使用ESP8266快速开发一个物联网应用

作者: 梅干菜烧饼不加肉 | 来源:发表于2019-04-21 17:22 被阅读69次

    MQTT模板

    一个好的模板将极大的提高编程效率

    传感器 发送数据

    以超声波为例

    #include <ESP8266WiFi.h>
    #include <PubSubClient.h>
    #include <string.h>
    #include <SoftwareSerial.h>
    #include <ArduinoJson.h>
    #include <SPI.h> // Only needed for Arduino 1.6.5 and earlier
    
    //Wifi Configuration
    #define MQTT_VERSION MQTT_VERSION_3_1_1
    const char* WIFI_SSID = "wifi ssid";
    const char* WIFI_PASSWORD = "wifi password";
    const PROGMEM char* MQTT_PUBLISH_TOPIC = "topic";
    const PROGMEM char* MQTT_CLIENT_ID = "client id";
    const PROGMEM char* MQTT_SERVER_IP = "IP";
    const PROGMEM uint16_t MQTT_SERVER_PORT = port;
    const PROGMEM char* MQTT_USER = "user";
    const PROGMEM char* MQTT_PASSWORD = "password";
    
    unsigned int HighLen = 0;
    unsigned int LowLen  = 0;
    unsigned int Len_mm  = 0;
    
    SoftwareSerial us100(D1,D2);//Rx,Tx
    WiFiClient wifiClient;
    PubSubClient client(wifiClient);
    
    void callback(char* p_topic, byte* p_payload, unsigned int p_length) {
    
      // concat the payload into a string
      String payload;
      for (uint8_t i = 0; i < p_length; i++) {
        payload.concat((char)p_payload[i]);
      }
    
    }
    
    void reconnect() {
      // Loop until we're reconnected
      while (!client.connected()) {
        Serial.print("INFO: Attempting MQTT connection...");
        // Attempt to connect
        if (client.connect(MQTT_CLIENT_ID, MQTT_USER, MQTT_PASSWORD)) {
          Serial.println("INFO: connected");
          // Once connected, publish an announcement...
        } else {
          Serial.print("ERROR: failed, rc=");
          Serial.print(client.state());
          Serial.println("DEBUG: try again in 5 seconds");
          // Wait 5 seconds before retrying
          delay(5000);
        }
      }
    }
    void publishData(float dist) {
      // create a JSON object
      // doc : https://github.com/bblanchon/ArduinoJson/wiki/API%20Reference
      StaticJsonBuffer<200> jsonBuffer;
      JsonObject& root = jsonBuffer.createObject();
      // INFO: the data must be converted into a string; a problem occurs when using floats...
      root["distance"] = (String)dist;
      root.prettyPrintTo(Serial);
      /*
         {
            "temperature": "23.20" ,
            "humidity": "43.70"
         }
      */
      char data[200];
      root.printTo(data, root.measureLength() + 1);
      client.publish(MQTT_PUBLISH_TOPIC, data, true);
    }
    
    void setup() {
      // set baudrate as 9600bps.
      us100.begin(9600);
      Serial.begin(9600);
      // init the WiFi connection
      Serial.println();
      Serial.println();
      Serial.print("INFO: Connecting to ");
      WiFi.mode(WIFI_STA);
      Serial.println(WIFI_SSID);
      WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
    
      while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
      }
    
      Serial.println("");
      Serial.println("INFO: WiFi connected");
      Serial.print("INFO: IP address: ");
      Serial.println(WiFi.localIP());
    
      // init the MQTT connection
      client.setServer(MQTT_SERVER_IP, MQTT_SERVER_PORT);
      client.setCallback(callback);
    
