Lighting control system and method
First Claim
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1. A lighting system for a space comprising:
- (a) a source of illumination for the space;
(b) a control circuit for said source of illumination;
(c) means for radiating electromagnetic energy at a predetermined ultrasonic frequency and at a generally constant amplitude into the space to be monitored;
(d) means for detecting electromagnetic energy reflected from the objects in the space, said energy being in the form of the radiated ultrasonic energy modulated by a signal representing any motion within the space, said means providing a first signal;
(e) means for automatically adjusting the amplitude of said first signal to within predetermined limits;
(f) means for filtering out the frequency components of the amplitude adjusted first signal other than the predetermined frequency; and
(g) means for detecting variations in the amplitude of said first signal in excess of said predetermined limit to generate a control signal in response thereto to energize and deenergize said illumination control circuit.
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Abstract
A lighting control circuit responsive to amplitude variations related to the effects of movement on the reflection of electromagnetic energy at an ultrasonic frequency.
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Citations
9 Claims
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1. A lighting system for a space comprising:
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(a) a source of illumination for the space; (b) a control circuit for said source of illumination; (c) means for radiating electromagnetic energy at a predetermined ultrasonic frequency and at a generally constant amplitude into the space to be monitored; (d) means for detecting electromagnetic energy reflected from the objects in the space, said energy being in the form of the radiated ultrasonic energy modulated by a signal representing any motion within the space, said means providing a first signal; (e) means for automatically adjusting the amplitude of said first signal to within predetermined limits; (f) means for filtering out the frequency components of the amplitude adjusted first signal other than the predetermined frequency; and (g) means for detecting variations in the amplitude of said first signal in excess of said predetermined limit to generate a control signal in response thereto to energize and deenergize said illumination control circuit. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of controling a lighting circuit for a space comprising the steps of:
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(a) radiating electromagnetic energy into a space at a predetermined ultrasonic frequency and generally constant amplitude; (b) detecting electromagnetic reflected from the space to provide a first signal; (c) automatically adjusting the amplitude of said first signal to within predetermined limits; (d) filtering out frequency components of the amplitude adjusted first signal other then the predetermined fequency; (e) detecting amplitude excursions in excess of a predetermined limit to provide a reset signal and a first control signal; (f) enabling a timing circuit responsively to each reset signal; (g) applying the first control signal to the lighting circuit to effect the energization thereof; (h) generating a second lighting circuit control signal responsively to the absense of a reset signal within a predetermined time period following each reset signal; and - View Dependent Claims (9)
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8. (i) applying the second control signal to the lighting circuit to effect the denergization thereof.
Specification