环境依赖

本项目在Windows环境下开发，所使用的软件和三方库如下

• Arduino IDE 1.8.16 (下载地址)
• DHT-sensor-library(地址 移动至 Arduino/libraries) DHT传感器驱动
• Adafruit_Sensor(地址 移动至 Arduino/libraries) DHT传感器依赖
• PubSubClient(工具=>管理库 下载) MQTT库
• ArduinoJson(工具=>管理库 下载) JSON转换工具

注册产品

本项目使用的是涂鸦智能平台提供的MQTT服务

创建产品

选择产品类型，这里以温湿度传感器为例

选择设备接入

完善产品信息

填写功能定义

设备开发界面免费领取2个授权凭证

保存好DeviceID和DeviceSecret，编写程序时填写

编写程序

引脚定义

#include "DHT.h"
#include "WiFi.h"
// #include "WiFiClientSecure.h"
#include "PubSubClient.h"
#include "ArduinoJson.h"

GPIO///
#define DHTPIN 15
#define ADCPIN 32
#define DHTTYPE DHT11   // DHT 11
#define LIGHTPIN 2
#define FANPIN 13
GPIO///

配置WiFi

WIFI///
#define WIFI_SSID "TJ***"       //wifi名
#define WIFI_PASSWD "tjark***" //wifi密码
WIFI///

配置MQTT

这里的用户名密码参考tuyaMQTT开放协议

MQTT///
#define mqttServer "m1.tuyacn.com"
#define mqttPort 1883
#define ClientId "tuyalink_6c7e8f5a8fd2eee79ea***"
#define User "6c7e8f5a8fd2eee79ea***|signMethod=hmacSha256,timestamp=1639372190,securemode=1,accessType=1"
#define Pass "1ccfff232bafe35be78d0eed7e952f7c37cde39b148c8c2f672fedd85875c***"
#define TOPIC "tylink/6c7e8f5a8fd2eee79ea***/thing/property/set"
MQTT///

实例化

WiFiClient espClient;               //创建网络连接客户端
PubSubClient client(espClient);     //创建mqtt客户端
DHT dht(DHTPIN, DHTTYPE);           //DHT实例化

连接WiFi

//连接WIFI相关函数
void setupWifi()
{
  delay(10);
  Serial.println("Connecting WIFI");
  WiFi.begin(WIFI_SSID, WIFI_PASSWD);
  while (!WiFi.isConnected())
  {
    Serial.print(".");
    delay(500);
  }
  Serial.println("OK");
  Serial.println("Wifi connected successfully!");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

连接MQTT

//连接mqtt
void setupMQTT()
{
  client.setServer(mqttServer, mqttPort);
  client.setCallback(callback); 
  while (!client.connected())
  {
    Serial.println("Connecting MQTT");
    if(client.connect(ClientId,User,Pass))
    {
      Serial.println("MQTT connected successfully!");
      client.subscribe(TOPIC);
    }
    else
    {
      Serial.print("Failed with state ");
      Serial.println(client.state());
      delay(2000);
    }
  }
}

编写MQTT回调函数

// MQTT回调函数
void callback(char * topic,byte * payload,unsigned int length){
  DynamicJsonDocument doc(512);
  char charbuffer[512];
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.println("]");
  int i = 0;
  for(;i<length;i++){
    charbuffer[i] = (char)payload[i];
  }
  charbuffer[i] = '';
  DeserializationError error = deserializeJson(doc,charbuffer);

  if(error){
    Serial.print(F("deserializeJson() failed: "));
    Serial.println(error.f_str());
    return;
  }
  bool lightOn = doc["data"]["light_switch"];
  bool dehumiOn = doc["data"]["dehumi_switch"];
  if (lightOn){
    digitalWrite(LIGHTPIN,HIGH);
  }
  else{
    digitalWrite(LIGHTPIN,LOW);
  }
  if (dehumiOn){
    digitalWrite(FANPIN,HIGH);
  }
  else{
    digitalWrite(FANPIN,LOW);
  }
}

初始化

void setup() {
  // put your setup code here, to run once:
  pinMode(LIGHTPIN,OUTPUT);
  Serial.begin(115200);
  setupWifi();
  setupMQTT();
  dht.begin();
}

主函数

void loop() {
  // put your main code here, to run repeatedly:
  // Wait a few seconds between measurements.
  delay(5000);
  // Read humidity data
  int h = dht.readHumidity();
  // Read temperature as Celsius (the default)
  int t = dht.readTemperature();
  
  // Check if any reads failed and exit early (to try again).
  if (isnan(h) || isnan(t)) {
    Serial.println(F("Failed to read from DHT sensor!"));
    return;
  }

  // Read illumination data
  float l = analogRead(ADCPIN);
  int percent = 100 - l / 4096.0 * 100.0;

  // 串口打印
  Serial.print(F("Humidity: "));
  Serial.print(h);
  Serial.print(F("%  Temperature: "));
  Serial.print(t);
  Serial.print(F("C "));
  Serial.print(F("illumination: "));
  Serial.print(percent);
  Serial.println(F("% "));

  // 封装json
  DynamicJsonDocument doc(512);
  DynamicJsonDocument jsdata(256);
  DynamicJsonDocument tempdata(32);
  DynamicJsonDocument humidata(32);
  DynamicJsonDocument illudata(32);

  tempdata["value"] = t;
  tempdata["time"] = 1639454915;
  humidata["value"] = h;
  humidata["time"] = 1639454915;
  illudata["value"] = percent;
  illudata["time"] = 1639454915;
  jsdata["temp_current"] = tempdata;
  jsdata["humidity_current"] = humidata;
  jsdata["illumi_current"] = illudata;
  doc["msgId"] = "45lkj3551234001";
  doc["time"] = 1639454915;
  doc["data"] = jsdata;

  String str;
  serializeJson(doc, str);
//  Serial.println(str);

  // Sending to MQTT
  char *p = (char *)str.c_str();
  if(client.publish("tylink/6c7e8f5a8fd2eee79ea***/thing/property/report",p) == true)
  {
    Serial.println("Success sending message.");
  }
  else
  {
    Serial.println("Failed sending message.");
  }

  client.loop();
}

调试验证

程序烧写进esp32后，可在在线调试功能界面调试，查看传感器数据，验证功能