This 3-digit digital thermometer is easy to build for beginners or hobbyits. PIC16F628 is used to read digital values of temperature from a DS1820 sensor. All 7-segments are driven by a power logic 8-bit shift register TPIC6B595 with open collector output. For the 7-segment we need 12V volt to drive it because it has 3 LED per one segment. Source code in C Compiler is available.
3-Digit Digital Thermometer: [Link]