Communications: electrical – Condition responsive indicating system – Specific condition
Patent
1983-06-09
1986-04-15
Rowland, James L.
Communications: electrical
Condition responsive indicating system
Specific condition
340556, 340600, G08B 1308
Patent
active
045830827
ABSTRACT:
Method and apparatus for monitoring the opening and closing of a door and for detecting unauthorized opening of the door. The apparatus comprises a light emitting diode and a sensor mounted with respect to the door so as to be in optical communication with one another when the door is closed. A microprocessor monitors and controls the operation of the light emitting diode and sensor. When the sensor is receiving light, preliminarily indicating that the door is closed, the microprocessor verifies that the light emitting diode and sensor are still in optical communication with one another. In the preferred embodiment verification is achieved by causing the light emitting diode to emit a predetermined sequence of pulses and monitoring whether the sensor tracks the predetermined sequence of pulses. An alarm signal is provided when the sensor senses light and the microprocessor determines that the light emitting diode and sensor are not in optical communication with one another.
REFERENCES:
patent: 3509359 (1970-04-01), Embling
patent: 3924253 (1975-12-01), Marino
patent: 4074246 (1978-02-01), Conklin et al.
patent: 4242670 (1980-12-01), Smith
patent: 4262284 (1981-04-01), Stieff et al.
patent: 4379289 (1983-04-01), Peek
patent: 4458146 (1984-07-01), Reiner et al.
patent: 4465998 (1984-08-01), Durand
IGT
Rowland James L.
Tumm Brian R.
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