Bc Research and Development, Inc.

Spectrum 2000, Inc.

Farrokh Fattahi

Mark A Beran

A presence detecting apparatus and method are disclosed, the apparatus including an emitter array and receiver array configured, oriented and shielded to provide an effective detection area characterized by a truncated elliptical footprint, a background compensation network for automatically compensating for variations in environmental conditions in the detection area to provide a substantially constant detection sensitivity, and discriminating circuitry for discriminating signals indicative of a body in the detection area from transient and steady state signals. The emitter circuits and receiving and detecting circuits are capable of asynchronous operation, and the receiver array and detector array are housed so that the receiver array is substantially isolated from selected electromagnetic signals from the detector array.

Presence detecting apparatus and method for automatic doors

A system is described for monitoring moisture level in soil and controlling the application of water to the soil or other growing media. The system includes at least one sensing unit which is disposed in the soil and is adapted to periodically monitor moisture content in the soil. The sensing unit is powered by low voltage, low current, alternating current having a frequency in the range of 1.0 to 10 KHz and utilizes a square wave with fifty percent duty cycle. A control means is electrically connected to the sensing unit and is adapted to (a) compare the moisture content in the soil to a preset moisture requirement, and (b) control the application of water to the soil.

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Boulder, CO, United States of America

Farrokh Fattahi