ESP32 MQTT – Publish and Subscribe with Arduino IDE (WOKWI)

ESP32 MQTT – Publish and Subscribe with Arduino IDE (WOKWI)

系統圖

WOKWI電路圖

MQTT Box 

Node-Red

WOKWI程式

#include "WiFi.h";

#include <PubSubClient.h>;

#include <Wire.h>;

#include "DHTesp.h";

// DHT22 Pin

const int DHT_PIN = 15;

// LED Pin

const int ledPin = 4;

// Replace the next variables with your SSID/Password combination

const char* ssid = "Wokwi-GUEST";

const char* password = "";

// Add your MQTT Broker IP address, example:

//const char* mqtt_server = "192.168.1.144";

const char* mqtt_server = "broker.mqttgo.io";

///const char* mqtt_server = "broker.hivemq.com";

//onst char* mqtt_server =  "test.mosquitto.org" ;

WiFiClient espClient;

PubSubClient client(espClient);

DHTesp dhtSensor;

long lastMsg = 0;

//=================================================================

//===================================================================

void setup_wifi() {

  delay(10);

  // We start by connecting to a WiFi network

  Serial.println();

  Serial.print("Connecting to ");

  Serial.println(ssid);

  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {

    delay(500);

    Serial.print(".");

  }

  Serial.println("");

  Serial.println("WiFi connected");

  Serial.println("IP address: ");

  Serial.println(WiFi.localIP());

}

//===================================================================

void callback(char* topic, byte* message, unsigned int length) {

  Serial.print("Message arrived on topic: ");

  Serial.print(topic);

  Serial.print(". Message: ");

  String messageTemp;

 

  for (int i = 0; i < length; i++) {

    Serial.print((char)message[i]);

    messageTemp += (char)message[i];

  }

  Serial.println();

  // Feel free to add more if statements to control more GPIOs with MQTT

  // If a message is received on the topic esp32/output, you check if the message is either "on" or "off".

  // Changes the output state according to the message

  if (String(topic) == "alex9ufo/esp32/output") {

    Serial.print("Changing output to ");

    if(messageTemp == "on"){

      Serial.println("on");

      digitalWrite(ledPin, HIGH);

    }

    else if(messageTemp == "off"){

      Serial.println("off");

      digitalWrite(ledPin, LOW);

    }

  }

}

//===================================================================

void reconnect() {

  // Loop until we're reconnected

  while (!client.connected()) {

    Serial.print("Attempting MQTT connection...");

    // Attempt to connect

    if (client.connect("ESP32Client")) {

      Serial.println("connected");

      // Subscribe

      client.subscribe("alex9ufo/esp32/output");

    } else {

      Serial.print("failed, rc=");

      Serial.print(client.state());

      Serial.println(" try again in 5 seconds");

      // Wait 5 seconds before retrying

      delay(5000);

    }

  }

}

//===================================================================

void setup() {

  Serial.begin(115200);

  pinMode(ledPin, OUTPUT);

  dhtSensor.setup(DHT_PIN, DHTesp::DHT22);

  setup_wifi();

  client.setServer(mqtt_server, 1883);

  client.setCallback(callback);

  client.subscribe("alex9ufo/esp32/output");

 

}

//===================================================================

void loop() {

  if (!client.connected()) {

    reconnect();

  }

  client.loop();

  long now = millis();

  if (now - lastMsg > 5000) {

    lastMsg = now;

    TempAndHumidity  data = dhtSensor.getTempAndHumidity();

    String temp = String(data.temperature, 2);

    Serial.print("Temperature: ");

    Serial.println(temp);

    client.publish("alex9ufo/esp32/temperature", temp.c_str());

   

    String hum = String(data.humidity, 1);

    Serial.print("Humidity: ");

    Serial.println(hum);

    client.publish("alex9ufo/esp32/humidity", hum.c_str());

  }

}

//===================================================================

Node-Red程式

[{"id":"9e58624.7faaba","type":"mqtt out","z":"46d55d9e427d2a08","name":"output","topic":"alex9ufo/esp32/output","qos":"","retain":"","respTopic":"","contentType":"","userProps":"","correl":"","expiry":"","broker":"70940176.2b2d3","x":270,"y":320,"wires":[]},{"id":"abf7079a.653be8","type":"mqtt in","z":"46d55d9e427d2a08","name":"temperature","topic":"alex9ufo/esp32/temperature","qos":"2","datatype":"auto-detect","broker":"70940176.2b2d3","nl":false,"rap":false,"inputs":0,"x":144,"y":227,"wires":[["cc79021b.9a751","21eae8f8.2971b8"]]},{"id":"83cf37cf.c76988","type":"ui_switch","z":"46d55d9e427d2a08","name":"","label":"Output","group":"61285987.c20328","order":0,"width":0,"height":0,"passthru":true,"decouple":"false","topic":"","style":"","onvalue":"on","onvalueType":"str","onicon":"","oncolor":"","offvalue":"off","offvalueType":"str","officon":"","offcolor":"","x":149,"y":320,"wires":[["9e58624.7faaba"]]},{"id":"cc79021b.9a751","type":"debug","z":"46d55d9e427d2a08","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":361,"y":194,"wires":[]},{"id":"4aecba01.78ce64","type":"mqtt in","z":"46d55d9e427d2a08","name":"humidity","topic":"alex9ufo/esp32/humidity","qos":"2","datatype":"auto-detect","broker":"70940176.2b2d3","nl":false,"rap":false,"inputs":0,"x":133,"y":111,"wires":[["22efa7b7.544a28","df37e6b7.64c1c8"]]},{"id":"22efa7b7.544a28","type":"debug","z":"46d55d9e427d2a08","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":350,"y":78,"wires":[]},{"id":"21eae8f8.2971b8","type":"ui_chart","z":"46d55d9e427d2a08","name":"","group":"61285987.c20328","order":0,"width":0,"height":0,"label":"Temperature","chartType":"line","legend":"false","xformat":"HH:mm:ss","interpolate":"linear","nodata":"","dot":false,"ymin":"","ymax":"","removeOlder":1,"removeOlderPoints":"","removeOlderUnit":"3600","cutout":0,"useOneColor":false,"useUTC":false,"colors":["#1f77b4","#aec7e8","#ff7f0e","#2ca02c","#98df8a","#d62728","#ff9896","#9467bd","#c5b0d5"],"outputs":1,"useDifferentColor":false,"className":"","x":361,"y":254,"wires":[[]]},{"id":"df37e6b7.64c1c8","type":"ui_gauge","z":"46d55d9e427d2a08","name":"","group":"61285987.c20328","order":0,"width":0,"height":0,"gtype":"gage","title":"Humidity","label":"%","format":"{{value}}","min":0,"max":"100","colors":["#00b3d9","#0073e6","#001bd7"],"seg1":"33","seg2":"66","className":"","x":340,"y":138,"wires":[]},{"id":"70940176.2b2d3","type":"mqtt-broker","name":"","broker":"broker.mqttgo.io","port":"1883","clientid":"","autoConnect":true,"usetls":false,"protocolVersion":"4","keepalive":"15","cleansession":true,"birthTopic":"","birthQos":"0","birthPayload":"","birthMsg":{},"closeTopic":"","closePayload":"","closeMsg":{},"willTopic":"","willQos":"0","willPayload":"","willMsg":{},"sessionExpiry":""},{"id":"61285987.c20328","type":"ui_group","name":"Main","tab":"e7c46d5e.a1283","order":1,"disp":true,"width":"6","collapse":false},{"id":"e7c46d5e.a1283","type":"ui_tab","name":"Dashboard","icon":"dashboard"}]