WOKWI ESP32 connects to the free public MQTT broker 2

 WOKWI ESP32 connects to the free public MQTT broker (2)

方塊圖

WOKWI程式

#include <ArduinoMqttClient.h>

#include <WiFi.h>

//#define LED 13      //定義LED接腳

int LED = 13;

char ssid[]="Wokwi-GUEST";

char pass[]="";

WiFiClient wifiClient;

MqttClient mqttClient(wifiClient);

//const char broker[] = "test.mosquitto.org";

const char broker[] = "broker.emqx.io";

int        port     = 1883;

const char *SubTopic1 = "alex9ufo/LED_control";

const char willTopic[] = "alex9ufo/Starting";

//布林代數 LED狀態 是否連上網路ESP32 ready ?

bool ledState = false;

bool atwork = false;

String LEDjson = "";

bool Flash = false;  //true

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

void onMqttMessage(int messageSize) {

  // we received a message, print out the topic and contents

  Serial.print("Received a message with topic '");

  Serial.print(mqttClient.messageTopic());

  String Topic= mqttClient.messageTopic();

  Serial.print("', duplicate = ");

  Serial.print(mqttClient.messageDup() ? "true" : "false");

  Serial.print(", QoS = ");

  Serial.print(mqttClient.messageQoS());

  Serial.print(", retained = ");

  Serial.print(mqttClient.messageRetain() ? "true" : "false");

  Serial.print("', length ");

  Serial.print(messageSize);

  Serial.println(" bytes:");

  String message="";

  // use the Stream interface to print the contents

  while (mqttClient.available()) {

    //Serial.print((char)mqttClient.read());

    message += (char)mqttClient.read();

  }

  Serial.println(message);

  message.trim();

  Topic.trim();

  if (Topic=="alex9ufo/LED_control") {

  if (message == "on") {

    digitalWrite(LED, LOW);  // Turn on the LED

    //ledState = true;  //ledState = ture HIGH

    //設定 各個 旗號

    LEDjson ="ON";

    Flash = false;

    Serial.print("LED =");

    Serial.println(LEDjson);

  }

  if (message == "off" ) {

    digitalWrite(LED, HIGH); // Turn off the LED

    //ledState = false; //ledState = false LOW

    LEDjson ="OFF";

    Flash = false;

    Serial.print("LED =");

    Serial.println(LEDjson);

  }

 

  if (message == "flash" ) {

    digitalWrite(LED, HIGH); // Turn off the LED

    Flash = true;

    LEDjson ="FLASH";

    Serial.print("LED =");

    Serial.println(LEDjson);      

  }

    Serial.println();

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

  }  

}

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

//副程式  setup wifi

void setup_wifi() {

  delay(10);

  // We start by connecting to a WiFi network

  Serial.println();

  Serial.print("Connecting to ");

  Serial.println(ssid);     //print ssid

  WiFi.begin(ssid, pass);  //初始化WiFi 函式庫並回傳目前的網路狀態

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

    delay(500);

    Serial.print(".");

  }   //假設 wifi 未連接 show ………

  Serial.println("");

  Serial.println("WiFi connected");

  Serial.println("IP address: ");

  Serial.println(WiFi.localIP());

}  

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

//判斷 旗號Flash , Timer 是否為真

void LED_Message() {

  //判斷 旗號 Flash / timer  是否為真 ? 閃爍 定時

 

  if (Flash){

    digitalWrite(LED, !digitalRead(LED));

    delay(500);

    if (digitalRead(LED))

      ledState = true;

    else

      ledState = false;

  } //(Flash)

}

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

void setup() {

  pinMode(LED, OUTPUT);

  digitalWrite(LED, HIGH);  // Turn off the LED initially

  //Initialize serial and wait for port to open:

  Serial.begin(115200);   // Initialize serial communications with the PC

  while (!Serial);    // Do nothing if no serial port is opened (added for Arduinos based on ATMEGA32U4)

 

  setup_wifi();

  Serial.println("You're connected to the network");

  Serial.println();

 

  String willPayload = "ESP32 Start working....!";

  bool willRetain = true;

  int willQos = 1;

  mqttClient.beginWill(willTopic, willPayload.length(), willRetain, willQos);

  mqttClient.print(willPayload);

  mqttClient.endWill();

  Serial.print("Attempting to connect to the MQTT broker: ");

  Serial.println(broker);

  if (!mqttClient.connect(broker, port)) {

    Serial.print("MQTT connection failed! Error code = ");

    Serial.println(mqttClient.connectError());

    while (1);

  }

  Serial.println("You're connected to the MQTT broker!");

  Serial.println();

  // set the message receive callback

  mqttClient.onMessage(onMqttMessage);

  Serial.print("Subscribing to topic: ");

  Serial.println(SubTopic1);

 

  // subscribe to a topic

  // the second parameter sets the QoS of the subscription,

  // the the library supports subscribing at QoS 0, 1, or 2

  int subscribeQos = 1;

  mqttClient.subscribe(SubTopic1, subscribeQos);

  Serial.println();

  delay(4);       // Optional delay. Some board do need more time after init to be ready, see Readme

}

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

void loop() {

  // call poll() regularly to allow the library to receive MQTT messages and

  // send MQTT keep alives which avoids being disconnected by the broker

  mqttClient.poll();

  LED_Message();

 

}

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

MQTTx 設定

https://www.youtube.com/watch?v=LHUztKEBiu0

https://www.youtube.com/watch?v=f8mu-UMVtqQ