Use PHP and MQTT to implement remote monitoring of environmental data and alarm functions

Use PHP and MQTT to realize remote monitoring of environmental data and alarm functions

With the continuous development of Internet of Things technology, remote monitoring of environmental data and alarm functions have been widely used in various fields. This article will introduce how to use PHP and MQTT protocols to implement remote monitoring of environmental data and alarm functions, and provide code examples to help readers better understand and apply.

1. Introduction to MQTT protocol

MQTT is a lightweight instant messaging protocol that is suitable for various network connections and devices. The MQTT protocol adopts a publish-subscribe model. The sender of the message (publisher) sends the message to a specific topic (Topic), and the subscriber can choose to subscribe to the topic of interest to receive the message.

2. Environment setup

1. Install the MQTT server

First, we need to install the MQTT server. You can choose the open source Mosquitto or other ones that support the MQTT protocol. server. You can choose the appropriate installation method according to your operating system.

2. PHP Installation and Configuration

Next, we need to install PHP and make sure that the PHP extension for MQTT is installed. You can use the following command to install the MQTT PHP extension:

pecl install Mosquitto-alpha

After the installation is complete, we need to add the extension to the PHP configuration file. Add the following line to php.ini:

extension=mosquitto.so

3. Write PHP code

The following is an example PHP code that implements remote monitoring of environmental data and alarm functions. In the code, we implement the data publishing and subscribing functions through the MQTT protocol.

<?php
// 连接MQTT服务器
$mqtt = new MosquittoClient();
$mqtt->connect('localhost', 1883, 60);

// 订阅主题
$mqtt->subscribe('environment/sensor1/temperature');
$mqtt->subscribe('environment/sensor1/humidity');

// 发布环境数据
function publishEnvironmentData($topic, $data) {
    global $mqtt;
    $mqtt->publish($topic, $data, 0, false);
}

// 处理收到的消息
function handleMessage($message) {
    $topic = $message->topic;
    $payload = $message->payload;
    
    if ($topic == 'environment/sensor1/temperature') {
        // 处理温度数据
        if ($payload > 30) {
            sendAlert('温度过高：'.$payload);
        }
    } elseif ($topic == 'environment/sensor1/humidity') {
        // 处理湿度数据
        if ($payload > 80) {
            sendAlert('湿度过高：'.$payload);
        }
    }
}

// 发送报警通知
function sendAlert($message) {
    // 发送报警通知的逻辑
    // 比如发送邮件、短信、推送等
    // ...
    echo '报警通知：'.$message.PHP_EOL;
}

// 设置消息回调函数
$mqtt->onMessage(function($message) {
    handleMessage($message);
});

// 循环处理消息
while (true) {
    $mqtt->loop();
}

4. Run the code

Save the above code as monitor.php, and then run the following command on the command line to start the PHP script:

php monitor.php

When there is temperature or humidity When the data exceeds the threshold, you will receive an alarm notification. You can modify the parameters and logic in the code according to your own needs.

This article introduces how to use PHP and MQTT protocols to implement remote monitoring of environmental data and alarm functions, and provides code examples. I hope this article can be helpful to readers and allow them to better apply IoT technology and achieve better remote monitoring and alarm functions.

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