WOKWI Servo & MQTT

 WOKWI　Servo & MQTT

#include <WiFi.h>

#include <PubSubClient.h>

#include <ESP32Servo.h>

const int servoPin = 18;

// Update these with values suitable for your network.

const char* ssid =  "Wokwi-GUEST";   // your network SSID (name)

const char* password = "";   // your network password

//const char* mqtt_server = "broker.mqttdashboard.com";// choose your mqtt server

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

Servo servo;// create servo object to control a servo

WiFiClient espClient;

PubSubClient client(espClient);

long lastMsg = 0;

char msg[50];

int value = 0;

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

void setup_wifi() {

   delay(100);

  // We start by connecting to a WiFi network

    Serial.print("Connecting to ");

    Serial.println(ssid);

    WiFi.begin(ssid, password);

    while (WiFi.status() != WL_CONNECTED)

    {

      delay(500);

      Serial.print(".");

    }

  randomSeed(micros());

  Serial.println("");

  Serial.println("WiFi connected");

  Serial.println("IP address: ");

  Serial.println(WiFi.localIP());

}

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

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

{

  Serial.print("Command from MQTT broker is : [");

  Serial.print(topic);

  Serial.print(" Rotation angle is:");

  Serial.print("   ");

  String message="";

  for(int i=0;i<length;i++)

  {

    message += ((char)payload[i]);

    //Serial.print(payload[i]);

  }

  int show= message.toInt();

  if(show <=180 && show >= 0) {  //write()的參數可以是0-180之間，就是你想控制的角度

    servo.write(show);         // tell servo to go to position in variable 'show '

    Serial.print(show);   //print the rotation angle

    Serial.print("]");

    Serial.println();

  }

}//end callback

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

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 you MQTT broker has clientID,username and password

    //please change following line to    if (client.connect(clientId,userName,passWord))

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

    {

      Serial.println("connected");

     //once connected to MQTT broker, subscribe command if any

      client.subscribe("alex9ufo/Command");

    } else {

      Serial.print("failed, rc=");

      Serial.print(client.state());

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

      // Wait 6 seconds before retrying

      delay(6000);

    }

  }

} //end reconnect()

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

void setup() {

  Serial.begin(115200);

  setup_wifi();

  client.setServer(mqtt_server, 1883);

 

  servo.attach(servoPin, 500, 2400);

}

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

void loop() {

  if (!client.connected()) {

    reconnect();

  }

  client.setCallback(callback);

  client.loop();

}

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