MOTION SENSORSA Quick Glance

Early Motion Detectors Early Motion Detectors weren’t machines at

all, but human beings who kept watch. They were called sentries and often killed before they asked questions.

A Old West Sentry

Give me one

reason, varmint!

Modern Motion Detectors Modern detectors detect. A bit

obvious, I know, but that’s what they’re made to do.

It’s how they detect that defines each one.

Most sensors have a range of 15-25 meters and are usually connected to automated lights or burglar alarms.

What Motion Sensors Are Not

People have this idea that because of how fast technology is improving, that sensors see and hear everything.

But sensors can be fooled and should not be used alone. Also, they are not as interesting to look at as some of these fictional motion sensors.

DANGER! DANGER!

CRASH

CRAS

H

Passive vs. Active

Passive detectors react to signals, such as sound waves or heat spikes.

Active detectors emit signals that are reflected back to the sensor.

Passive Infrared (PIR) Passive Infrared Detectors use a sensor that detects

infrared radiation. The PIR considers a temperature range as “normal”

and anything else as reason to raise the alarm. This range is usually between 59-68°F. Sudden changes in temperature trip the detector.

Ultrasonic Detectors These are active sensors that emit ultrasonic waves

that reflect off objects. An object in motion will reflect faster because the

distance between the detector and the object is shorter.

Dual-Technology

More effective than a single-type motion sensor

False alarms are less likely to happen

Usually a combination of PIR and Microwave

Both must be activated to trip the alarm.

Need more help?

Contact the electricians at B.K. Electric Services(310) 430-2300www.bkelectricservices.com