NodeMCU & DS18B20 Sensor

This is a follow-up of my previous project using the Raspberry Pi to monitor my fridge. Now with the NodeMCU, you get a cheaper and more compact way of doing the same job.

This project combines the DS18B20 Temperature sensor with the NodeMCU. The components are as follows:

1. NodeMCU
2. DS18B20 Sensor – I got mine from Ubitap or you can get it from AliExpress
3. 4.7KΩ resistor

The DS18B20 Sensor needs to have a 4.7KΩ resistor between the VDD(3.3v) and the Data lead. So I wired it as such:

 

Notice the resistor in between the RED(3.3v) and YELLOW(Data) heads

Software

• Dallas Temperature Library
• Onewire Library
• And of course the Arduino Software

If you don’t know how to install the libraries, click here for the guide to install the arduino libraries

 

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Install the sensor

The DS18B20 sensor may come in wire color combination. Check yours set here.

I have the Red (3.3v), Black (GND) and Yellow (Data).

Wiring is as follows :

• Red – 3.3v
• Black – GND
• Yellow – D2

(Make sure you have the 4.7KΩ resistor between the Red / Yellow wires)

Code

#include <OneWire.h>
#include <DallasTemperature.h>

// Data wire is plugged into pin D2 on NodeMCU
#define sensorPin D2

// Setup the oneWire Sensor
OneWire oneWire(sensorPin);

// Pass reference to Dallas Temperature.
DallasTemperature sensors(&oneWire);

void setup(void)
{
// start serial port
Serial.begin(115200);
sensors.begin();
}

void loop(void)
{
// Get temperature
sensors.requestTemperatures();

Serial.print(“Temperature for DS18B20 is: “);
Serial.println(sensors.getTempCByIndex(0));
// 0 refers to the first IC on the wire
// accomodates more than one sensor
}

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