Laser-controlled burglar deterrent:
Since the 1960s, light-emitting diodes (LEDs) have come into
use for many applications. Many people may not know that
these diodes, used in low-cost laser-pens and laser pointers,
were developed for CD players. Today, lasers are used in
architecture, in automobile engineering to measure all sorts of
part, and in high-precision spirit levels, to name but a few.
Lasers are also used in crime fighting, for instance, in highprecision
speed traps to catch the unwary, speeding motorist.
These are but a few examples of the many applications of
lasers. This article describes how a simple laser diode can be
used to build an inexpensive burglar deterrent/alarm.