How to use PHP for basic embedded device control-PHP Tutorial-php.cn

How to use PHP for basic embedded device control

PHPz

Release： 2023-06-23 11:34:01

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Embedded device control has always been a very important field. With the development of the times, people are making more and more use of embedded devices, and the demand for controlling embedded devices is also increasing. In the control of embedded devices, PHP, as an efficient programming language, can achieve good control.

PHP is a scripting language widely used in web development. However, in the field of embedded devices, the application of PHP has gradually expanded. PHP has a wide range of application scenarios. For example, serial port communication through PHP, Web front-end control through PHP, and control through the combination of PHP and GPIO are all very common application scenarios.

Below we focus on how to use PHP to implement basic embedded device control.

1. Install PHP

The installation of PHP is very simple, just enter the following command in the terminal:

sudo apt-get install php

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The above command installs PHP through the apt-get command, This is a commonly used command under Linux and is also very simple.

2. Communication with serial port through PHP

Serial communication is a relatively basic operation in embedded device control. Many basic operations can be realized through PHP and serial port communication. The following uses a simple application scenario to introduce how to communicate with the serial port through PHP.

Suppose there is an embedded device that has two GPIO ports, one is used to control the LED on and off, and the other is used to read the status of the switch. We need to communicate with this device through the serial port to achieve remote control.

The following is a code example for PHP and serial port communication:

<?php
    // 打开串口
    $serial = fopen("/dev/ttyACM0", "w+");
    // 发送命令
    fwrite($serial, "LED ON");
    // 读取返回值
    $response = fread($serial, 10);
    // 关闭串口
    fclose($serial);
?>

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The above code realizes PHP and serial port communication by opening the serial port, sending commands, reading the return value, and closing the serial port. Among them, /dev/ttyACM0 is the name of the serial port, which needs to be modified according to the actual situation in actual applications.

Control through the combination of PHP and GPIO

In embedded device control, GPIO plays a very important role. It can control external devices, such as LED lights and buzzers. Devices and so on. The following is a simple code example for controlling LED lights:

<?php
    //设置GPIO17为输出口
    system("gpio mode 0 out");
    //点亮LED灯
    system("gpio write 0 1");
    //关灯
    system("gpio write 0 0");
?>

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In the above code, we execute some commands to control GPIO through the system function to control the LED lights.

Web front-end control of embedded devices through PHP

In actual embedded device control, it is usually necessary to combine the Web front-end to control the operation of embedded devices. The following is a simple Web front-end control code example:

<!DOCTYPE html>
<html>
<head>
    <title>LED Control</title>
</head>
<body>
    <form action="led_control.php" method="post">
        <input type="radio" name="state" value="on">LED On<br>
        <input type="radio" name="state" value="off">LED Off<br>
        <input type="submit" value="Submit">
    </form>
</body>
</html>

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The above code implements the operation of controlling LED lights through a simple HTML form. When the user clicks the submit button, a POST request will be sent to led_control.php , led_control.php controls the LED according to the status selected by the user.

The following is the led_control.php code:

<?php
    if(isset($_POST['state'])) {
        if($_POST['state'] == "on") {
            system("gpio write 0 1");
        } else {
            system("gpio write 0 0");
        }
    }
?>

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The above code controls the on and off of the LED light by judging the state selected by the user.

Summary:

Through some simple examples above, we can see that PHP can be well used to control embedded devices. It is precisely because of PHP's high efficiency and ease of use that it is widely used in embedded device control. Of course, the application scenarios of PHP are far more than this. In the future, more embedded devices will be combined with PHP, bringing more convenience to people's lives and work.

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