ESP32 - Temperature Sensor

This tutorial instructs you how to use ESP32 to read the temperature from DS18B20 temperature sensor and print it to Serial Monitor.

Hardware Used In This Tutorial

1	×	ESP-WROOM-32 Dev Module
1	×	USB Cable Type-C
1	×	Temperature Sensor DS18B20
1	×	Breadboard
1	×	Jumper Wires
1	×	(Optional) DC Power Jack
1	×	(Recommended) ESP32 Screw Terminal Adapter

Or you can buy the following sensor kit:

DIYables Sensor Kit 30 types, 69 units

Disclosure: some of these links are affiliate links. We may earn a commission on your purchase at no extra cost to you. We appreciate it.

Buy Note: Numerous DS18B20 sensors available in the market are of poor quality. We strongly advise purchasing the sensor from the DIYables brand via the link above; we conducted tests, and it performed reliably.

Introduction to One Wire Temperature Sensor - DS18B20

DS18B20 Temperature Sensor Pinout

DS18B20 temperature sensor has three pins:

GND pin: connect this pin to GND (0V)
VCC pin: connect this pin to VCC (5V or 3.3V)
DATA pin: is 1-Wire Data Bus. It should be connected to a digital pin on ESP32.

The DS18B20 sensor has two forms:

TO-92 package (looks similar to a transistor)
Waterproof probe. We use this form in this tutorial.

Connecting a DS18B20 temperature sensor with an Arduino often requires a pull-up resistor, which can be a hassle. However, some manufacturers have made the process simpler by offering a wiring adapter with a built-in pull-up resistor and a screw terminal block for easy connection.

Wiring Diagram between DS18B20 Temperature Sensor and ESP32

With breadboard

This image is created using Fritzing. Click to enlarge image

If you're unfamiliar with how to supply power to the ESP32 and other components, you can find guidance in the following tutorial: How to Power ESP32.

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

For ease of connection, it's advisable to purchase a DS18B20 sensor that comes with a wiring adapter equipped with a built-in resistor, eliminating the need for an additional resistor in the wiring.

ESP32 Code

/* * This ESP32 code is created by esp32io.com * * This ESP32 code is released in the public domain * * For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-temperature-sensor */ #include <OneWire.h> #include <DallasTemperature.h> #define SENSOR_PIN 17 // ESP32 pin GPIO17 connected to DS18B20 sensor's DATA pin OneWire oneWire(SENSOR_PIN); DallasTemperature DS18B20(&oneWire); float tempC; // temperature in Celsius float tempF; // temperature in Fahrenheit void setup() { Serial.begin(9600); // initialize serial DS18B20.begin(); // initialize the DS18B20 sensor } void loop() { DS18B20.requestTemperatures(); // send the command to get temperatures tempC = DS18B20.getTempCByIndex(0); // read temperature in °C tempF = tempC * 9 / 5 + 32; // convert °C to °F Serial.print("Temperature: "); Serial.print(tempC); // print the temperature in °C Serial.print("°C"); Serial.print(" ~ "); // separator between °C and °F Serial.print(tempF); // print the temperature in °F Serial.println("°F"); delay(500); }

Quick Instructions

If this is the first time you use ESP32, see how to setup environment for ESP32 on Arduino IDE.
Do the wiring as above image.
Connect the ESP32 board to your PC via a micro USB cable
Open Arduino IDE on your PC.
Select the right ESP32 board (e.g. ESP32 Dev Module) and COM port.
On Arduino IDE, Navigate to Tools Manage Libraries

Type “OneWire” on the search box, then look for the OneWire library by Paul Stoffregen
Click Install button to install OneWire library.

Type “Dallas” on the search box, then look for the DallasTemperature library by Miles Burton.
Click Install button to install DallasTemperature library.

Copy the above code and paste it to Arduino IDE.
Compile and upload code to ESP32 board by clicking Upload button on Arduino IDE
Make the sensor hotter or colder by gripping the DS18B20 temerature sensor on your hand, or embedding it on hot and cold water.
See the result on Serial Monitor. It looks like the below:.

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

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