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US 4,450,437 AGranted
Motion alarm system
AssigneeTechne Electronics, Ltd.
InventorEugene Y. Ho
Life of this patent
Estimating the term…
Abstract
A motion alarm system including a motion detector which provides a motion signal. A signal level detector for detecting the motion signal and providing an output signal when the motion signal exceeds a selected level, and an alarm circuit providing an alarm if the motion signal does not exceed the selected level for a predetermined time.
Claims6
A system for providing an alarm when motion is not sensed comprising
- a motion detecting means for providing
- a motion signal whose amplitude varies with motion
- a level detector connected to receive said output motion signal and provide an output signal when the amplitude of said motion signal is greater than a first amplitude or less than a second amplitude
- means for receiving the level detector output signal and generating a voltage whose amplitude decreases in the absence of a level detector output signal and means responsive to said voltage for providing an alarm signal when the voltage decreases to a predetermined level due to the absence of a level detector output signal for a predetermined time.
1 more element
A system for providing an alarm when motion is not sensed comprising
- a motion detecting means for providing a motion signal whose amplitude varies with motion
- a level detector connected to receive said motion signal and provide an output signal when the amplitude of said motion signal is greater than a first amplitude or less than a second amplitude.
- a charging circuit adapted to control the charge on a capacitor responsive to the level detector output signal whereby to control the voltage across said capacitor
- first means connected to sense the voltage across said capacitor and provide a warning signal when the voltage attains a first voltage level and
- second means connected to sense the voltage across said capacitor and provide an alarm signal when the voltage attains a second voltage level.
2 more elements
Dependencies are inferred from the claim text.