US3273138A - Swimming pool monitor - Google Patents

Swimming pool monitor Download PDF

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Publication number
US3273138A
US3273138A US363206A US36320664A US3273138A US 3273138 A US3273138 A US 3273138A US 363206 A US363206 A US 363206A US 36320664 A US36320664 A US 36320664A US 3273138 A US3273138 A US 3273138A
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United States
Prior art keywords
switch
transistor
pool
monitor
signals
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Expired - Lifetime
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US363206A
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English (en)
Inventor
Eric A Kolm
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Sonus Corp
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Sonus Corp
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Publication date
Application filed by Sonus Corp filed Critical Sonus Corp
Priority to US363206A priority Critical patent/US3273138A/en
Priority to CH590365A priority patent/CH459007A/de
Priority to DE19651559253 priority patent/DE1559253A1/de
Priority to GB17948/65A priority patent/GB1033458A/en
Application granted granted Critical
Publication of US3273138A publication Critical patent/US3273138A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B21/00—Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
    • G08B21/02—Alarms for ensuring the safety of persons
    • G08B21/08—Alarms for ensuring the safety of persons responsive to the presence of persons in a body of water, e.g. a swimming pool; responsive to an abnormal condition of a body of water
    • G08B21/082—Alarms for ensuring the safety of persons responsive to the presence of persons in a body of water, e.g. a swimming pool; responsive to an abnormal condition of a body of water by monitoring electrical characteristics of the water
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04H—BUILDINGS OR LIKE STRUCTURES FOR PARTICULAR PURPOSES; SWIMMING OR SPLASH BATHS OR POOLS; MASTS; FENCING; TENTS OR CANOPIES, IN GENERAL
    • E04H4/00—Swimming or splash baths or pools
    • E04H4/06—Safety devices; Coverings for baths

Definitions

  • This invention relates to a swimming pool monitor. It relates more particularly to a swimming pool monitor capable of detecting sounds and turbulence caused by children or animals jumping or falling into an unattended swimming pool and giving a warning signal in response thereto. In addition, the monitor permits someone at a remote location to actually listen to the goings on at the pool and thereby determine the nature of the disturbance and extent of the emergency.
  • prior systems are often unable to discriminate between turbulence in the pool caused by wind, rain, falling twigs, etc., and turbulence produced by struggling children and animals. As a result the pool owner may be subjected to a considerable number of false alarms. If the sensitivity of the alarm is reduced, it may fail to register a true emergency.
  • the main object of this invention is to provide a swimming pool monitor capable of giving an immediate warning signal whenever an object enters intentionally or inadvertently an unattended swimming 001.
  • a further object of this invention is to provide a swimming pool monitor which, after sounding an alarm can be used to listen to the disturbance so that the pool owner can ascertain exactly what is happening by the sounds emanating from, in and around the swimming pool.
  • accidents can actually be prevented. For example, by operating the monitor in the listening mode, a mother can detect potential danger resulting from rough play in or near the pool without ever having to be physically present.
  • a still further object of this invention is to provide a swimming pool monitor which substantially eliminates false alarms because it is nonresponsive to most spurious sounds and vibrations in and around the pool.
  • my swimming pool monitor employs an underwater microphone or hydrophone 10 capable of 3,273,138 Patented Sept. 13, 1966 being submerged in the swimming pool and picking up underwater vibrations. These vibrations may be caused by children or animals thrashing in the water or even by voices or other noises in and around the pool.
  • the output of the hydrophone is coupled through a filter-preamplifier 12 and fed to a detector circuit 14 which senses the amplified signals.
  • the detector circuit 14 actuates a switch energizing an oscillator-amplifier 18 circuit and the latter produces an audible alarm via an associated speaker 20. The alarm will continue until the detector circuit is manually reset by the pool owner, even though the initiating vibrations in the pool cease.
  • the swimming pool monitor also has provision for switching from the aforesaid alarm or warning mode to a listening mode whereby the amplified signals from the hydrophone 10 are caused to bypass the detector circuit 14 and are connected directly to the oscillator-amplifier circuit 18.
  • the circuit 18 amplifies the input signal and feeds it directly to loud speaker 20.
