You don't have to monkey with a cable or other "drive-over" device to install Lane Sentry, a new driveway alarm from S.A. Clark and Associates, Marion, Iowa.

The Lane Sentry system utilizes a probe (12 in. long and 1 in. in dia.) which is buried at the side of the driveway. When any moving metal object passes within 14 ft. of the probe, it activates an alarm located back at headquarters in the home (or in your workshop or wherever else you decide to put it). The probe detects cars, trucks and tractors entering the farm but isn't "tripped" by children or animals. Also, since it requires no "drive over" cable or wire, Lane Sentry isn't bothered by snow or mud, the manufacturer points out.

The unit isn't completely wireless, however, in that you do have to run a wire just below ground between the probe and the alarm. Effective range of the system (from probe to alarm) is up to 1,000 ft.

The system is capable of functioning in two modes -- "ANNOUNCE" or "ALARM". During the day, when the console (located in the home) is set to the ANNOUNCE mode, the system will emit a shrill beep in the home whenever a vehicle is detected -- in effect becoming an additional doorbell for the farmstead. Although the probe's primary use is in monitoring the farm or ranch driveway, it can also be used in other locations on the farmstead, such as near gas tanks or in grain storage areas.

During the evening, when the console is set to the ALARM mode, the system will also activate living room lights, yard lights, or other alarm devices, according to the manufacturer.

The system is also equipped with a 21 minute EXIT DELAY feature which permits the owner to leave the premises without sounding the alarm.