Arduino R4 MQTT Code Example

gistfile1.txt

// Code with relay and MQTT control

#include <ArduinoMqttClient.h>
#include <WiFiNINA.h>
#include "arduino_secrets.h"

#include <Arduino_JSON.h>
#include <assert.h>

const char input[] = "{\"result\":true,\"count\":42,\"foo\":\"bar\"}";

//const char input[] = "{\"result\":true,\"count\":42,\"foo\":\"bar\"}";

///////please enter your sensitive data in the Secret tab/arduino_secrets.h
char ssid[] = SECRET_SSID;  // your network SSID (name)
char pass[] = SECRET_PASS;  // your network password (use for WPA, or use as key for WEP)

WiFiClient wifiClient;
MqttClient mqttClient(wifiClient);

const char broker[] = "10.35.30.52";
int port = 1883;
const char topic[] = "real_unique_topic";
const char topic2[] = "real_unique_topic_2";
const char topic3[] = "real_unique_topic_3";

// 🟢 NEW: Topic for receiving lamp control commands
const char lampControlTopic[] = "lamp/control";

//set interval for sending messages (milliseconds)
const long interval = 8000;
unsigned long previousMillis = 0;

int count = 0;

const int relayPin = 7;

bool lampState = false;

void setup() {

  //Initialize serial and wait for port to open:
  Serial.begin(9600);



  // attempt to connect to Wifi network:
  Serial.print("Attempting to connect to WPA SSID: ");
  Serial.println(ssid);
  while (WiFi.begin(ssid, pass) != WL_CONNECTED) {
    // failed, retry
    Serial.print(".");
    delay(5000);
  }

  Serial.println("You're connected to the network");
  Serial.println();

  Serial.print("Attempting to connect to the MQTT broker: ");
  Serial.println(broker);

  if (!mqttClient.connect(broker, port)) {
    Serial.print("MQTT connection failed! Error code = ");
    Serial.println(mqttClient.connectError());

    while (1)
      ;
  }

  Serial.println("You're connected to the MQTT broker!");
  Serial.println();
// send message, the Print interface can be used to set the message contents
    mqttClient.beginMessage("Yuxispace");
    char name[] = "IOTLamp,";
    char desc[] = "Lamp connected to the interwebs,";
    char pubs[] = "Switch,";
    char subs[] = "Power";
    // char SendString[] = (name + "," + desc + "," + pubs + "," + subs)
    mqttClient.print(name);
    mqttClient.print(desc);
    mqttClient.print(pubs);
    mqttClient.print(subs);
    mqttClient.endMessage();

  Serial.print("Subscribing to topic: ");
  Serial.println(lampControlTopic);
  mqttClient.subscribe(lampControlTopic);

  mqttClient.onMessage(onMqttMessage);

  pinMode(relayPin, OUTPUT);
  digitalWrite(relayPin, LOW);  // Start with relay OFF
  // Code for Relay ends
}

void onMqttMessage(int messageSize) {
  String message = "";

  // Read the incoming message
  while (mqttClient.available()) {
    message += (char)mqttClient.read();
  }

  Serial.print("Received message on topic: ");
  Serial.println(lampControlTopic);
  Serial.print("Message: ");
  Serial.println(message);

  JSONVar myObject = JSON.parse(message);
  Serial.print(myObject["msg"]);
  String message2 = myObject["msg"];
//  Serial.println(JSON.typeof(myObject));  // prints: object

  lampState = !lampState;
    digitalWrite(relayPin, lampState ? HIGH : LOW);
    Serial.println(lampState ? "💡 Lamp toggled ON" : "🌑 Lamp toggled OFF");

  // Control lamp based on message content
  if (message2 == "ON" || message2 == "on" || message2 == "1") {
    digitalWrite(relayPin, HIGH);
    lampState = true;
    Serial.println("💡 Lamp turned ON");
  } else if (message2 == "OFF" || message2 == "off" || message2 == "0") {
    digitalWrite(relayPin, LOW);
    lampState = false;
    Serial.println("🌑 Lamp turned OFF");
  } else if (message2 == "true" || message2 == "True") {
    lampState = !lampState;
    digitalWrite(relayPin, lampState ? HIGH : LOW);
    Serial.println(lampState ? "💡 Lamp toggled ON" : "🌑 Lamp toggled OFF");
  } else {
    Serial.println("⚠️ Unknown command. Use: ON, OFF, or TOGGLE");
  }
}

void loop() {

  // call poll() regularly to allow the library to send MQTT keep alive which
  // avoids being disconnected by the broker
  mqttClient.poll();

  unsigned long currentMillis = millis();

  if (currentMillis - previousMillis >= interval) {
    // save the last time a message was sent
    previousMillis = currentMillis;

    //record random value from A0, A1 and A2
    int Rvalue = analogRead(A0);
    int Rvalue2 = analogRead(A1);
    int Rvalue3 = analogRead(A2);

    Serial.print("Sending message to topic: ");
    Serial.println(topic);
    Serial.println(Rvalue);

    Serial.print("Sending message to topic: ");
    Serial.println(topic2);
    Serial.println(Rvalue2);

    Serial.print("Sending message to topic: ");
    Serial.println(topic3);
    Serial.println(Rvalue3);

    // send message, the Print interface can be used to set the message contents
    mqttClient.beginMessage(topic);
    mqttClient.print(Rvalue);
    mqttClient.endMessage();

    mqttClient.beginMessage(topic2);
    mqttClient.print(Rvalue2);
    mqttClient.endMessage();

    mqttClient.beginMessage(topic3);
    mqttClient.print(Rvalue3);
    mqttClient.endMessage();

    Serial.println();
  }

}