pi-with-php","status":"publish","type":"post","link":"https:\/\/www.robertprice.co.uk\/robblog\/controlling-a-led-on-a-raspberry-pi-with-php\/","title":{"rendered":"Controlling a LED on a Raspberry Pi with PHP"},"content":{"rendered":"

I wanted to make a LED light up using PHP on a Raspberry Pi<\/a>. Most of the examples I’ve seen are for Python<\/a>, so I wanted to see if was possible or not.<\/p>\n

It is actually pretty easy to do, so I thought I’d share my work.<\/p>\n

The first thing to do is to wire up the LED to the Raspberry Pi. I used a breadboard so there is no soldering required.<\/p>\n

\"\"<\/p>\n

Connect the LED to GPIO pin 18, along with a 330ohm resistor, to GND. We need the resistor to limit the current through the LED otherwise it could burn out.<\/p>\n

That’s the LED attached to Raspberry Pi, now we need to control it with PHP code.<\/p>\n

PHP LED Control Code<\/h2>\n

Before we can write any PHP, we need to enable the gpio module on the Raspberry Pi.<\/p>\n

sudo modprobe w1-gpio<\/code><\/p>\n

We need a third party PHP library to be able to talk to the GPIO pins. I’m using php-gpio<\/a>.<\/p>\n

We need to install this with Composer<\/a> before we can use it.<\/p>\n

\r\nget http:\/\/getcomposer.org\/composer.phar\r\nphp composer.phar require ronanguilloux\/php-gpio\r\n<\/pre>\n
We can now start our PHP code by using the autoloader to bring in the GPIO library.<\/p>\n
\r\nrequire 'vendor\/autoload.php';\r\n\r\nuse PhpGpio\\Gpio;\r\n$gpio = new GPIO();\r\n<\/pre>\n
Now to control the LED we need to make sure GPIO pin 18 is set to “out”.<\/p>\n
\r\n$gpio->setup(18, 'out');\r\n<\/pre>\n
To turn the LED on we write the value “1” to pin 18.<\/p>\n
\r\n$gpio->output(18, 1);\r\n<\/pre>\n
To turn the LED off we write the value “0” to pin 18.<\/p>\n
\r\n$gpio->output(18, 0);\r\n<\/pre>\n
Finally, we need to make sure we clean up after ourselves.<\/p>\n
\r\n$gpio->unexportAll();\r\n<\/pre>\n
The Final Code<\/h2>\n
Bringing this all together, we can write a simple PHP script to turn the LED on, wait 1 second, and turn it off again.<\/p>\n
\r\n<?php\r\n\r\nrequire 'vendor\/autoload.php';\r\n\r\nuse PhpGpio\\Gpio;\r\n$gpio = new GPIO();\r\n$gpio->setup(18, 'out');\r\n\r\necho \"LED on\\n\";\r\n$gpio->output(18, 1);\r\n\r\nsleep(1);\r\n\r\necho \"LED off\\n\";\r\n$gpio->output(18, 0);\r\n\r\n$gpio->unexportAll();\r\n<\/pre>\n
The final code needs to be run as root to be able to access gpio.<\/p>\n","protected":false},"excerpt":{"rendered":"
I wanted to make a LED light up using PHP on a Raspberry Pi. Most of the examples I’ve seen are for Python, so I wanted to see if was possible or not. It is actually pretty easy to do, so I thought I’d share my work. The first thing to do is to wire … Continue reading “Controlling a LED on a Raspberry Pi with PHP”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":2531,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"footnotes":""},"categories":[84],"tags":[87,86,50,85],"class_list":["post-2523","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-hardware","tag-gpio","tag-led","tag-php","tag-raspberry-pi"],"yoast_head":"\nControlling a LED on a Raspberry Pi with PHP - Robert Price<\/title>\n<meta name=\"description\" content=\"Using PHP to turn on and turn off a LED on a Raspberry Pi. 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