DS18B20is 1-wire digital temperature sensor from Maxim IC suitable with 9 to12 bit precision over the range of operation (-55°C to 125°C) .
With an accuracy of ±0.5°C over the range of -10°C to +85° and multiple data logging of temperature spread in wide area network, connected in single data bus, DS18B20 comes handy as it has been assigned unique 64-Bit Serial Number, thus a single microcontroller can receive data from many DS18B20s distributed over a large area.
Unique 1-Wire® interface requires only one port pin for communication
Each device has a unique 64-bit serial code stored in an onboard ROM
Multidrop capability simplifies distributed temperature sensing applications
Requires no external components
Can be powered from data line. Power supply range is 3.0V to 5.5V
Measures temperatures from –55°C to +125°C (–67°F to +257°F)
±0.5°C accuracy from –10°C to +85°C
Thermometer resolution is user-selectable from 9 to 12 bits
Converts temperature to 12-bit digital word in 750ms (max.)
User-definable nonvolatile (NV) alarm settings
Alarm search command identifies and addresses devices whose temperature is outside of programmed limits (temperature alarm condition)
Applications include thermostatic controls, industrial systems, consumer products, thermometers, or any thermally sensitive system
Please follow the link to configure ds18b20 with raspberry pi