Read Temperature with DS18B20 Sensor and Arduino

DS18B20 is a temperature sensor that uses the 1-Wire protocol. It’s reasonably accurate and comes in a waterproof version, making it suitable for measuring water temperature or outdoor environments.

Required Parts

Component	Quantity
Arduino UNO R3	1
DS18B20 TO-92	1
Resistor 4.7kΩ	1
Breadboard MB-102	1
Jumper wires M-M, M-F	several
Power Adapter 9V 2A	optional

Wiring the Circuit

Follow this straightforward wiring:

Arduino	DS18B20
Pin 2	Middle pin (Data)
5V	Right pin (VCC)
GND	Left pin (GND)
5V and Pin 2	4.7kΩ resistor (pull-up)

Make sure to orient DS18B20 with the flat side facing you: left = GND, middle = Data, right = VCC.

Installing Libraries

You need 2 libraries:

1. Open Arduino IDE → Sketch → Include Library → Manage Libraries
2. Search and install OneWire (by Paul Stoffregen)
3. Search and install DallasTemperature (by Miles Burton)

Code for Reading Temperature

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

// DS18B20 connected to Arduino pin 2
#define ONE_WIRE_BUS 2

OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

void setup() {
  Serial.begin(9600);
  sensors.begin();
}

void loop() {
  sensors.requestTemperatures();
  float tempC = sensors.getTempCByIndex(0);
  
  Serial.print("Temperature: ");
  Serial.print(tempC);
  Serial.println(" °C");
  
  delay(1000);
}

Upload this code to your board, then open Serial Monitor (Tools → Serial Monitor) and set baud rate to 9600.

If wired correctly, you’ll see temperature readings every second. Try blowing warm air near the sensor—the value should increase.

Reference Video

Search for “Arduino DS18B20 tutorial” on YouTube if you want to see the wiring process in action.

Summary

• DS18B20 wiring: Data → Pin 2, VCC → 5V, GND → GND
• Add 4.7kΩ resistor between Data and VCC
• Install OneWire + DallasTemperature libraries
• Read temperature with getTempCByIndex(0)