It is a thermometer that can can from -55 º – 125 º. It is based to DS18B20 from Maxim.
It can display the max and the min temp that is measured, until reset is pressed or get of power supply
The microcontroler is Pic18F877. The pcb is very easy to construct ,there are just a few components
The dislpay is the classic HD 44780 2×16
Here is hex file you need to load to microcontroler though the suitable programmer and pcb
i have made a nice box of plexi class