Need help publishing data from thingsboard and receiving it on arduino

Using Arduino Project Guidance
1

So this is my code, however this code is only able establish a connection with thingsboard MQTT broker. However what I want to do is to receive the payload on arduino is that possible? Can anyone help me with that?

arduino ---MQTT connection ---> Thingsboard server.
how to receive the data on arduino? <--- data payload

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

/*-----relayPin------*/
const int relayPin = D1;

// WiFi connection details
const char* ssid = "****";
const char* password = "****";

// ThingsBoard connnection details
const char* mqtt_server = "****";
const int mqtt_port = 1883;
const char* token = "****";
const char* subscribe_topic = "v1/devices/me/telemetry";

// Initialize WiFi and MQTT client objects
WiFiClient espClient;
PubSubClient client(espClient);

unsigned long lastMsg = 0;
#define MSG_BUFFER_SIZE (50)
char msg[MSG_BUFFER_SIZE];
String incomingMessage;

/*-----root certificate-------*/
constexpr char ROOT_CERT[] = R"(-----BEGIN CERTIFICATE-----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=
-----END CERTIFICATE-----
)";
// Function to connect to the WiFi network
void setup_wifi() {
    delay(10);
    Serial.println();
    Serial.print("Connecting to ");
    Serial.println(ssid);

    WiFi.begin(ssid, password);

    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
    }

    Serial.println("");
    Serial.println("WiFi connected");
    Serial.println("IP address: ");
    Serial.println(WiFi.localIP());
}

// Function to connect to the MQTT broker
void reconnect() {
    while (!client.connected()) {
        Serial.print("Attempting MQTT connection...");
        if (client.connect("ESP8266Client", token, NULL)) {
            Serial.println("connected");
            client.subscribe("co2");
        } else {
            Serial.print("failed, rc=");
            Serial.print(client.state());
            Serial.println(" try again in 5 seconds");
            delay(5000);
        }
    }
}


// Function to handle incoming telemetry data
void callback(char* topic, byte* payload, unsigned int length) {
    Serial.print("Message arrived on topic: ");
    Serial.println(topic);
    
    // Convert payload to a JSON string
    payload[length] = '\0';  // Null-terminate the payload
    String jsonString = String((char*)payload);

    // Parse the JSON string
    StaticJsonDocument<200> doc;
    DeserializationError error = deserializeJson(doc, jsonString);

    if (error) {
        Serial.print("deserializeJson() failed: ");
        Serial.println(error.f_str());
        return;
    }

    // Extract the CO2 value
    if (doc.containsKey("co2") && doc["co2"].as<int>() > 1000) {
        if (incomingMessage.equals("1")) {
            digitalWrite(relayPin, HIGH);
        } else {
            digitalWrite(relayPin, LOW);
        }
    }
}

void setup() {
    Serial.begin(115200);
    Serial.print("start");
    setup_wifi();
    client.setServer(mqtt_server, mqtt_port);
    client.setCallback(callback);
}

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

    DynamicJsonDocument doc(1024);
    doc["deviceId"] = "CO2 Sensor";


    char mqtt_message [128];
    serializeJson(doc, mqtt_message, true);

    delay(5000);
}

`

The expected outcome is to receive co2 data on arduino such that if co2> 1500, the relay will be HIGH.

2

Does anyone know how to parse data from thingsboard to esp8266 using arduino ide? I managed to connect to the mqtt broker on port 1883 but thats about it

3

I have merged your topics due to them having too much overlap on the same subject matter @tb_user.

I also removed your various posts requesting assistance on various other people's topics.

In the future, please only create one topic for each distinct subject matter and be careful not to cause them to converge into parallel discussions.

The reason is that generating multiple threads on the same subject matter can waste the time of the people trying to help. Someone might spend a lot of time investigating and writing a detailed answer on one topic, without knowing that someone else already did the same in the other topic.

You can learn about the expected forum etiquette from the "How to get the best out of this forum" guide. It contains a lot of useful information. Please read it.

Thanks in advance for your cooperation.

4

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