Proximity sensors or detectors of the foregoing type typically use radio frequency (RF) or infrared (IR) transmitters and receivers facing in a common direction so that RF or IR energy emitted by the transmitter is reflected back to the receiver when an object is present proximate the detector. Conventional systems of this type relying on energy from the source being reflected back to the receiver and measured then compare that measurement, either analog or digital, to a reference value. The results of that comparison are then used to determine if an object is within the detector's range or not. In some designs the reference value is altered slightly and the measurements repeated in an attempt to ensure that there is indeed an object present.
The infrared and RF spectrums are becoming quite noisy with either intentional or unintentional radiators. These signals can interfere with existing detection systems and cause false interpretations. That is, a signal received by the receiver from an energy source outside the detector may be interpreted by the detector as a reflection of energy emitted by the transmitter, resulting in a false-positive reading indicative of the presence of an object proximate the detector when in fact no such object is present.
It is therefore desirable to provide a proximity detector that minimizes the chances of a random detection. Applicant has developed the system and method detailed herein below to more reliably detect an object regardless of the extraneous signals from other sources and changing ambient conditions.