A programmer who's got some knowledge of parallel port programming can make a Computer death trap.It's really easy to produce 7hz signal using an electronic circuit. Hook up the thing to the parallel port and write a program in C which controls he device ( parallel port programming is kindda easy and the programs aren't all that huge as some people say ).You
could like activate the device when someone tries to get illegal physical access or something !!!...wait a sec ...that's too harsh rite ????