  • Filter circuits are provided in the preamplifier stage 12 of the monitor to shape the frequency response thereof depending on whether the monitor is in the alarm or listening mode.
  • the preamplifier 12 passes the full voice range of frequencies.
  • high frequencies caused by sirens, whistles, etc. and low frequencies caused by thunder, traffic, etc. are filtered out so that the monitor is made less susceptible to false alarms.
  • a sensitivity control compensates for the ambient background noise level that may be present around a given pool installation.
  • the invention is embodied in a simple unit which may be installed with a minimum of effort and powered by a conventional power supply indicated at 21 connected to the standard volt A.C. house supply or, alternatively by batteries.
  • hydrophone 10 is preferably one of the piezoelectric variety capable of producing electrical signals in response to sound vibrations impinging the transducer.
  • the hydrophone 10 is adapted to be submerged in the swimming pool and supported below the water and away from the side of the pool by a bracket (not shown) attached to the side of the pool.
  • a shielded coaxial cable 22 connects the transducer 10 with the filterpreamplifier 12 which is mounted along with the other elements of the monitor within a single cabinet conveniently located in the home of the pool owner.
  • the filter-preamplifier 12 has three transistor stages comprising three similar n-p-n transistors 24, 26 and 28. These transistors are connected in the common-emitter configuration and have bypassed emitter resistors. The collectors 30, 32 and 34 of the transistors are connected through resistors 36, 38 and 430, respectively, to power supply 21.
  • Resistor 38 is preferably a potentiometer having an adjustable center tap 42 whose adjustment controls the gain of the preamplifier 12. Specifically, the potentiometer 38 provides a means for controlling the sensitivity of filter preamplifier 12 so that the system responds only to those signals produced by sounds above the ambient or "background noise level in the vicinity of the pool.
  • a coupling capacitor 44 and series resistance 46 are connected between the inner conductor of coaxial cable 22 and the base 48 of transistor 24.
  • the outer conductor or sheath of cable 22 is grounded.
  • a relatively small coupling capacitor 50 is connected between collector 30 of transistor 24 and the base input 52 of transistor 26.
  • a single pole switch 54a and a relatively large capacitor 56 in series therewith are connected in parallel with capacitor 50.
  • Switch 54:: is movable between two positions, A and 'L. When switch 54a is in the A position, the relatively large capacitor 56 is connected in parallel with the small capacitor 50. In the L position the branch containing the large capacitor 56 is open-circuited and the coupling between transistors 24 and 26 is entirely through the small capacitor 50.
  • a two-position switch 54b has its common terminal connected to the center tap 42 of potentiometer 38.
  • Switch 54b operates between two positions or terminals, A and L.
  • a relatively large capacitor 58 is connected between the L terminal of switch 541) and the base 60 of transistor 28.
  • a smaller capacitor 62 is connected between the A terminal and the base 60.
  • a capacitor 64 is connected between the A terminal of switch 54b and ground.
  • the switches 54a and 54b are ganged together and thus operate in unison.
  • the capacitor 64 and the series resistances associated therewith operate as a low-pass filter reducing electrical signals caused by high frequency background sounds such as whistles, high-pitched squeals, etc. picked up by transducer 10.
  • the circuit parameters of filter preamplifier 12 are selected so that the amplifier passes signals in a band of about 500-900 cycles extending upwardly from approximately 2500 cps.
  • the filter preamplifier 12 has a bandwidth of approximately 500-900 cycles. This particular frequency range has been found to include most of the sounds produced by a person or animal thrashing or struggling in water as well as those sounds caused by a person choking or gasping underwater, but to exclude most of the usual background sounds and noises which have nothing to do with the pool and which tend only to cause false alarms.
  • the electric signals from collector are coupled through a relatively large capacitance, consisting primarily of capacitor 56, to the base 52 of transistor 26. Also, the output of transistor 26 taken from collector 32 is caused to bypass capacitors 62 and 64 and is coupled through the large capacitor 58 directly to the base 60 of transistor 28. As a result, the pass band of the filter amplifier 12 is increased considerably. The frequencies comprising substantially the entire voice range are then amplified by filter-preamplifier 12.
  • preamplifier 12 taken from the collector 34 of transistor 28, is fed to switch 54c.
