ESP8266 NodeMCU v3 and DS18B20: Sensors not detected

[TomaszFilipek]

Hello,

I have a WiFi module ESP8266 + NodeMCU v3 to which I have connected two DS18B20 sensors to pin D7.

For some reason, the sensors are not being detected.
Please advise why.

Code: main.cpp Select all

#include <Arduino.h>

#include "TemperatureSensorController.cpp"



TemperatureSensorController temperatureSensorController;



void setup()

{

  Serial.begin(115200);



  temperatureSensorController = TemperatureSensorController(D7);

}



void loop()

{

  temperatureSensorController.printTemperatures();

  

  delay(1000);

}

Code: TemperatureSensorController.cpp Select all

#include <DallasTemperature.h>

#ifndef MYCLASS_H

#define MYCLASS_H



class TemperatureSensorController

{

public:

    TemperatureSensorController()

    {

    }



    TemperatureSensorController(uint8_t oneWireBus) : TemperatureSensorController()

    {

        _oneWire = OneWire(oneWireBus);

        _sensors = DallasTemperature(&_oneWire);

    }



    void printTemperatures()

    {  

        Serial.println("Print Temperatures");

        Serial.println("");



        delay(100);



        _sensors.begin();



        delay(100);



        _sensors.requestTemperatures();



        Serial.print("Device count: ");

        Serial.println(_sensors.getDeviceCount());

        Serial.println("");



        for (int i = 0; i < _sensors.getDeviceCount(); i++)

        {

            Serial.print("Device no. ");

            Serial.print(i + 1);

            Serial.print(" Temperature: ");

            Serial.print(_sensors.getTempCByIndex(i));

            Serial.println(" °C");

            delay(100);

        }



        Serial.println("");

        Serial.println("-----------------------");

        Serial.println("");

    }



public:

    OneWire _oneWire;

    DallasTemperature _sensors;

};



#endif

Output of the program:

X.jpg (17.3 KiB) Viewed 3379 times

The physical connections are fine - running the code where everything is in the main.cpp file, the readings are done correctly.

Code: main.cpp Select all

#include <Arduino.h>

#include "TemperatureSensorController.cpp"



OneWire oneWire = OneWire(D7);

DallasTemperature sensors = DallasTemperature(&oneWire);



void setup()

{

  Serial.begin(115200);



  sensors.begin();

}



void loop()

{

  Serial.println("Print Temperatures");

  Serial.println("");



  delay(100);



  sensors.begin();



  delay(100);



  sensors.requestTemperatures();



  Serial.print("Device count: ");

  Serial.println(sensors.getDeviceCount());

  Serial.println("");



  for (int i = 0; i < sensors.getDeviceCount(); i++)

  {

    Serial.print("Device no. ");

    Serial.print(i + 1);

    Serial.print(" Temperature: ");

    Serial.print(sensors.getTempCByIndex(i));

    Serial.println(" °C");

    delay(100);

  }



  Serial.println("");

  Serial.println("-----------------------");

  Serial.println("");



  delay(5000);

}

Output:

V.jpg (38.08 KiB) Viewed 3379 times

Thank you in advance for your help.