MQTT server is up and running on raspberry pi,
when I do a code to send data through mqtt on esp32 by addressing the raspberry pi by its IP address, its working fine, but when I put the DNS of raspberry pi which is "rpi.local", the same code doesn't work and gives the error
Serial terminal output:- Attempting MQTT connection...failed, rc=-2 try again in 5 seconds)
DNS on pi is working because the same code posted below is working on esp8266, means DNS resolving is working on esp8266 but not on esp32. Any help is highly appreciated.
Thank you
Code: Select all
#include <WiFi.h>
#include <PubSubClient.h>
// Update these with values suitable for your network.
const char* ssid = "Robotics_Lab";
const char* password = "vidya123";
const char* mqtt_server = "rpi.local"; // the newly created DNS by me
WiFiClient espClient;
PubSubClient client(espClient);
long lastMsg = 0;
char msg[50];
int value = 0;
int relay = 15;
/*************************************************************************/
#define ANALOG_PIN_0 36
int currentPin = 36; //Assign CT input to pin 1
double kilos = 0;
int peakPower = 0;
int mVperAmp = 185;
double Voltage = 0;
double VRMS = 0;
double AmpsRMS = 0;
/****************************************************************************/
unsigned long currentMillis;
unsigned long previousMillis = 0;
unsigned long interval = 2000;
void setup_wifi() {
delay(10);
// We start by connecting to a WiFi network
Serial.println();
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.mode(WIFI_STA);
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("Message arrived [");
Serial.print(topic);
Serial.print("] ");
for (int i = 0; i < length; i++) {
Serial.print((char)payload[i]);
}
Serial.println();
// Switch on the LED if an 1 was received as first character
if ((char)payload[0] == '1') {
digitalWrite(2, HIGH); // Turn the LED on (Note that LOW is the voltage level
// but actually the LED is on; this is because
// it is active low on the ESP-01)
digitalWrite(relay, HIGH);
Serial.println("relay1 on");
} else {
digitalWrite(2, LOW); // Turn the LED off by making the voltage HIGH
digitalWrite(relay, LOW);
Serial.println("relay1 off");
}
if ((char)payload[1] == '1') {
//digitalWrite(2, HIGH); // Turn the LED on (Note that LOW is the voltage level
// but actually the LED is on; this is because
// it is active low on the ESP-01)
//digitalWrite(relay, HIGH);
Serial.println("relay2 on");
} else {
//digitalWrite(2, LOW); // Turn the LED off by making the voltage HIGH
//digitalWrite(relay, LOW);
Serial.println("relay2 off");
}
if ((char)payload[2] == '1') {
digitalWrite(2, HIGH); // Turn the LED on (Note that LOW is the voltage level
// but actually the LED is on; this is because
// it is active low on the ESP-01)
//digitalWrite(relay, HIGH);
Serial.println("relay3 on");
} else {
digitalWrite(2, LOW); // Turn the LED off by making the voltage HIGH
//digitalWrite(relay, LOW);
Serial.println("relay3 off");
}
if ((char)payload[3] == '1') {
digitalWrite(2, HIGH); // Turn the LED on (Note that LOW is the voltage level
// but actually the LED is on; this is because
// it is active low on the ESP-01)
//digitalWrite(relay, HIGH);
Serial.println("relay4 on");
} else {
digitalWrite(2, LOW); // Turn the LED off by making the voltage HIGH
//digitalWrite(relay, LOW);
Serial.println("relay4 off");
}
/*
if ((char)payload[3] == '1') {
digitalWrite(2, LOW); // Turn the LED on (Note that LOW is the voltage level
// but actually the LED is on; this is because
// it is active low on the ESP-01)
//digitalWrite(relay, HIGH);
Serial.println("relay4");
} else {
digitalWrite(2, HIGH); // Turn the LED off by making the voltage HIGH
//digitalWrite(relay, LOW);
}*/
}
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("power", "hello world");
// ... and resubscribe
client.subscribe("ESP32-1");
} 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() {
pinMode(currentPin, INPUT); // Initialize the 2 pin as an output
Serial.begin(115200);
setup_wifi();
client.setServer(mqtt_server, 1883);
client.setCallback(callback);
}
float getVPP()
{
float result;
int readValue; //value read from the sensor
int maxValue = 0; // store max value here
int minValue = 4096; // store min value here
uint32_t start_time = millis();
while ((millis() - start_time) < 1000) //sample for 1 Sec
{
readValue = analogRead(ANALOG_PIN_0);
// see if you have a new maxValue
if (readValue > maxValue)
{
/*record the maximum sensor value*/
maxValue = readValue;
}
if (readValue < minValue)
{
/*record the maximum sensor value*/
minValue = readValue;
}
}
// Subtract min from max
result = ((maxValue - minValue) * 3.3) / 4096.0;
return result;
}
void loop() {
if (!client.connected()) {
reconnect();
}
client.loop();
long now = millis();
/*
if (now - lastMsg > 2000) {
lastMsg = now;
value=!value;
// Serial.println(value);
if(value == 1)
snprintf (msg, 50, "%s","ON");
if(value == 0)
snprintf (msg, 50, "%s","OFF");
Serial.print("Publish message: ");
Serial.println(msg);
client.publish("state",msg);
delay(2000);
}*/
/**************************************************************/
/*******************************************************************************/
Voltage = getVPP();
VRMS = (Voltage / 2.0) * 0.707;
AmpsRMS = (VRMS * 1000) / mVperAmp;
AmpsRMS = AmpsRMS - 0.13;
if (AmpsRMS < 0.35) AmpsRMS = 0;
//Serial.print(AmpsRMS);
//Serial.println(" Amps RMS");
//Serial.println(" *************************************************");
int RMSPower = 220 * AmpsRMS; //Calculates RMS Power Assuming Voltage 220VAC, change to 110VAC accordingly
if (RMSPower > peakPower)
{
peakPower = RMSPower;
}
kilos = kilos + (RMSPower * (2.05 / 60 / 60 / 1000)); //Calculate kilowatt hours used
/**********************************************************/
Serial.print("RMS Current = ");
Serial.print(AmpsRMS);
Serial.println("A");
Serial.print("RMSPower = ");
Serial.print(RMSPower);
Serial.println("W");
Serial.print("Total Units = ");
Serial.print(kilos);
Serial.println("kWh");
/*********************************************************************/
Serial.println("here");
currentMillis = millis();
if (currentMillis - previousMillis > interval)
{
previousMillis = currentMillis;
//lastMsg = now;
// Serial.println(value);
sprintf (msg, "%f", kilos);
Serial.print("Publish message: ");
Serial.println(msg);
client.publish("state", msg);
delay(2000);
}
// kilos = 6.9;
}