Security lighting is the best preventative measure that you can take for home security. This may include outdoor motion lights or other such lighting for burglary deterrence and nighttime security purposes. Security lighting can be used in residential, commercial, industrial, institutional, and military settings.
Other lights may be activated by sensors such as passive infrared sensors (PIRs), turning on only when a person (or other mammal) approaches. PIR activated lamps will usually be incandescent bulbs so that they can activate instantly; energy saving is less important since they will not be on all the time. PIR sensor activation can increase both the deterrent effect (since the intruder knows that he has been detected) and the detection effect (since a person will be attracted to the sudden increase in light). Some PIR units can be set up to sound a chime as well as turn on the light. Most modern units have a photocell so that they only turn on when it is dark.
Security lighting is often used as a preventive and corrective measure against intrusions or other criminal activity on a physical piece of property. Security lighting may be provided to aid in the detection of intruders, to deter intruders, or in some cases simply to increase the feeling of safety. Lighting is integral to crime prevention through environmental design.