Connect Multiple DS18B20 1‑Wire Sensors to a Raspberry Pi for Accurate Temperature Monitoring

In this expanded guide we show how to wire and program multiple DS18B20 1‑wire temperature sensors on a Raspberry Pi, a setup ideal for solar water‑heating controllers and any system that requires differential temperature monitoring.

The DS18B20 communicates over a single data line using the 1‑wire protocol, which means you can connect several devices to the same GPIO pin. The schematic below demonstrates a three‑sensor configuration: all units share a common 3.3 V supply, a ground reference, and one data line that returns the readings to the Pi.

Because each DS18B20 contains a factory‑burned unique serial number, the Raspberry Pi can distinguish every sensor on the bus. This makes it straightforward to read and identify multiple devices with minimal wiring.

Step 1: Prepare your Pi

• Enable the 1‑wire interface: edit /boot/config.txt and add dtoverlay=w1-gpio.
• Reboot the system.

Step 2: Connect the first sensor

• Wire the sensor’s VDD to 3.3 V, GND to ground, and DQ to GPIO4 (pin 7).
• Attach a 4.7 kΩ pull‑up resistor between VDD and DQ.

Step 3: Discover the device

Run ls -l /sys/bus/w1/devices in a terminal. You’ll see a directory named 28-XXXXXXXXXXXX, where the eight hexadecimal digits are the sensor’s unique ID.

Step 4: Label and repeat

• Mark the sensor’s serial number on a label and note its physical location.
• Add the second sensor, run the ls command again, and capture its ID.
• Continue until all sensors are connected and catalogued.

Once you have identified each unit, you can address them individually in your Python or C programs by referring to the 28-XXXXXXXXXXXX directory that corresponds to the desired sensor.

For more in‑depth instructions, refer to the full guide Measure temperatures with a 1‑wire DS18B20 sensor and Raspberry Pi.