Esp8266

FAQ's
112

I have the Arduino code to use MQTT here Using Node-RED as a Local Fallback Server however it’s not a copy and paste. Try the code below and see if it works. I did not test it.

Change settings on the line “if (client.connect(clientID, username, password)) {” to match your MQTT info.

#include <PubSubClient.h>
#include <ESP8266WiFi.h>

const char* ssid = "SSID";
const char* password = "PASSWORD";
const char* mqtt_server = "mqtt.mydevices.com";

WiFiClient espClient;
PubSubClient client(espClient);
long lastMsg = 0;
char msg[50];
int value = 0;

void setup() {
  int timeoutcounter = 0;
  
  Serial.begin(9600);
  WiFi.begin(ssid, password);

  Serial.println();
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);
  
  while (WiFi.status() != WL_CONNECTED) {
    timeoutcounter++;
    delay(500);
    Serial.print(".");
    if (timeoutcounter >= 30){
      Serial.println("Failed to connect to wireless - sleeping for 5 minutes");
      delay(100);
      ESP.deepSleep(300000000, WAKE_RF_DEFAULT);
      delay(100);
    }
  }
  
  Serial.println("");
  Serial.println("WiFi connected");

  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
}

void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Attempt to connect
    if (client.connect(clientID, username, password)) {
      Serial.println("connected");
      client.subscribe("CayenneInput");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Sleep for 5 minutes before retrying
      Serial.println("Failed to connect to MQTT server - sleeping for 5 minutes");
      delay(100);
      ESP.deepSleep(300000000, WAKE_RF_DEFAULT);
      delay(100);
    }
  }
}

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();
}

void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();

  float t = 20.2;
  float h = 30.3;
  float hif = 40.4;
  
  String mqtt_message = "temp,f=" + String(t) + ",channel=10";
  mqtt_message.toCharArray(msg, 50);

  Serial.print("Publish message: ");
  Serial.println(msg);
  client.publish("arduino_1_data", msg, true);

  mqtt_message = "rel_hum,rel_hum=" + String(h) + ",channel=11";
  mqtt_message.toCharArray(msg, 50);

  Serial.print("Publish message: ");
  Serial.println(msg);
  client.publish("arduino_1_data", msg, true);

  mqtt_message = "temp,f=" + String(hif) + ",channel=12";
  mqtt_message.toCharArray(msg, 50);

  Serial.print("Publish message: ");
  Serial.println(msg);
  client.publish("arduino_1_data", msg, true);
  delay(5000);
}
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