We have for a long time wanted a temperature logger and this has resulted in this project. We choose to interface the thermometer through USB as this is todays best standard. When the thermometer is connected to the PC you operate it through my brothers program written in Realbasic.
Update: On request from Andre in Russia we have updated the pic program to enable it to use a DS18B20 thermometer chip with 0.1 C resolution. The Windows software is updated accordingly.
Click on the picture to enlarge it and read our comments and advice
Bottom side of the pcb, close up on the small SMD crystal for the real time clock.