  • This switch also has two terminals or positions A and L. The A terminal is connected to the detector circuit 14, while the L terminal is connected to the oscillator-amplifier circuit 18 that will be described more particularly later.
  • the detector circuit 14 comprises a diode 66 coupled to the collector 34 by a DC. blocking capacitor 68.
  • the anode 72 of diode 66 is connected through a DC. blocking capacitor 74 to the base 76 of an n-p-n transistor 78 having a grounded emitter.
  • Resistors 80 and 82 are connected between ground and the cathode 70 and anode 72 respectively, of diode 66 to prevent blocking of the diode by signals rectified thereby.
  • the collector 84 of transistor 78 is connected through a resistor 86 to a positive terminal of power supply 21.
  • a resistor 83 connected between base 76 and ground, forms a voltage divider with a resistor 96 and the resistance of a relay coil 100 to bias the base-emitter junction of the transistor 78 for normal conduction.
  • the collector 84' is connected also through a resistor 88 to the base 90 of a normally cut off, grounded emitter, n-p-n transistor 92.
  • a normally closed switch 94 connects the collector 98 of transistor 92 to the junction of the resistor 96 and the relay coil 100. Constant voltage is assured the detector circuit 14 by a Zencr diode 102 in supply 21.
  • the two transistors 78 and 92 form a flip-flop.
  • the flip-flop In the absence of signals from filter-preamplifier 12, the flip-flop is in the one of its stable states in which the transistor 78 is conducting and transistor 92 is cut off by the essentially zero potential of the base 90 resulting from the low collector-emitter resistance in the transistor 78. Thus, substantially no current flows through relay coil 1%.
  • the diode 66 passes only the negative-going portions of the signals to the base input 76 of transistor 78. These portions cut off transistor 78, thereby raising the potential at its collector 84. This increased potential is coupled to the base 90 of transistor 92 causing transistor 92 to conduct. As transistor 92 conducts, the potential at its collector 98 reduces substantially to zero. This reduced potential is coupled back to the base input 76 of transistor '79.
  • the flip-flop is now in its other stable state. The diode 66 prevents positive going portions of signals from reaching the base 76 and thereby returning the flip-flop to its initial state. Consequently the flip-flop remains in its new state, even after the input signals from filter-preamplifier 12 cease.
  • the relay switch 100a is a normally open, single pole switch. It is connected between the A and L terminals of a two-position switch 54d whose common terminal is connected to the power supply 21.
  • the L terminal of switch 54d is connected also through a resistor 108 to the collector 110 of an n-p-n transistor 112.
  • Transistor 112 is connected in the common emitter configuration and has a conventional bypassed emitter resistor and stabilizing and biasing resistors of a conventional amplification stage much like those in filter-preamplifier 12.
  • a coupling capacitor 114 is connected between the L terminal of switch 54c and base 116 of transistor 112.
  • switch 540 When switch 540 is in the L position, the signals from filter-preamplifier 12 bypass the detector circuit 14 and are coupled directly to the base input 116 of transistor 112. However, when switch 540 is in the A position, no signals are fed to the base of transistor 112.
  • switch 54d and relay switch 100a control the power applied to transistor 112.
  • switch 54d When switch 54d is in the A position, power is applied to transistor 1112 only when relay switch 100a is closed by the energizing of coil 100 in the detector circuit 14. But when switch 54d is in the L position, the relay switch 10001 is bypassed and the voltage from power supply 21 is applied directly to transistor 112 independently of the state of the detector circuit 14.
  • Transistor 122 has its emitter 124 connected through a resistor 126 to the power supply 21.
  • An A.C. path to ground is provided the emitter 124 through a capacitor 127.
  • Resistors 128 and 130 in series between the power supply 21 and ground, form a voltage divider biasing the emitter 124 positive with respect to the base 120.
  • the primary winding of an output transformer 132 is connected between ground and the collector 134 of transistor 122.
  • the transformer secondary is connected to speaker 20.
  • a capacitor 136 is connected between collector 134 and the emitter 138 of transistor 112 to provide negative feedback.
  • An R.C. coupling network indicated generally at 140 provides regenerative feedback between the collector 134 of transistor 122 and the base 116 of transistor 112.
