当前位置：首页 > news >正文

Arduino通过MQTT发送消息到树莓派

news 2025/8/18 6:31:50

一、场景描述

Arduino Uno R4和树莓派4B+均配备WiFi通讯模块，当连接到同一网络时，两者可以通过MQTT协议进行无线通讯。

如图所示，本教程介绍Arduino Uno R4（简称Ar）通过MQTT发送消息到Raspberry Pi 4B+（简称Pi）的实现方案。

二、准备工作

1、无线网络：互联网或局域网

2、计算机：用于配置Ar和Pi，与Ar和Pi连接到同一网络中

3、Ar：主板与数据线

4、Pi：主板与电源线

本教程中的Pi运行无桌面版本。如果对系统安装、网络配置、SSH连接、网络加速等不熟悉，可先阅读以下两个教程。

树莓派4/5：在无显示器（无屏幕）下的Lite系统安装与远程控制_raspberry pi os lite-CSDN博客

树莓派4/5：设置apt、pip、conda首选清华镜像源_树莓派清华源-CSDN博客

三、设置Pi

在使用Pi作为接收端之前，需要安装并启用MQTT服务。

MQTT Broker（MQTT 代理） 是 MQTT（Message Queuing Telemetry Transport，消息队列遥测传输）协议中的核心组件，负责接收、处理和转发消息。它类似于邮局或交换机，协调客户端（Publisher 发布者和 Subscriber 订阅者）之间的通信。

Pi要成为MQTT服务器，需要安装mosquitto和paho-mqtt库。

1、安装和配置mosquitto

（1）安装mosquitto

sudo apt update
sudo apt install mosquitto mosquitto-clients -y
sudo systemctl enable mosquitto
sudo systemctl start mosquitto

（2）创建用户名和密码

# mqttuser可以自定义，指的是mqtt的用户名，例如yu
sudo mosquitto_passwd -c /etc/mosquitto/passwd mqttuser

（3）配置mosquitto

首先，打开配置文件。

sudo nano /etc/mosquitto/mosquitto.conf

在所打开的conf文件中，添加#Add后面的三行内容。

pid_file /run/mosquitto/mosquitto.pidpersistence true
persistence_location /var/lib/mosquitto/log_dest file /var/log/mosquitto/mosquitto.log# Add
listener 1883 0.0.0.0
allow_anonymous false
password_file /etc/mosquitto/passwd

编辑完成后，依次按Ctrl+X，按Y，按Enter。

（4）重启mosquitto

sudo systemctl restart mosquitto

（5）确认mosquitto

sudo systemctl status mosquitto

如果显示active (running)，说明mosquitto（MQTT服务）已开启。

2、安装paho-mqtt

paho-mqtt是 Eclipse Foundation 旗下的开源 MQTT 客户端项目，提供多种编程语言的 MQTT 实现，适用于 IoT（物联网）、嵌入式系统和服务器应用。

建议使用miniforge创建虚拟环境。

假设已经安装miniforge，安装paho-mqtt示例如下。

# 创建mqtt虚拟环境
mamba create -n mqtt python=3.9# 激活mqtt虚拟环境
conda activate mqtt# 安装paho-mqtt库
pip install paho-mqtt

3、编写接收端程序

Pi作为接收端，需要指定自身的IP地址、用户名和密码，即BROKER、USERNAME、PASSWORD，TOPIC不建议修改。

import paho.mqtt.client as mqtt# raspberrypi IP address
BROKER = "192.168.X.XXX"
PORT = 1883
# username
USERNAME = "pi"
# password
PASSWORD = "raspberry"
# topic
TOPIC = "arduino/simple"def on_connect(client, userdata, flags, rc):if rc == 0:print("Connected to MQTT Broker!")client.subscribe(TOPIC)else:print("Failed to connect, return code %d\n", rc)def on_message(client, userdata, msg):print(f"Received message: {msg.payload.decode()} from topic: {msg.topic}")client = mqtt.Client()
client.username_pw_set(USERNAME, PASSWORD)
client.on_connect = on_connect
client.on_message = on_messageclient.connect(BROKER, PORT, keepalive=60)
client.loop_forever()

四、设置Ar

Ar只需要编写程序即可。

1、编写发送端程序

注意，ssid[]、pass[]、broker、mqttClient.setUsernamePassword等参数需要自定义。

#include <ArduinoMqttClient.h>
#include <WiFiS3.h># WiFi账号密码
char ssid[] = "WiFi";    
char pass[] = "raspberrypi"; WiFiClient wifiClient;
MqttClient mqttClient(wifiClient);# 树莓派IP地址
const char broker[] = "192.168.X.XXX";
int port = 1883;
const char topic[] = "arduino/simple";const long interval = 1000;
unsigned long previousMillis = 0;
int count = 0;void setup() {// 初始化串口通信Serial.begin(9600);Serial.println("=== Serial communication started ===");// 等待串口连接（仅对有USB CDC功能的板卡有效）unsigned long startWait = millis();while (!Serial && (millis() - startWait) < 5000) {; // 等待最多5秒}Serial.println("Attempting to connect to WiFi...");Serial.print("SSID: ");Serial.println(ssid);int wifiStatus = WL_IDLE_STATUS;while (wifiStatus != WL_CONNECTED) {wifiStatus = WiFi.begin(ssid, pass);Serial.print("WiFi connection attempt. Status: ");Serial.println(wifiStatus);delay(5000);}Serial.println("\nConnected to WiFi!");Serial.print("IP Address: ");Serial.println(WiFi.localIP());Serial.print("Signal Strength (RSSI): ");Serial.print(WiFi.RSSI());Serial.println(" dBm");// 设置MQTT凭证，MQTT服务器的账号密码mqttClient.setUsernamePassword("pi", "raspberry");Serial.println("Attempting to connect to MQTT broker...");Serial.print("Broker: ");Serial.print(broker);Serial.print(":");Serial.println(port);while (!mqttClient.connect(broker, port)) {Serial.print("MQTT connection failed! Error code = ");Serial.println(mqttClient.connectError());delay(5000);}Serial.println("Connected to MQTT broker!");Serial.println("Setup complete. Starting main loop...");
}void loop() {// 必须定期调用poll()来保持连接活跃mqttClient.poll();unsigned long currentMillis = millis();if (currentMillis - previousMillis >= interval) {previousMillis = currentMillis;String message = "hello " + String(count);Serial.print("Preparing to send message: ");Serial.println(message);// 发送MQTT消息mqttClient.beginMessage(topic);mqttClient.print(message);mqttClient.endMessage();Serial.print("Message sent at ");Serial.print(currentMillis);Serial.print(" ms. Count: ");Serial.println(count);count++;}// 添加一个小延迟以避免过于频繁的循环delay(10);
}