Patent ID: 7345595

Claim:
A driveway vehicle motion detector comprising: a first sensor generating signals by reacting to the fluctuation of the earth's magnetic field caused by a moving vehicle on the driveway and comprising a multiple turn wire coil wound on a core of a first length, with the first sensor located on a sensor line that is oriented at an angle in the range of between 80 degrees and 100 degrees to the orientation of a road; a second sensor generating signals by reacting to the fluctuation of the earth's magnetic field caused by a moving vehicle on the driveway and comprising a multiple turn wire coil wound on a core of a second length that is greater than the first length, with the second sensor located on the sensor line and farther from the road along the sensor line than the first sensor by a spacing distance, with the second sensor oriented to the road and interconnected in series with the first sensor so that the signals generated by the second sensor are of opposite polarity to the signals generated by the first sensor and counteract the signals of the first sensor; and a transmitting means feeding the combined signals generated by the series connected first sensor and second sensor to control circuits.