    }
    
    void loop() {
      
      if (!client.connected()) {
        reconnect();
      }
        
      us100.flush();     // clear receive buffer of serial port
      us100.write(0X55); // trig US-100 begin to measure the distance
      delay(500);          //delay 500ms to wait result
      
      if(us100.available() >= 2) {                    //when receive 2 bytes 
        HighLen = us100.read();                   //High byte of distance
        LowLen  = us100.read();                   //Low byte of distance
        Len_mm  = HighLen*256 + LowLen;             //Calculate the distance
        
        Serial.print("Distance is: ");   //output the result to serial monitor
        Serial.print(Len_mm);             //output the result to serial monitor
        Serial.println("mm");  
        publishData((float)Len_mm);
      }
    
      delay(500);  
      client.loop();
    }
    

    仅需通过修改头部配置信息 publishData()函数 与 loop循环即可. esp8266将以JSON的数据格式向Broker发送数据

    执行器 接收数据

    以继电器为例

    #include <ESP8266WiFi.h>
    #include <PubSubClient.h>
    #include <ArduinoJson.h>
    #define MQTT_VERSION MQTT_VERSION_3_1_1
    
    //Wifi Configuration
    const char* WIFI_SSID = "wifi ssid";
    const char* WIFI_PASSWORD = "wifi password";
    const PROGMEM char* MQTT_SUBSCRIBE_TOPIC = "relay";
    const PROGMEM char* MQTT_CLIENT_ID = "relay";
    const PROGMEM char* MQTT_SERVER_IP = "mqtt server ip";
    const PROGMEM uint16_t MQTT_SERVER_PORT = 1883;
    const PROGMEM char* MQTT_USER = "mqtt user";
    const PROGMEM char* MQTT_PASSWORD = "mqtt password";
    
    //relay
    
    int relay = D0;
    
    WiFiClient wifiClient;
    PubSubClient client(wifiClient);
    
    void callback(char* p_topic, byte* p_payload, unsigned int p_length) {
    
      String payload;
      
      for (uint8_t i = 0; i < p_length; i++) {
        payload.concat((char)p_payload[i]);
      }
    
      StaticJsonBuffer<200> jsonBuffer;
      // doc : https://github.com/bblanchon/ArduinoJson/wiki/API%20Reference
    
      JsonObject& mBuffer = jsonBuffer.parseObject(payload);
    
      const char* state = mBuffer["state"];
    
      if(state == "on"){
        digitalWrite(relay, HIGH);
      }else if(state == "off"){
        digitalWrite(relay, LOW);
      }
    
    }
    
    void reconnect() {
      // Loop until we're reconnected
      while (!client.connected()) {
        Serial.print("INFO: Attempting MQTT connection...");
        // Attempt to connect
        if (client.connect(MQTT_CLIENT_ID, MQTT_USER, MQTT_PASSWORD)) {
          Serial.println("INFO: connected");
          client.subscribe(MQTT_SUBSCRIBE_TOPIC);
        } else {
          Serial.print("ERROR: failed, rc=");
          Serial.print(client.state());
          Serial.println("DEBUG: try again in 5 seconds");
          // Wait 5 seconds before retrying
          delay(5000);
        }
      }
    }
    
    void setup() {
      Serial.begin(115200);
      Serial.println();
      Serial.println();
      Serial.print("INFO: Connecting to ");
      WiFi.mode(WIFI_STA);
      Serial.println(WIFI_SSID);
      WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
      
      while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
      }
    
      Serial.println("");
      Serial.println("INFO: WiFi connected");
      Serial.print("INFO: IP address: ");
      Serial.println(WiFi.localIP());
    
      // init the MQTT connection
      client.setServer(MQTT_SERVER_IP, MQTT_SERVER_PORT);
      client.setCallback(callback);
    
      pinMode(relay, OUTPUT);
    }
    
    void loop() {
      if (!client.connected()) {
        reconnect();
      }
      client.loop();
    }
    

    仅修改callback()函数即可 通过mBuffer["键"]取值
    上位机数据发送示例

    {"sensor":"gps","time":1351824120,"data":[48.756080,2.302038]}
    

    注意防转义 两边的双引号

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