Make Electronics

Chips, Ahoy! 203

Experiment 20: A Powerful Combination

Power Up

button on

computer

Solder

joints

Heat-shrink tubing

(not yet shrunk)

To your

latching

relay

Connector

Computer motherboard

Figure 4-85. The combination lock project can be interfaced with a typical desktop com-
puter by cutting one conductor in the wire from the “power up” pushbutton, soldering an
extension, and covering the joints with heat-shrink tube.

Enhancements

At the end of any project, there’s always more you can do.

To make this setup more secure, you could remove the usual screws that secure
the case of the computer, and replace them with tamper-proof screws. Check any
online source for “tamper-proof screws,” such as http://www.mcmaster.com. Natu-
rally, you will also need the special tool that fits the screws, so that you can install
them (or remove them, if your security system malfunctions for any reason).