LED TEMPERATURE HUMIDITY APK Ver2.0 (ESP32. MQTT. Broker. Publish. Subscribe .MIT APP Inventor)

 LED TEMPERATURE HUMIDITY APK Ver2.0  (ESP32. MQTT. Broker. Publish. Subscribe .MIT APP Inventor)

參考來源 https://github.com/HighVoltages/Mqtt-in-Android-app---mit-app-inventor

MIT INVENTOR 程式

https://drive.google.com/file/d/1y1DJz7S6jgSd-jSFo_LUMlmXKUTHnkvP/view?usp=sharing

WOKWI程式

#include <WiFi.h>

#include <PubSubClient.h>

#include <ArduinoJson.h>

#include <DHTesp.h>

//

const int DHTPIN = 15;

const int LED = 13;

DHTesp dhtSensor;

uint32_t delayMS;

const char* ssid = "Wokwi-GUEST";

const char* password = "";

const char *mqtt_broker = "broker.hivemq.com";

const int mqtt_port = 1883;

//MQTT Credentials

const char* topic = "alex9ufo/Tempdata"; //publish topic

//parameters for using non-blocking delay

unsigned long previousMillis = 0;

const long interval = 5000;

String msgStr = "";      // MQTT message buffer

float temp, hum;

//setting up wifi and mqtt client

WiFiClient espClient;

PubSubClient client(espClient);

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

void setup_wifi() {

  delay(10);

  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 reconnect() {

  // Loop until we're reconnected

  while (!client.connected()) {

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

    // Create a random client ID

    String clientId = "ESP32Client-";

    clientId += String(random(0xffff), HEX);

    // Attempt to connect

    if (client.connect(clientId.c_str())) {

      Serial.println("Connected");

      // Once connected, publish an announcement...

      //client.publish("alex9ufo/esp32", "iotfrontier");

      // ... and resubscribe

      client.subscribe("alex9ufo/lights");

    } else {

      Serial.print("failed, rc=");

      Serial.print(client.state());

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

      // Wait 5 seconds before retrying

      delay(5000);

    }

  }

}

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

//subscribe call back

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

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

  Serial.println(topic);

  Serial.print("Message:");

  String data = "";

  for (int i = 0; i < length; i++) {

    Serial.print((char)payload[i]);

    data += (char)payload[i];

  }

  Serial.println();

  Serial.print("Message size :");

  Serial.println(length);

  Serial.println();

  Serial.println("-----------------------");

  Serial.println(data);

  if(data=="ON"){

    Serial.println("LED =on");

    digitalWrite(LED,LOW );

  }

  else{

    Serial.println("LED =off");

    digitalWrite(LED,HIGH );

  }

}

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

void setup() {

  Serial.begin(115200);

  // Initialize device.

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

  pinMode(LED, OUTPUT);

  digitalWrite(LED, LOW);

  setup_wifi();

  client.setServer(mqtt_broker , 1883); //setting MQTT server

  client.setCallback(callback); //defining function which will be called when message is recieved.

}

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

void loop() {

  if (!client.connected()) { //if client is not connected

    reconnect(); //try to reconnect

  }

  client.loop();

  unsigned long currentMillis = millis(); //read current time

  if (currentMillis - previousMillis >= interval) { //if current time - last time > 5 sec

    previousMillis = currentMillis;

    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);

    msgStr = String(temp) +","+String(hum);

    byte arrSize = msgStr.length() + 1;

    char msg[arrSize];

    Serial.print("PUBLISH DATA:");

    Serial.println(msgStr);

    msgStr.toCharArray(msg, arrSize);

    client.publish(topic, msg);

    msgStr = "";

    delay(50);

  }

}

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