alex9ufo 聰明人求知心切: 5月 2024

2024年5月18日星期六

本課程將展示WOKWI ESP32 模擬的基本MQTT協定使用。

WOKWI設定：

#include <WiFi.h>

#include "PubSubClient.h"

// WiFi

char ssid[]="Wokwi-GUEST";

char pass[]="";

// MQTT Broker

const char *mqtt_broker = "broker.mqtt-dashboard.com";//"broker.emqx.io";//Public Broker

const char *mqtt_username = "hivemqtt";

const char *mqtt_password = "public";

const int mqtt_port = 1883;

// App Protcol ---> Port 

const char *topic_publish = "alex9ufo/outTopic";//Topic ESP32 Pusblish

const char *topic_subsrcibe = "alex9ufo/inTopic";//Topic ESp32 Subscribe

WiFiClient hamada;//WIFI Opject

PubSubClient client(hamada);//OOP

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

#define LED 2

bool ledState=false;

unsigned long lastMsg = 0;

#define MSG_BUFFER_SIZE (50)

char msg[MSG_BUFFER_SIZE];

int value = 0;

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(topic_publish, "Hello world.....");

      client.subscribe(topic_subsrcibe);

    } 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(){

   // Setting LED pin as output

    pinMode(LED, OUTPUT);

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

    //Open a serial connection to display program results and establish a connection to the Wi-Fi network.

    // Set software serial baud to 115200;

    Serial.begin(115200);

    // Connecting to a Wi-Fi network

    WiFi.begin(ssid, pass);

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

        delay(500);

        Serial.println("Connecting to WiFi..");

}

        Serial.println("Connected to the Wi-Fi network");

    // Utilize PubSubClient to establish a connection with the MQTT broker.

    //connecting to a mqtt broker

    Serial.println("Before Connect MQTT");

    //Broker Configuration 

    client.setServer(mqtt_broker, mqtt_port);

   while (!client.connected()) {

        String client_id = "esp32-client-";

        client_id =client_id+ String(WiFi.macAddress());

        //consloe.log("x"+"y");//xy

        //ESP32-ID -----> esp32-client-macaddress

        //variable.c_str()--->char [] , String

        Serial.printf("The client %s connects to the public MQTT broker\n", client_id.c_str());

        if (client.connect(client_id.c_str(), mqtt_username, mqtt_password)) {

            Serial.println("Public MQTT broker connected");

        } else {

            Serial.print("failed with state ");

            Serial.print(client.state());//1 , 2 , 5

            delay(2000);

}

}

    Serial.println("After Connect MQTT");

    client.publish(topic_publish, "Hello world.....");

    client.subscribe(topic_subsrcibe);

    client.setCallback(callback);

}

void loop() {

  if (!client.connected()) {

    reconnect();

}

  client.loop();

  unsigned long now = millis();

  if (now - lastMsg > 10000) {

    lastMsg = now;

    ++value;

    snprintf (msg, MSG_BUFFER_SIZE, "hello world #%ld", value);

    Serial.print("Publish message: ");

    Serial.println(msg);

    client.publish(topic_publish, msg);

}

}

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

  printPayload(topic, message, length);  

}

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

  // Printing Received Message

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

  Serial.println(topic);

  String messageTemp;

  for(int i=0; i<length; i+=1) {

    messageTemp += (char)message[i];

}

  if(String(topic) == "alex9ufo/inTopic"){

      Serial.println("alex9ufo/inTopic");

      if(messageTemp=="ON"){

        Serial.println("Led ON");

        digitalWrite(LED,HIGH);

}

      if(messageTemp=="OFF"){

        Serial.println("Led OFF");

        digitalWrite(LED,LOW);

}

}

  Serial.println(messageTemp);

}

{

  "version": 1,

  "author": "Anonymous maker",

  "editor": "wokwi",

  "parts": [

    { "type": "wokwi-esp32-devkit-v1", "id": "esp", "top": -321.7, "left": -168.2, "attrs": {} },

{

      "type": "wokwi-resistor",

      "id": "r1",

      "top": -225.6,

      "left": 37.85,

      "rotate": 90,

      "attrs": { "value": "1000" }

},

{

      "type": "wokwi-led",

      "id": "led1",

      "top": -310.8,

      "left": 32.6,

      "attrs": { "color": "red" }

}

],

  "connections": [

    [ "esp:TX0", "$serialMonitor:RX", "", [] ],

    [ "esp:RX0", "$serialMonitor:TX", "", [] ],

    [ "led1:C", "esp:GND.1", "black", [ "v0" ] ],

    [ "r1:1", "led1:A", "red", [ "h0" ] ],

    [ "esp:D2", "r1:2", "red", [ "h0" ] ]

],

  "dependencies": {}

}

MQTTBox設定：

broker.mqtt-dashboard.com:1883/ws

mqtt / tcp

2024產專班作業2 (純模擬)

1) LED ON,OFF,TIMER,FLASH 模擬　（switch 控制）

2)RFID卡號模擬（buttom 模擬RFID UID(不從ESP32)

3) 使用database需先create建立資料庫

Node-Red 程式

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