Infrared detection switching circuit

Details Infrared detection switching circuit Infrared detection switching circuit

1994-02-24

1995-05-09

Hannaher, Constantine

Radiant energy

Invisible radiant energy responsive electric signalling

Infrared responsive

250342, 250DIG1, G01J 534

Patent

active

054142636

ABSTRACT:
A passive infrared detection and conversion circuit includes a pyrosensor, a current amplifier, a capacitor, and a signal processor circuit. The signal processor is operable to charge the capacitor to a first voltage level and to measure a capacitor discharge time, the time required for the capacitor to discharge from the first voltage level to a second voltage level. The signal processor is further operable to generate an electrical control signal responsive to a variation in the capacitor discharge time which corresponds to a significant motion event. When the pyrosensor is exposed to infrared motion, it generates a transient current, and the capacitor discharge time corresponds to the transient current. The signal processor circuit includes logic operable to compare the capacitor discharge time with a long-term average capacitor discharge time. The signal processor circuit generates the electrical control signal only when the capacitor discharge time deviates from the long-term average capacitor discharge time by exceeding a predetermined threshold margin and/or satisfying other timing and/or pulse sequence patterns. The logic of the signal processor circuit may be further operable to calculate and update the long-term average capacitor discharge time based on the capacitor discharge time such that the logic filters out unwanted background signals and component tolerance variations, thereby creating a dynamic threshold system for detecting significant motion.

REFERENCES:
patent: 3914753 (1975-10-01), Cho
patent: 3963919 (1976-06-01), Sells
patent: 3988726 (1976-10-01), Reiss et al.
patent: 4300048 (1981-11-01), Barbier et al.
patent: 4418335 (1983-11-01), Genahr
patent: 4521768 (1985-06-01), Haran et al.
patent: 4618770 (1986-10-01), Maile
patent: 4825079 (1989-04-01), Takamatsu et al.
patent: 4929833 (1990-05-01), Smith
patent: 4943712 (1990-07-01), Wilder
patent: 4952808 (1990-03-01), Turnbull et al.
patent: 5276427 (1994-01-01), Peterson

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