How to Connect a DS18B20 One‑Wire Digital Thermometer to a Raspberry Pi – A Step‑by‑Step Guide

While searching for a simple way to measure temperature with a Raspberry Pi, I discovered the DS18B20 1‑wire digital temperature sensor. Its accuracy—±0.5 °C at 0 °C—and minimal wiring make it ideal for beginners and seasoned makers alike.

The sensor is inexpensive, requires only a single 4.7 kΩ pull‑up resistor, and fits easily into a breadboard or a TO‑92 package that resembles common transistors.

Below is a quick wiring diagram and the steps to get your Pi talking to the DS18B20.

Pinout (TO‑92)

• Pin 1: GND
• Pin 2: DQ (data)
• Pin 3: VDD (3.3 V)

Connect the sensor to the Pi as follows:

• Pin 1 → P1‑06 (Ground)
• Pin 2 → P1‑07 (GPIO 4)
• Pin 3 → P1‑01 (3.3 V)

A 4.7 kΩ resistor must be placed between the data line (Pin 2) and the 3.3 V supply (Pin 3). If you don’t have a 4.7 kΩ resistor, two 2.2 kΩ resistors in series will work fine.

After wiring, power up the Pi. It’s a good idea to use a fresh SD card with the latest Raspberry Pi OS (formerly Raspbian). Download it from the official Raspberry Pi Software page.

Keep the system updated with:

sudo apt-get update && sudo apt-get upgrade

Next, enable the 1‑Wire interface by editing /boot/config.txt:

sudo nano /boot/config.txt

Add the following line at the end:

dtoverlay=w1-gpio,gpiopin=4

Save the file (Ctrl + X, Y, Enter) and reboot:

sudo reboot

Once the Pi restarts, the DS18B20 will appear in the /sys/bus/w1/devices directory. To read the temperature, use:

cat /sys/bus/w1/devices/28-xxxxxxxxxxxx/w1_slave

Replace 28-xxxxxxxxxxxx with the sensor’s unique ID.

For detailed documentation, refer to the DS18B20 datasheet and the official Raspberry Pi GPIO guide.