DS18B20 is a probe type waterproof temperature sensor, gives 9 to 12-bit Celsius temperature measurement and has an alarm function with non-volatile. The user can programme upper and lower trigger points. It has a 1-Wire bus to communicate with the sensor. This sensor has a unique 64-bit serial code, because of that multiple sensors can function at the same time on the 1-Wire bus and with one microprocessor.
It has an additional feature to drive power directly from data lines, it eliminates the external power supply requirement.