Are interested in using a 74c922 keypad encoder chip for a 4x4 keypad. I can give you a link to a project I posted in the Gallery. Also, do you want to use ONEWIRE DS18B20 3-pin digital temp sensors (16 bit resolution) ? I can give some example programs. You could use a 6-digit 7-segment lcd. I can give you the link and an example program. The demo comes with a count up timer example.