The Time Machine Radio lets you go back in time and listen to those old songs which will bring up happy memories. You set the knob to the year you want to listen music from and the radio will start to play the stuff you like.

The radio has an Arduino board which transfers the data from the knobs to a flash application which runs on an Asus Eee 901.

You can find a detailed site and more pictures about building the radio here.

Here is the original:
Time Machine Radio: Enter the past