PHP in the Hardware World: How to Write Embedded Code Without Microcontrollers

PHP and Embedded: An Unexpected Cocktail of Hardware and Scripts

When you hear "Embedded development," you usually imagine C, C++, or the latest Rust. PHP, on the other hand, is associated with websites, CMS, and sticky forms. But what if I told you that PHP can control LEDs, poll temperature sensors, or even work with the I2C bus? Yes, this is no joke. At the intersection of the web and embedded systems, there is a whole niche — Embedded development in PHP.

Of course, no one suggests writing Linux drivers in PHP. It's about something else: when you need to quickly set up a web interface for a smart home, an IoT device prototype, or automate data collection from industrial equipment — PHP turns out to be the ideal glue. It runs on Linux, easily reads/writes to device files, and its libraries allow communication with COM ports, GPIO, and even Arduino. Let's look at real scenarios of using PHP in Embedded systems, with code and practical tips.

Why PHP for Embedded? Myths and Reality

The main argument of opponents: "PHP is slow and not suitable for real-time." And this is true if you are trying to control a stepper motor with microsecond precision. But in real life, 90% of Embedded tasks do not require hard real-time. Collecting data from a sensor once per second, logging temperature, sending a command via UART — PHP does all of this easily.

Advantages of Embedded development with PHP:

• Quick start — no need to learn pointers and memory management in C. You just open a file and write.
• Web interface "out of the box" — any PHP script can be immediately wrapped in HTML+CSS+JS.
• Huge community — there are ready-made libraries for working with hardware (php-serial, php-gpio, php-i2c).
• Cross-platform — the script works on Raspberry Pi, Orange Pi, and regular PCs with Linux.

There are also downsides: PHP is not suitable for high-load systems with frequent interrupts. But for prototyping, smart homes, or industrial monitoring — it's an excellent choice.

Working with GPIO via PHP: Blinking LEDs

The simplest way to "touch" hardware is to control GPIO pins on a Raspberry Pi or Orange Pi. In Linux, GPIO are presented as files in /sys/class/gpio/. PHP can open them like regular text files. Here's an example of blinking an LED with PHP:

<?php// Define the GPIO pin number (e.g., GPIO17 — physical pin 11 on RPi)$gpio_pin = 17;

// Export the pin (if not already exported)if (!file_exists("/sys/class/gpio/gpio$gpio_pin")) {    file_put_contents("/sys/class/gpio/export", $gpio_pin);}

// Set direction — outputfile_put_contents("/sys/class/gpio/gpio$gpio_pin/direction", "out");

// Blink 5 timesfor ($i = 0; $i < 5; $i++) {    // Turn on (1)    file_put_contents("/sys/class/gpio/gpio$gpio_pin/value", "1");    sleep(1);    // Turn off (0)    file_put_contents("/sys/class/gpio/gpio$gpio_pin/value", "0");    sleep(1);}

// Unexport the pinfile_put_contents("/sys/class/gpio/unexport", $gpio_pin);echo "LED blinking finished!";?>

This code is the foundation for any device control via PHP. You can easily add button reading (just change direction to "in" and read the value). Thus, PHP turns into a full-fledged tool for working with discrete signals.

Using the php-gpio Library

To avoid writing export/unexport every time, use a ready-made library. Install it via Composer:

composer require piwik/gpio

Example with the same library:

<?phprequire 'vendor/autoload.php';

use Piwik\\Gpio\\Gpio;

$gpio = new Gpio();$pin = $gpio->getPin(17);

// Configure as output$pin->setDirection(Gpio::DIRECTION_OUT);

// Turn on