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Arduino - Temperature Sensor

There are many type of temperature sensors can works with Arduino such as LM35, TH02, HDC1000 or HTS221... In this tutorial, we are going to learn how to use waterproof DS18B20 temperature sensor with Arduino. This sensor is inexpensive, easy to use and look neat.

Hardware Required

1	×	Arduino UNO or Genuino UNO
1	×	USB 2.0 cable type A/B (for USB-A PC)
1	×	USB 2.0 cable type C/B (for USB-C PC)
1	×	DS18B20 Temperature Sensor (WITH Adapter)
1	×	DS18B20 Temperature Sensor (WITHOUT Adapter)
1	×	Jumper Wires
1	×	(Recommended) Screw Terminal Block Shield for Arduino Uno
1	×	(Recommended) Breadboard Shield For Arduino Uno
1	×	(Recommended) Enclosure For Arduino Uno

Or you can buy the following sensor kits:

1	×	DIYables Sensor Kit (30 sensors/displays)
1	×	DIYables Sensor Kit (18 sensors/displays)

Disclosure: Some links in this section are Amazon affiliate links. If you make a purchase through these links, we may earn a commission at no extra cost to you.
Additionally, some links direct to products from our own brand, DIYables.

Buy Note: Many DS18B20 sensors on the market are low-quality. We highly recommend buying the sensor from the DIYables brand using the link above. We tested it, and it worked well.

About One Wire Temperature Sensor - DS18B20

Pinout

DS18B20 temperature sensor has three pins:

GND pin: needs to be connected to GND (0V)
VCC pin: needs to be connected to VCC (5V or 3.3V)
DATA pin: is 1-Wire Data bus. It should be connected to a digital pin on Arduino.

The sensor usually has two forms: TO-92 package (looks like a transistor) and waterproof probe. We use the waterproof probe form in this tutorial.

Connecting a DS18B20 temperature sensor to an Arduino requires a pull-up resistor, which can be a hassle. However, some manufacturers simplify the process by offering a wiring adapter that has a built-in pull-up resistor and a screw terminal block, making it much easier.

Wiring Diagram

Wiring diagram with breadboard

This image is created using Fritzing. Click to enlarge image

Wiring diagram with adapter (recommended)

This image is created using Fritzing. Click to enlarge image

Real wiring diagram with adapter

This image is created using Fritzing. Click to enlarge image

We suggest purchasing a DS18B20 sensor that comes with a wiring adapter for easy connection. The adapter has a built-in resistor, eliminating the need for a separate one in the wiring.

How To Program For DS18B20 Temperature Sensor

Include the library:

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

Declare OneWire and DallasTemperature object corresponding to the pin connected to sensor's DATA pin

OneWire oneWire(SENSOR_PIN); // setup a oneWire instance DallasTemperature sensors(&oneWire); // pass oneWire to DallasTemperature library

Initialize the sensor:

sensors.begin(); // initialize the sensor

Send the command to get temperatures:

sensors.requestTemperatures();

Read temperature in Celsius:

tempCelsius = sensors.getTempCByIndex(0);

(Optional) Convert Celsius to Fahrenheit:

tempFahrenheit = tempCelsius * 9 / 5 + 32;

Arduino Code

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-temperature-sensor */ #include <OneWire.h> #include <DallasTemperature.h> const int SENSOR_PIN = 13; // Arduino pin connected to DS18B20 sensor's DQ pin OneWire oneWire(SENSOR_PIN); // setup a oneWire instance DallasTemperature tempSensor(&oneWire); // pass oneWire to DallasTemperature library float tempCelsius; // temperature in Celsius float tempFahrenheit; // temperature in Fahrenheit void setup() { Serial.begin(9600); // initialize serial tempSensor.begin(); // initialize the sensor } void loop() { tempSensor.requestTemperatures(); // send the command to get temperatures tempCelsius = tempSensor.getTempCByIndex(0); // read temperature in Celsius tempFahrenheit = tempCelsius * 9 / 5 + 32; // convert Celsius to Fahrenheit Serial.print("Temperature: "); Serial.print(tempCelsius); // print the temperature in Celsius Serial.print("°C"); Serial.print(" ~ "); // separator between Celsius and Fahrenheit Serial.print(tempFahrenheit); // print the temperature in Fahrenheit Serial.println("°F"); delay(500); }

Quick Steps

Connect Arduino to PC via USB cable
Open Arduino IDE, select the right board and port
Navigate to the Libraries icon on the left bar of the Arduino IDE.
Search “DallasTemperature”, then find the DallasTemperature library by Miles Burton.
Click Install button to install DallasTemperature library.

You will be asked to install the library dependency
Click Install All button to install OneWire library.

Copy the above code and open with Arduino IDE
Click Upload button on Arduino IDE to upload code to Arduino
Put the sensor on hot and cold water, or grasp the sensor by your hand
See the result on Serial Monitor.

COM6

Send

Temperature: 26.31°C ~ 79.36°F Temperature: 26.44°C ~ 79.59°F Temperature: 26.50°C ~ 79.70°F Temperature: 26.56°C ~ 79.81°F Temperature: 27.06°C ~ 80.71°F Temperature: 27.75°C ~ 81.95°F Temperature: 28.37°C ~ 83.07°F Temperature: 29.00°C ~ 84.20°F Temperature: 29.56°C ~ 85.21°F Temperature: 30.00°C ~ 86.00°F Temperature: 30.31°C ~ 86.56°F Temperature: 30.62°C ~ 87.12°F Temperature: 30.87°C ~ 87.57°F

Autoscroll Show timestamp

Clear output

9600 baud

Newline

Video Tutorial

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Temperature Sensor on Commercial Products

Medical Thermometer

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Arduino - Temperature Sensor

Hardware Required

About One Wire Temperature Sensor - DS18B20

Pinout

Wiring Diagram

How To Program For DS18B20 Temperature Sensor

Arduino Code

Quick Steps

Video Tutorial

Temperature Sensor on Commercial Products

The Best Arduino Starter Kit

See Also