Due to vehicular damage and convenience, many homeowners install devices to detect objects in the path of a closing driveway gate. They trigger a motor that reverses the gate's motion. Although they are not a necessary component of automatic gates they provide a level of comfort that many consumers find necessary.
In addition, these devices may supplement a gate's operation by automatically opening the gate only for exiting vehicles. This may serve as a convenience for some people who may be engrossed in other concerns and thus do not have to take any action. Thus, they simultaneously enhance safety and convenience.
Gate Controls with Infrared Detectors
Many consumers choose these devices to operate gate exits. An infrared (also known as infra-red) sensor senses objects when the object breaks its beam of infrared light. The emitter first emits a beam of infra-red light. A typical effective length for the beam may range from thirty to seventy-five feet.
If the beam strikes an object, the beam is reflected back to the unit's detector and the unit sends a signal to the gate relay to operate the motor. If objects do not break the path of the beam then the unit is not activated. Depending on your budget, you may want to choose a unit that is unaffected by rain, dust, and other weather-related occurrences.
Exit Wands and Loop Detectors for Driveway Gates
Both exit wands and loop detectors operate on the principle of electromagnetic induction. That is, the detection systems conduct electrical current which changes according to changes in the surrounding magnetic field. Since metal causes a flux in the magnetic field a corresponding change occurs in the electrical current that is reflected back to the detector.
These devices consist of a detector wand connected to a wire. Usually, the exit wand is buried underneath the driveway. The wire defines a radius of placement for the wand. A typical range of detection for the wand is approximately twelve feet. The wand senses metal objects that move into its detection field and then triggers the gate's motor. Manufacturers suggest testing your unit by placing it on the ground and pointing it in the direction of the driveway and driving a vehicle into its detection field.
Loop detectors may consist of a wire buried under the driveway that detects metal objects passing over it. They are termed loop detectors because of their ovular shape. The loops are usually buried a few inches beneath the driveway surface. If your gates are made of metal the loop's edge should be placed at least three feet away from the gate's path as the loop may mistake the gate for a passing vehicle.
However, depending on your particular needs and driveway dimensions, you may connect multiple loops to a single detection unit. One of the most important matters to remember about loop detectors is to ensure that they are not affected by weather. They must be buried so that groundwater seepage does not affect them.
Driveway Gate Sensing Edges
These devices are placed along the edges of doors and gates. The edges may be connected to a secondary relay that triggers the motor or they may be connected to the motor's relay themselves. When they detect a foreign object in the path of a closing door or gate, they automatically trigger the relay to reverse the door's or the gate's direction and prevent serious damage and injury.