DS18B20 is a digital temperature sensor manufactured by the Dallas Semiconductor Company. It gives 9-to 12-bit temperature readings.

DS18B20 has three pins, ground (GND), Data line (DQ), and power supply (VDD), as shown in the following diagram:

There is one more package available for these sensors, shown in the following figure, which is a waterproof version of DS18B20:

DS18B20 communicates with Raspberry Pi or any other controller device using the Dallas one-wire communication protocol. Raspberry Pi has provisions for sensors that communicate over the Dallas one-wire protocol, which makes the integration of this sensor pretty easy and straightforward.

The Dallas one-wire protocol is a serial communication method where data is transferred bit by bit over DQ. It is designed for simple communication between one master and multiple slave devices. In our case, Raspberry Pi is the master and the DS18B20 temperature sensor is the slave, which means we can integrate more than one temperature sensor on the same one-wire interface.

DS18B20 has a unique, factory-set, unchangeable device ID, using which each individual sensor can be identified over one-wire communication bus, as illustrated in the following figure:

Due to this feature of interfacing multiple sensors on one data bus, DS18B20 is useful in applications such as HVAC environmental controls; sensing temperatures inside buildings, equipment, or machinery; and process monitoring and control where multiple sensors are required.