Measuring room or object temperatures with the DS18B20. It is a digital component wich does all the work for you. You only need to COMMAND it do the measurement. A short moment later you can request 2 bytes containing the temperature.
Of course there is a protocal wich says how to communicate. See 1-Wire and the DS18B20 datasheet.
How 1-Wire works (by Maxim): http://www.maxim-ic.com/products/1-wire/flash/overview/index.cfm
- FLASH: 4096 Words
- RAM: 256 Bytes
- IO Pins: 18
- Clock internal: 8MHz internal, 4MHz default config
- Clock external:up to 20MHz external
- LCD 2×16, HD44780 Compatible