GB1378280A - Radio detector for detecting the movement of people or objects in a confined space - Google Patents

Radio detector for detecting the movement of people or objects in a confined space

Info

Publication number
GB1378280A
GB1378280A GB1151673A GB1151673A GB1378280A GB 1378280 A GB1378280 A GB 1378280A GB 1151673 A GB1151673 A GB 1151673A GB 1151673 A GB1151673 A GB 1151673A GB 1378280 A GB1378280 A GB 1378280A
Authority
GB
United Kingdom
Prior art keywords
amplifier
antenna
oscillator
feedback
circuit
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.)
Expired
Application number
GB1151673A
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.)
Salmet G R
Original Assignee
Salmet G R
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 Salmet G R filed Critical Salmet G R
Publication of GB1378280A publication Critical patent/GB1378280A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
    • G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
    • G01V3/10—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils
    • G01V3/101—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils by measuring the impedance of the search coil; by measuring features of a resonant circuit comprising the search coil
    • G01V3/102—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils by measuring the impedance of the search coil; by measuring features of a resonant circuit comprising the search coil by measuring amplitude
    • 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

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Remote Sensing (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geology (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geophysics (AREA)
  • Burglar Alarm Systems (AREA)
  • Transmitters (AREA)

Abstract

1378280 Proximity switching systems G R SALMET 9 March 1973 [21 March 1972] 11516/73 Heading G1N The invention relates to a system wherein the movement of a person or article in the vicinity of an antenna A, varies the tuning of a transmitter coil L energized from an amplifier A1 fed from an oscillator supply O. FEEDBACK from the transmitter coil is arranged to vary the oscillator frequency slightly in a direction to enhance the detuning effect of the body on the transmitter coil. (see "details" overleaf). Applications security monitoring to detect intruders, opening of (metal) safe-doors, controlling advertising display and taped information, automatic door opening, timed passage-way lighting control, counting passers. Additional features:- (i) a differentiating circuit C 3 R 3 in the detector section avoids slow drift effects. (ii) an integrating network with a timeconstant of e.g. 0À5 secs. in amplifier A2 provides noise interference suppression. (iii) a stick-circuit may be provided by applying bias to amplifier A2 over one of the alarm relay contacts K2. (iv) alternatively a holding delay may be provided by a series resistor in the D.C. supply to the detector, so that when the amplifier A2 draws increased current to operate the relay a drop of e.g. 5 volts occurs in the supply and thus applies a 5 volt signal to the differentiating capacitor C 3 which maintains the alarm signal until it has leaked away through R 3 . Details. Fig.7 shows a Hartley transistor oscillator section TR 1 feeding through an amplifier section TR 2 to the antenna circuit L, C 1 . Feedback is transmitted through capacitor C6 to the end g of the oscillator coil for detuning in a sense to enhance the effect of antenna capacity increase due to an intruder alternatively feedback to tapping g<SP>1</SP> on the opposite side of the ground tapping h is used for a decrease in antenna capacity e.g. as in opening of a safe door (and the antenna circuit is tuned, of course, the opposite flank of the resonant peak).
GB1151673A 1972-03-21 1973-03-09 Radio detector for detecting the movement of people or objects in a confined space Expired GB1378280A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7209800A FR2176499B1 (en) 1972-03-21 1972-03-21

Publications (1)

Publication Number Publication Date
GB1378280A true GB1378280A (en) 1974-12-27

Family

ID=9095554

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1151673A Expired GB1378280A (en) 1972-03-21 1973-03-09 Radio detector for detecting the movement of people or objects in a confined space

Country Status (4)

Country Link
US (1) US3828335A (en)
DE (1) DE2312484A1 (en)
FR (1) FR2176499B1 (en)
GB (1) GB1378280A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2175397A (en) * 1983-11-22 1986-11-26 Honda Motor Co Ltd Devices for detecting objects
GB2455540A (en) * 2007-12-13 2009-06-17 Philip Hodgetts Proximity sensing system to control electricity supply

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1093655A (en) * 1977-01-19 1981-01-13 Martin T. Cole Intrusion or movement detector
US4325058A (en) * 1980-06-11 1982-04-13 Gentex Corporation Pre-intrusion detection and alarm system
US4380721A (en) * 1980-12-29 1983-04-19 Bullock John W Proximity switch
MY122034A (en) * 1996-09-27 2006-03-31 Inventio Ag Identification system for an elevator installation
JP3409752B2 (en) * 1999-10-26 2003-05-26 トヨタ自動車株式会社 Moving object detection device, abnormality alarm device and loading room opening control device
AU2008353278A1 (en) * 2008-03-17 2009-09-24 Powermat Technologies Ltd. Inductive transmission system
US8981598B2 (en) 2008-07-02 2015-03-17 Powermat Technologies Ltd. Energy efficient inductive power transmission system and method
US11979201B2 (en) 2008-07-02 2024-05-07 Powermat Technologies Ltd. System and method for coded communication signals regulating inductive power transmissions
ES2534702B1 (en) * 2013-09-24 2016-02-09 Ontech Security, Sl ELECTROSTATIC FIELD SENSOR AND SECURITY SYSTEM IN INTERIOR SPACES
US10511347B2 (en) * 2017-11-14 2019-12-17 Nxp B.V. Device detection in contactless communication systems

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2152296A (en) * 1936-09-21 1939-03-28 Talking Advertising Corp Advertising device
DE970232C (en) * 1937-05-01 1958-08-28 Emi Ltd Arrangement for coupling a high frequency source to a consumer
US3005191A (en) * 1957-07-10 1961-10-17 Mosler Res Products Inc Security alarm system
US2992420A (en) * 1957-11-08 1961-07-11 Holmes Electric Protective Com Capacity type burglar alarm systems
US3324647A (en) * 1964-08-11 1967-06-13 Parmet Company Proximity detector
DE1566723A1 (en) * 1967-04-13 1970-08-06 Johannes Rode Room surveillance system
US3573783A (en) * 1967-09-13 1971-04-06 R F Controls Inc Proximity sensor
US3495353A (en) * 1968-09-23 1970-02-17 Stanley Works Door operating mechanism

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2175397A (en) * 1983-11-22 1986-11-26 Honda Motor Co Ltd Devices for detecting objects
GB2175397B (en) * 1983-11-22 1990-01-17 Honda Motor Co Ltd Devices for detecting objects
GB2455540A (en) * 2007-12-13 2009-06-17 Philip Hodgetts Proximity sensing system to control electricity supply

Also Published As

Publication number Publication date
FR2176499A1 (en) 1973-11-02
US3828335A (en) 1974-08-06
FR2176499B1 (en) 1975-03-21
DE2312484A1 (en) 1973-10-04

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Legal Events

Date Code Title Description
PS Patent sealed [section 19, patents act 1949]
PLNP Patent lapsed through nonpayment of renewal fees