一、前言

1、能够使用Arduino的软串口控制Esp8266接入网络，可以看看我的前两个博客。

3、需要的库文件

WiFiEsp库是一个Arduino的封装好AT指令的WiFi操作库，可以使用Arduino的软串口操作

PubSubClient是一个用于Esp8266发布/订阅MQTT消息的库。

链接：https://pan.baidu.com/s/1mAaIbO3-SzVaN-jaaFwVbw 
提取码：ol2p

4、修改Esp8266串口波特率为9600

使用AT指令输入AT+UART_DEF=9600,8,1,0,0，如何使用AT指令请看Arduino Esp8266开发（一）AT指令调试

5、参考的文章网址

二、Arduino代码

#include "DHT.h" #include <WiFiEspClient.h> #include <WiFiEsp.h> #include <WiFiEspUdp.h> #include <PubSubClient.h> #include "SoftwareSerial.h" #define WIFI_AP "xxxx" //你家Wifi名称 #define WIFI_PASSWORD "****" //密码 // DHT #define DHTPIN 10 //DHT引脚 #define DHTTYPE DHT11 // 初始化DHT11传感器 DHT dht(DHTPIN, DHTTYPE); char MqttServer[] = "1.11.111.0"; //MQTT服务器的IP地址（阿里云公网IP） WiFiEspClient espClient; // 初始化以太网客户端对象 -- WiFiEspClient.h PubSubClient client(espClient); // 初始化MQTT库PubSubClient.h的对象 SoftwareSerial mySerial(2, 3); // RX, TX，声明一个软串口 int status = WL_IDLE_STATUS; unsigned long lastSend; void setup() { Serial.begin(9600); dht.begin(); InitWiFi(); // 连接WiFi client.setServer( MqttServer, 1883 ); // 连接WiFi之后，连接MQTT服务器 lastSend = 0; } void loop() { status = WiFi.status(); if ( status != WL_CONNECTED) { while ( status != WL_CONNECTED) { Serial.print("[loop()]Attempting to connect to WPA SSID: "); Serial.println(WIFI_AP); // 连接WiFi热点 status = WiFi.begin(WIFI_AP, WIFI_PASSWORD); delay(500); } Serial.println("[loop()]Connected to AP"); } if ( !client.connected() ) { reconnect(); } if ( millis() - lastSend > 1000 ) { // 用于定时1秒钟发送一次数据 getAndSendTemperatureAndHumidityData(); // 获取温湿度数据发送到MQTT服务器上去 lastSend = millis(); } client.loop(); } /*
 * 读取温湿度数据，然后发送到MQTT服务器上去
 */ void getAndSendTemperatureAndHumidityData() { Serial.println("Collecting temperature data."); // 大概250ms读取一次 float h = dht.readHumidity(); float t = dht.readTemperature(); // 查看是否读取温湿度失败的 if (isnan(h) || isnan(t)) { Serial.println("Failed to read from DHT sensor!"); return; } Serial.print("Humidity: "); Serial.print(h); Serial.print(" %\t"); Serial.print("Temperature: "); Serial.print(t); Serial.print(" *C "); String temperature = String(t); String humidity = String(h); Serial.print( "Sending temperature and humidity : [" ); Serial.print( temperature ); Serial.print( "," ); Serial.print( humidity ); Serial.print( "]   -> " ); // 构建一个 JSON 格式的payload的字符串 String payload = "{"; payload += "\"temperature\":"; payload += temperature; payload += ","; payload += "\"humidity\":"; payload += humidity; payload += "}"; char attributes[100]; payload.toCharArray( attributes, 100 ); client.publish( "DHT11", attributes ); //发布名字为“DHT11”的主题 Serial.print("[publish]-->>"); Serial.println( attributes ); } /**
 *Wifi连接初始化
 */ void InitWiFi() { // 初始化软串口，软串口连接ESP模块 mySerial.begin(9600); // 初始化ESP模块 WiFi.init(&mySerial); // 检测WiFi模块在不在，宏定义：WL_NO_SHIELD = 255,WL_IDLE_STATUS = 0, if (WiFi.status() == WL_NO_SHIELD) { Serial.println("WiFi shield not present"); while (true); } Serial.println("[InitWiFi]Connecting to AP ..."); // 尝试连接WiFi网络 while ( status != WL_CONNECTED) { Serial.print("[InitWiFi]Attempting to connect to WPA SSID: "); Serial.println(WIFI_AP); status = WiFi.begin(WIFI_AP, WIFI_PASSWORD); delay(500); } Serial.println("[InitWiFi]Connected to AP"); } /**
 * MQTT客户端断线重连函数
 */ void reconnect() { // 一直循环直到连接上MQTT服务器 while (!client.connected()) { Serial.print("[reconnect]Connecting to MQTT Server ..."); // 尝试连接connect是个重载函数 (clientId, username, password) if ( client.connect("mqttx_f4bb1f54", "zky", "135") ) { //设置客户端ID（自定义），用户名，密码 Serial.println( "[DONE]" ); } else { Serial.print( "[FAILED] [ mqtt connect error code = " ); Serial.print( client.state() ); Serial.println( " : retrying in 5 seconds]" );// Wait 5 seconds before retrying delay( 5000 ); } } }