ESP32 Forum

Posted: **Fri Jun 18, 2021 6:30 pm**

Hello, I am trying to connect Esp32 to MQTT broker(Raspberry Pi) via Wi-Fi but I am facing issues. I am trying to send "Hello" from Esp32 to MQTT. Upon checking, Esp32 IP Address is: "192.168.0.105", Raspberry Pi IP: "192.169.0.106" and Wi-Fi IP is: "192.168.0.1". I don't know if this is the issue or something else. I am also posting the code below, kindly tell me what am I doing wrong or how can I solve this issue? Thank you.

Code: [Select all] [Expand/Collapse]

[code]
#include <HardwareSerial.h>
#include <PubSubClient.h> //Connect and publish data to the MQTT broker
#include <WiFi.h> //Enables Esp32 to connect to the local network(via WiFi)
#define RXD2 16
#define TXD2 17
//char myRcvChar;
//WiFi
const char* ssid = "Bilal-Asad-310";
const char* wifi_password = "31019309";
//MQTT
const char* mqtt_server = "192.168.0.106";
const char* message_topic = "test/esp32/message";
//const char* bending_topic = "exoskeleton/walking/bending";
//const char* streching_topic = "exoskeleton/walking/streching";
const char* mqtt_username = "pi"; //MQTT username
const char* mqtt_password = "raspberry"; //MQTT password
const char* clientID = "first message";
 
//Initialise the Wifi and MQTT Client objects
WiFiClient wifiClient;
//1883 is the listener port for the broker
PubSubClient client(mqtt_server,1883,wifiClient);
 
 
//Custom function to connect to the MQTT broker via WiFi
void connect_MQTT(){
  Serial.print("Connecting to ");
  Serial.println(ssid);
 
  //Connect to the WiFi
  WiFi.begin(ssid, wifi_password);
 
  //wait until the connection has been confirmed before continuing
  while(WiFi.status()!= WL_CONNECTED){
    delay(500);
    Serial.print(".");
  }
  //Debugging-Output the IP Address of the ESP32
  Serial.println("WiFi connected");
  Serial.println("IP Address");
  Serial.println(WiFi.localIP());
 
  //Connect to MQTT Broker
  //client.connect returns a boolean value to let us know if the connection was successful
  //if the connection is failing, make sure you are using the correct MQTT Username and Password
  if(client.connect(clientID,mqtt_username,mqtt_password)){
    Serial.println("Connected to MQTT Broker");
  }
  else{
    Serial.println("Connection to MQTT Broker failed...");
  }
}
 
void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial2.begin(115200, SERIAL_8N1, RXD2, TXD2);
 //char myRcvchar;
 
 
}
 
void loop() {
  // put your main code here, to run repeatedly:
  connect_MQTT();
  Serial.setTimeout(2000);
  Serial.println("Data Received: ");
  Serial.println(Serial2.readStringUntil('\n'));
 
  const char* message = "Hello";
  Serial.print("Message Received: ");
  Serial.print(message);
  //MQTT can only transmit strings
  String ms = "Mess: "+String((char*)message);
 
  //Publish to MQTT broker
  if(client.publish(message_topic, String(message).c_str())){
    Serial.println("Message sent");
  }
//Again client.publish will return boolean value depending on whether it succeded or not.
//if the message failed to send, try again, as the connection might have broken
else{
  Serial.println("Message failed to send. Reconnecting to MQTT Broker and trying again");
  client.connect(clientID,mqtt_username,mqtt_password);
  delay(10); //This delay ensures that client.publish does not clash with client.connect call
  client.publish(message_topic,String(message).c_str());
}
client.disconnect(); //disconnect from the MQTT broker
delay(1000*60); //print new values every 2 minutes
  
 
}
[/code]

ESP32 Forum

Esp32 and MQTT (Raspberry pi) connection issue

Esp32 and MQTT (Raspberry pi) connection issue