Hi,

1-Wire is a device networking protocol used by Dallas Semiconductors. It uses minimally a Data line (one I/O pin) that also provides power and a GND wire.

The most famous devices that use 1-Wire are, the DS18x20 digital thermometers, some RTCs, the iButton family and even some potentiometers (i have never used these though).

They are very nice devices and easy to interface. And what is most important, the manufacturer provides all the software code you need to connect them to a microcontroller. Code both in C and Assembly for 8051.

Maybe you should give them a try.
I have used 1-Wire devices for both my undergraduate and my MSc project.

Panos Kenterlis