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: [Select all] [Expand/Collapse]

1. #include <Arduino.h>
2. #include "TemperatureSensorController.cpp"
3.  
4. TemperatureSensorController temperatureSensorController;
5.  
6. void setup()
7. {
8.   Serial.begin(115200);
9.  
10.   temperatureSensorController = TemperatureSensorController(D7);
11. }
12.  
13. void loop()
14. {
15.   temperatureSensorController.printTemperatures();
16.  
17.   delay(1000);
18. }

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Code: [Select all] [Expand/Collapse]

1. #include <DallasTemperature.h>
2. #ifndef MYCLASS_H
3. #define MYCLASS_H
4.  
5. class TemperatureSensorController
6. {
7. public:
8.     TemperatureSensorController()
9.     {
10.     }
11.  
12.     TemperatureSensorController(uint8_t oneWireBus) : TemperatureSensorController()
13.     {
14.         _oneWire = OneWire(oneWireBus);
15.         _sensors = DallasTemperature(&_oneWire);
16.     }
17.  
18.     void printTemperatures()
19.     {  
20.         Serial.println("Print Temperatures");
21.         Serial.println("");
22.  
23.         delay(100);
24.  
25.         _sensors.begin();
26.  
27.         delay(100);
28.  
29.         _sensors.requestTemperatures();
30.  
31.         Serial.print("Device count: ");
32.         Serial.println(_sensors.getDeviceCount());
33.         Serial.println("");
34.  
35.         for (int i = 0; i < _sensors.getDeviceCount(); i++)
36.         {
37.             Serial.print("Device no. ");
38.             Serial.print(i + 1);
39.             Serial.print(" Temperature: ");
40.             Serial.print(_sensors.getTempCByIndex(i));
41.             Serial.println(" °C");
42.             delay(100);
43.         }
44.  
45.         Serial.println("");
46.         Serial.println("-----------------------");
47.         Serial.println("");
48.     }
49.  
50. public:
51.     OneWire _oneWire;
52.     DallasTemperature _sensors;
53. };
54.  
55. #endif

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Output of the program:

X.jpg (17.3 KiB) Viewed 2344 times

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

Code: [Select all] [Expand/Collapse]

1. #include <Arduino.h>
2. #include "TemperatureSensorController.cpp"
3.  
4. OneWire oneWire = OneWire(D7);
5. DallasTemperature sensors = DallasTemperature(&oneWire);
6.  
7. void setup()
8. {
9.   Serial.begin(115200);
10.  
11.   sensors.begin();
12. }
13.  
14. void loop()
15. {
16.   Serial.println("Print Temperatures");
17.   Serial.println("");
18.  
19.   delay(100);
20.  
21.   sensors.begin();
22.  
23.   delay(100);
24.  
25.   sensors.requestTemperatures();
26.  
27.   Serial.print("Device count: ");
28.   Serial.println(sensors.getDeviceCount());
29.   Serial.println("");
30.  
31.   for (int i = 0; i < sensors.getDeviceCount(); i++)
32.   {
33.     Serial.print("Device no. ");
34.     Serial.print(i + 1);
35.     Serial.print(" Temperature: ");
36.     Serial.print(sensors.getTempCByIndex(i));
37.     Serial.println(" °C");
38.     delay(100);
39.   }
40.  
41.   Serial.println("");
42.   Serial.println("-----------------------");
43.   Serial.println("");
44.  
45.   delay(5000);
46. }

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Output:

V.jpg (38.08 KiB) Viewed 2344 times

Thank you in advance for your help.