Wave file player:

The wave file player is yet another circuit that offers the prospect of several hours of enjoyable tinkering. The PC and the soldering iron work as partners on this project. You have to admit that this is an Elektor project in its best form. The result is a compact circuit that, on command, plays back a sound file that has been previously downloaded via the PC. The wave player can be used as a programmable doorbell, but it can also be used for model railroading or to amuse your children. Depending on the desired sampling frequency and resolution, it can store up to 43 seconds’ worth of sound.