
                         Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: TUESDAY, March 21, 1995                   TAG: 9503210130
SECTION: EXTRA                    PAGE: 3   EDITION: METRO 
SOURCE: DAVID BUTLER
DATELINE:                                 LENGTH: Medium

MOTION SENSORS HAVE MANY USES

Q: I'd like several of my outdoor lights to come on automatically when someone approaches. The only type of motion-activated lights I've seen is the kind with dual floodlamps. What other styles are available? Also, can I use a motion sensor to operate an overhead light in a closet or utility room?

A: Until recently, a security floodlight would have been your only option if you wanted to install a motion-activated light. Now you can choose from a variety of decorative fixtures in styles ranging from polished brass coach lights to antique brass carriage lights and from black enamel lanterns to glossy white globe lights.

The motion sensors used in automatic light fixtures are similar to those found in home security systems. An infrared eye responds to the temperature contrast as a person or vehicle passes through its detection zone. However, unlike security detectors, motion-activated lights have a built-in timer that turns the light off after a user-adjustable delay.

Replacing fixtures is not a prerequisite to having motion-activated lights - several companies offer add-on switches for existing fixtures. Two types are available: wired-in and screw-in. Wired-in motion switches must be connected in line with the fixture's electrical circuit. Screw-in motion switches are easiest to install. An adapter screws in between the bulb and socket. With some models the motion sensor is part of the adapter while with others, it's connected by a short tether.

The latest motion detectors rely on pulse count technology and other signal processing techniques to keep birds and falling leaves from triggering a response. Also, detection zones are getting wider - up to 180 degrees on some models. One security fixture can even see around corners. When mounted on an outside corner, its 270-degree multizone sensor does the job of two.

Perhaps the most unusual security floodlight not only turns itself on, but can remotely switch on another light. The second light must be plugged into a PLC (power line carrier) receiver module. You could also use this feature to sound a chime module when someone pulls into your driveway.

Indoors, the easiest way to automate a fixture is to install a replacement wall switch with a built-in motion sensor. Some models have a security mode that simulates occupancy. Three- and four-way versions are also available. Plug-in motion switches can be used with lamps. Several companies make ceiling-mounted detectors that cover an entire room. Special wiring is required.

A wall-switch detector wouldn't be practical for a closet since it would activate the light whenever someone enters the room. Here's a better solution: An 18-inch fluorescent fixture is available with a built-in motion sensor. Otherwise, you may want to consider installing a door-frame plunger switch.

Virtually all motion-activated lights have a built-in photocell to prevent daytime operation. Most include a sensitivity adjustment, which overrides this feature when turned to one extreme. This way you can use a motion-activated switch in an area that needs additional light during the day, such as a stairway or hallway.

To receive a list of companies that manufacture motion-activated light fixtures and switches, please send $1.50 and a self-addressed envelope to David Butler F-502, Department TWN, 14713 Pleasant Hill Road, Charlotte, N.C. 28278-7927. The list includes toll-free phone numbers and a summary of each company's products. You'll also receive sources for three motion-activated fixtures that operate on solar power.

by CNB