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IoT Devices
1
Summary

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3

Hello @amrokhalifa,

Can you please print the topic and the payload to make sure they’re valid and according to what’s expected by the MQTT broker.
For the time being, note that the labels, both of Devices or Variables, must be all lowercase and can only contain alphanumeric characters, dashes and underscores. This means that you should avoid white-spaces like the one in your DEVICE_LABEL variable.

-Sebastian

5

Hi @amrokhalifa

Can you print the topic and payload your building in the code to the serial monitor and then, if you still have issues uploading the picture, simply copy and paste both of then here to check them up?
To do so, use the below lines and include them in your code just before calling the client.publish() method.

Serial.println(topic);
Serial.println(payload);

Thank you.

10

Notice that your payload does not fit the expected JSON structure that you may reference in our docs. It should looks like as follows:

{"VARIABLE-LABEL_1": {"value":VALUE, "context":{"KEY":VALUE}}, ··· , "VARIABLE-LABEL_N": {"value":VALUE, "context":{"KEY": VALUE}}}

UPDATE: Here’s simpler structure yet valid. This works only to send the values.

{"VARIABLE-LABEL_1": VALUE, ··· , "VARIABLE-LABEL_N": VALUE}

Variables are created automatically, just fix your payload and everything should go on the wheels.

All the best

12

Hello @amrokhalifa,

This is the code to publish your 2 temperatures variables to Ubidots correctly. If everything goes as expected, you should see a new device in the Devices section

// INCLUDE LIBRARIES
#include <DallasTemperature.h>
#include <OneWire.h>
#include <WiFi.h>
#include <PubSubClient.h>

#define WIFISSID "Flat 9"
#define PASSWORD "CxDkE9VGQScP"
#define TOKEN "xxxxxxxxxxxxxxxxxxxx" // Ubidots Token

// DEFINe CONSTANTS
#define MQTT_CLIENT_NAME "AmroKhalifa2020"
#define Pin D4int temp;
#define ONE_WIRE_BUS 4 // set pin GPIO 4 as sensors

OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

const char *VARIABLE_LABEL_1 = "temp1";                 // Assign the variable label
const char *VARIABLE_LABEL_2 = "temp2";                 // Assign the variable label
const char *DEVICE_LABEL = "temperature_project";   // Assign the device label

char mqttBroker[] = "industrial.api.ubidots.com";
char payload[300];
char topic[150];

char str_Temp1[10];
char str_Temp2[10];

WiFiClient ubidots;
PubSubClient client(ubidots);

void callback(char *topic, byte *payload, unsigned int length)
{
    char p[length + 1];
    memcpy(p, payload, length);
    p[length] = NULL;
    String message(p);
    Serial.write(payload, length);
    Serial.println(topic);
}

void reconnect()
{
    while (!client.connected())
    {
        Serial.println("Attempting MQTT connection...");

        // Attempt to connect
        if (client.connect(MQTT_CLIENT_NAME, TOKEN, ""))
        {
            Serial.println("Connected");
        }
        else
        {
            Serial.print("Failed, rc=");
            Serial.print(client.state());
            Serial.println(" try again in 2 seconds");
            delay(2000); //wait 2 seconds before retrying
        }
    }
}

void setup()
{
    Serial.begin(115200);
    sensors.begin();

    WiFi.begin(WIFISSID, PASSWORD);
    Serial.println();
    Serial.print("Wait for WiFi...");

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

    Serial.println("");
    Serial.println("WiFi Connected");
    Serial.println("IP address: ");
    Serial.println(WiFi.localIP());
    client.setServer(mqttBroker, 1883);
    client.setCallback(callback);

    // Builds the topic. As it won't change, it can be done in the Seyup function
    sprintf(topic, "%s%s", "/v1.6/devices/", DEVICE_LABEL);
}

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

    sensors.requestTemperatures();
    float Temp1 = sensors.getTempCByIndex(0);
    float Temp2 = sensors.getTempCByIndex(1);

    /* 4 is mininum width, 2 is precision; float value is copied onto str_sensor*/
    dtostrf(Temp1, 4, 2, str_Temp1);
    dtostrf(Temp2, 4, 2, str_Temp2);

    sprintf(payload, "%s", "");                                                 // Cleand the payload
    sprintf(payload, "{\"%s\": %s,", VARIABLE_LABEL_1, str_Temp1);              // Adds the variable label 1 and its value
    sprintf(payload, "%s\"%s\": %s}", payload, VARIABLE_LABEL_2, str_Temp2);    // Adds the variable label 2 and its value

    Serial.print("Temp1 = ");
    Serial.println(Temp1);
    Serial.print("Temp2 = ");
    Serial.println(Temp2);
    Serial.println("Publishing data to Ubidots Cloud");
    Serial.println(payload);
    client.publish(topic, payload);
    client.loop();
    delay(5000);
}

I used the below article as reference

Best,

–David