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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
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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)
- DQ 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.
Wiring Diagram between DS18B20 Temperature Sensor and ESP32
- With breadboard
This image is created using Fritzing. Click to enlarge image
- Without breadboard
This image is created using Fritzing. Click to enlarge image
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 21 // ESP32 pin GIOP21 connected to DS18B20 sensor's DQ 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
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
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Clear output
9600 baud
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