GB2020872A - Ambient Noise Intruder Alarm - Google Patents

Ambient Noise Intruder Alarm

Info

Publication number
GB2020872A
GB2020872A GB7914973A GB7914973A GB2020872A GB 2020872 A GB2020872 A GB 2020872A GB 7914973 A GB7914973 A GB 7914973A GB 7914973 A GB7914973 A GB 7914973A GB 2020872 A GB2020872 A GB 2020872A
Authority
GB
United Kingdom
Prior art keywords
receivers
space
intruder
ambient noise
threshold
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB7914973A
Other versions
GB2020872B (en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to GB7914973A priority Critical patent/GB2020872B/en
Publication of GB2020872A publication Critical patent/GB2020872A/en
Application granted granted Critical
Publication of GB2020872B publication Critical patent/GB2020872B/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/16—Actuation by interference with mechanical vibrations in air or other fluid
    • G08B13/1654—Actuation by interference with mechanical vibrations in air or other fluid using passive vibration detection systems
    • G08B13/1672—Actuation by interference with mechanical vibrations in air or other fluid using passive vibration detection systems using sonic detecting means, e.g. a microphone operating in the audio frequency range

Abstract

An intruder alarm apparatus which does not consume considerable energy during the watch period and does not depend on itself radiating energy. Two receivers R1 and R2 inside and outside a closed space S are responsive to ambient or environmental noise and a comparator A provides an alarm signal when the difference between the outputs of the two receivers falls below a threshold, indicating that the wall W to the space has been breached as at time T. Alternatively, the two receivers may be spaced apart within the space and the comparator provides the alarm signal when the difference between the two outputs rises above a threshold, indicating that an intruder is present and closer to one receiver than the other. <IMAGE>
GB7914973A 1978-05-15 1979-04-30 Ambient noise intruder alarm Expired GB2020872B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB7914973A GB2020872B (en) 1978-05-15 1979-04-30 Ambient noise intruder alarm

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB1960378 1978-05-15
GB7914973A GB2020872B (en) 1978-05-15 1979-04-30 Ambient noise intruder alarm

Publications (2)

Publication Number Publication Date
GB2020872A true GB2020872A (en) 1979-11-21
GB2020872B GB2020872B (en) 1982-10-13

Family

ID=26254142

Family Applications (1)

Application Number Title Priority Date Filing Date
GB7914973A Expired GB2020872B (en) 1978-05-15 1979-04-30 Ambient noise intruder alarm

Country Status (1)

Country Link
GB (1) GB2020872B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2183037A (en) * 1985-11-14 1987-05-28 Rolls Royce Acoustic sensor systems for controlling processes or machines
FR2596179A1 (en) * 1986-03-18 1987-09-25 Smcm Intruder detection system, applicable especially to an alarm system
US4760295A (en) * 1985-04-17 1988-07-26 Geoquip Security Systems Ltd. Vibration-sensitive transducer

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4760295A (en) * 1985-04-17 1988-07-26 Geoquip Security Systems Ltd. Vibration-sensitive transducer
GB2183037A (en) * 1985-11-14 1987-05-28 Rolls Royce Acoustic sensor systems for controlling processes or machines
GB2183037B (en) * 1985-11-14 1989-12-13 Rolls Royce Sensors for controlling processes or machines
FR2596179A1 (en) * 1986-03-18 1987-09-25 Smcm Intruder detection system, applicable especially to an alarm system

Also Published As

Publication number Publication date
GB2020872B (en) 1982-10-13

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee