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GB2228574A - Proximity sensor - Google Patents

Proximity sensor

Info

Publication number
GB2228574A
GB2228574A GB9005972A GB9005972A GB2228574A GB 2228574 A GB2228574 A GB 2228574A GB 9005972 A GB9005972 A GB 9005972A GB 9005972 A GB9005972 A GB 9005972A GB 2228574 A GB2228574 A GB 2228574A
Authority
GB
United Kingdom
Prior art keywords
sensing element
sensor
disturbance
change
effective time
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.)
Withdrawn
Application number
GB9005972A
Other versions
GB9005972D0 (en
Inventor
Anatol Tirkel
Geoffrey Lewis Kidd
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.)
SIMPSON ROLAND B
Original Assignee
SIMPSON ROLAND B
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 SIMPSON ROLAND B filed Critical SIMPSON ROLAND B
Publication of GB9005972D0 publication Critical patent/GB9005972D0/en
Publication of GB2228574A publication Critical patent/GB2228574A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
    • G08B29/18—Prevention or correction of operating errors
    • G08B29/20—Calibration, including self-calibrating arrangements
    • G08B29/24—Self-calibration, e.g. compensating for environmental drift or ageing of components
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/22—Electrical actuation
    • G08B13/26—Electrical actuation by proximity of an intruder causing variation in capacitance or inductance of a circuit
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
    • G08B29/18—Prevention or correction of operating errors
    • G08B29/185—Signal analysis techniques for reducing or preventing false alarms or for enhancing the reliability of the system

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Electronic Switches (AREA)
  • Push-Button Switches (AREA)
  • Switches That Are Operated By Magnetic Or Electric Fields (AREA)
  • Geophysics And Detection Of Objects (AREA)

Abstract

A proximity sensor that employs an electrostatic sensing element (30) driven by an oscillator (26) is described, in which a disturbance of the electromagnetic field surrounding the sensing element is sensed by detecting small variations in the effective capacitance of the sensing element. An artificial disturbance of the field, of the kind the sensor is designed to sense, is discriminated from natural disturbances, of the kind caused by environmental drift, by measuring the effective time rates of change of said disturbance and comparing the measured value to an alarm threshold value. A microprocessor based control device (22) is employed to measure the effective time rates of change of the digital signal , representative of the detected capacitance variations of the sensing element (30), and to provide other control functions for the sensor, such as calibration on start-up and periodic recalibration during normal operation. The sensing element (30) is provided with an interface (28) in the form of a tuned circuit which is maintained near resonance by a voltage controlled capacitor (32). Maximum sensitivity of the sensor to capacitance variations of the sensing element (30) is maintained using a programmable voltage source (34) under the direct control of processor (22). Processor (22) employs a cascade of digital Finite Impulse Response (FIR) filters (48), configured as low-pass filters, to measure the effective time rates of change of the digital signal. A security sensing system is also described in which a plurality of the proximity sensors are controlled by a monitor using an RF communications link.
GB9005972A 1987-09-16 1990-03-14 Proximity sensor Withdrawn GB2228574A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AUPI442487 1987-09-16
PCT/AU1988/000363 WO1989002635A1 (en) 1987-09-16 1988-09-16 Proximity sensor

Publications (2)

Publication Number Publication Date
GB9005972D0 GB9005972D0 (en) 1990-05-23
GB2228574A true GB2228574A (en) 1990-08-29

Family

ID=3772460

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9005972A Withdrawn GB2228574A (en) 1987-09-16 1990-03-14 Proximity sensor

Country Status (3)

Country Link
AU (1) AU2481088A (en)
GB (1) GB2228574A (en)
WO (1) WO1989002635A1 (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2284891A (en) * 1993-12-15 1995-06-21 Michael John Hutchings Particle detection apparatus
GB2291204A (en) * 1994-07-08 1996-01-17 Seikosha Kk Object sensing apparatus
GB2294606A (en) * 1994-10-19 1996-05-01 Benny Bahman Elmi Television Proximity Detector
GB2353097A (en) * 1999-07-23 2001-02-14 Hampden Smith David Eric Hidden electrical switch
GB2368126A (en) * 2000-10-19 2002-04-24 Hampden Smith David Eric Modular sensor switch
CN110120140A (en) * 2019-04-16 2019-08-13 电子科技大学 A kind of fusion capacitor disturbing signal and the combined type of vision signal enclose boundary's alarm method

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2134930A1 (en) * 1993-11-18 1995-05-19 Charles Gerston Body detector
US6067019A (en) * 1996-11-25 2000-05-23 Hill-Rom, Inc. Bed exit detection apparatus
US5808552A (en) * 1996-11-25 1998-09-15 Hill-Rom, Inc. Patient detection system for a patient-support device
US6133837A (en) * 1999-03-05 2000-10-17 Hill-Rom, Inc. Patient position system and method for a support surface
EP1357510A1 (en) * 2002-04-23 2003-10-29 Sony Ericsson Mobile Communications AB Pointing device enabling means, input device and portable device incorporting same
US7495652B2 (en) 2002-04-23 2009-02-24 Sony Ericsson Mobile Communications Ab Pointing device enabling means, input device and portable device incorporating same
US7569762B2 (en) 2006-02-02 2009-08-04 Xpresense Llc RF-based dynamic remote control for audio effects devices or the like
PT2290391T (en) 2009-09-01 2021-03-12 G4S Monitoring Tech Limited Proximity sensors
US20120169499A1 (en) * 2010-12-31 2012-07-05 Schneider Electric Buildings Ab Method and system for monitoring physical security via detecting potential intrusion

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4016529A (en) * 1974-05-01 1977-04-05 Canon Kabushiki Kaisha Body detecting device
US4063447A (en) * 1977-03-14 1977-12-20 Honeywell, Inc. Bridge circuit with drift compensation
AU5344079A (en) * 1978-12-05 1980-06-12 Societe Anonyme Trefilunion Compensating drift in alarm system bridge circuit
US4602246A (en) * 1982-02-11 1986-07-22 Jensen Garold K Intruder detector apparatus
DE3526341A1 (en) * 1985-07-23 1987-01-29 Siemens Ag Method and device for accurately evaluating the measurement signals determined from a capacitive protective fence
US4721945A (en) * 1984-11-19 1988-01-26 501 Control Data Canada Limited Simulated targets for detection systems

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4016529A (en) * 1974-05-01 1977-04-05 Canon Kabushiki Kaisha Body detecting device
US4063447A (en) * 1977-03-14 1977-12-20 Honeywell, Inc. Bridge circuit with drift compensation
AU5344079A (en) * 1978-12-05 1980-06-12 Societe Anonyme Trefilunion Compensating drift in alarm system bridge circuit
US4602246A (en) * 1982-02-11 1986-07-22 Jensen Garold K Intruder detector apparatus
US4721945A (en) * 1984-11-19 1988-01-26 501 Control Data Canada Limited Simulated targets for detection systems
DE3526341A1 (en) * 1985-07-23 1987-01-29 Siemens Ag Method and device for accurately evaluating the measurement signals determined from a capacitive protective fence

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2284891A (en) * 1993-12-15 1995-06-21 Michael John Hutchings Particle detection apparatus
GB2284891B (en) * 1993-12-15 1997-08-27 Michael John Hutchings Particle detection apparatus
GB2291204A (en) * 1994-07-08 1996-01-17 Seikosha Kk Object sensing apparatus
GB2294606A (en) * 1994-10-19 1996-05-01 Benny Bahman Elmi Television Proximity Detector
GB2294606B (en) * 1994-10-19 1999-05-19 Benny Bahman Elmi Motion Detector
GB2353097A (en) * 1999-07-23 2001-02-14 Hampden Smith David Eric Hidden electrical switch
GB2368126A (en) * 2000-10-19 2002-04-24 Hampden Smith David Eric Modular sensor switch
CN110120140A (en) * 2019-04-16 2019-08-13 电子科技大学 A kind of fusion capacitor disturbing signal and the combined type of vision signal enclose boundary's alarm method
CN110120140B (en) * 2019-04-16 2020-12-29 电子科技大学 Combined type enclosure alarm method fusing capacitance disturbance signal and video signal

Also Published As

Publication number Publication date
AU2481088A (en) 1989-04-17
WO1989002635A1 (en) 1989-03-23
GB9005972D0 (en) 1990-05-23

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Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)