  • the feedback network 140 includes a capacitor 142 and a resistor 144 in series therewith, both of which are connected in parallel with a capacitor 146 between collector 134 and the common terminal of a single throw switch 54c.
  • the switch 542 is movable between two terminals A and L, the former of which is connected to the base 116 of transistor 112.
  • the oscillator-amplifier circuit 18 functions as a conventional oscillator by virtue of the network :140. In this mode it can produce an audible whistle or squeal over speaker 20. It cannot oscillate, however, until the relay switch 100a closes to supply power to the first stage transistor 112. This occurs only when current flows in the relay coil 100 in detector circuit 14 pursuant to a change in state of the detector flip-flop circuit as described previously. Once the relay switch 100 closes as aforesaid, the circuit 18 will continue to produce a lound signal over speaker 20 thereby warning the pool owner that someone or something has fallen into or is struggling in the pool. The signal will continue until the relay switch 100a is opened, thereby disabling transistor 112. As mentioned previously, this is brought about by the pool owner or operator momentarily opening the switch 94 in the detector circuit 14.
  • the monitor can also be operated for long periods of time in the listening mode with the switches '54 in the L position. Thus a housewife may listen to children playing in and around the swinmming pool. If the play Of course, the monitor can be used also as a simple means of communicating between the area of the pool and the interior of the home.
  • my swimming pool monitor not only gives a warning alarm when persons approach or enter the swimming pool without authorization, but also enables the homeowner to listen to what is happening at the pool without being physically present there.
  • the homeowner can switch to the listening mode of operation and thereby quickly determine the nature and seriousness of the difiiculty, and be in a much better posit-ion to pro-vide or summon the required assistance.
  • the monitor When the monitor is operating in the alarm mode, its response to sounds in the vicinity of the pool is limited to a relatively narrow band of frequencies which have been found to be particularly indicative of people or animals falling into or struggling in the water. However, when the monitor is operating in its listening mode, its response is altered to permit both high and low frequency sounds to be amplified and reproduced by the speaker 20. Accordingly, the monitor has excellent voice reproduction qualities in its listening mode.
  • a swimming pool monitor comprising an underwater microphone adapted to be submerged in said pool, said microphone producing electric signals in response to sound vibrations in said pool, alarm means, a detector circuit for actuating said alarm means only in response to signals from said microphone, a transducer for reconverting said signals into sound, means including a first switch means connected to pass signals from said microphone alternatively -to said detector circuit and to said transducer, an amplifying circuit connected between said microphone and said first switch means, said amplifying circuit including first and second filter means having wide and narrow pass band respectively, second switch means operative coincidental with said first switch means between two positions to feed the output of said microphone selectively to said first and second filter elements.
  • a swimming pool monitor comprising a first transducer for positioning in the water in said pool, said first transducer producing electric signals in response to sound vibrations in the pool, first amplifier means connected to the output of said transducer, said first amplifier means including switch means operative between two positions so as to feed the output of said first amplifier means selectively to said positions, second amplifier means connected to one position of said switch means, regenerative feedback means in said second amplifier means, said feedback means including a second switch operative coincidentally with said switch so as to disable said feedback circuit when said switch means is in its said one position and to enable said feedback circuit when said switch means is in its other said position, a second transducer connected to the output of said second amplifier means and a detector circuit connected between said other switch means position and said second ampli bomb means, said detector circuit causing said second amplifier means to oscillate only upon arrival of signals from said first transducer.
  • a swimming pool monitor as defined in claim 2 wherein said second amplifier means comprises at least a 'two stage amplifier and means including another switch for providing regenerative feedback in said second amplifier means when said switch means is in said other position.
  • a swimming pool monitor as defined in claim 2 wherein said detector circuit comprises a flip-flop said flip-flop being in one state, control means connected between said flip-flop and said other switch means position for imposing a second state on said flip-flop only in response to signals from said first transducer and thereby actuating said second amplifier means, said flip-flop remaining in said second state even after cessation of said signals and means for returning said flip-flop to its said one state.
  • a swimming pool monitor as defined in claim 6 wherein said -fiip-flop comprises two transistors, one of said transistors being normally conducting, the other of said transistors being normally cut OE, and said control means includes a diode connected between said other switch means position and said one transistor and a relay coil connected in the circuit of said other transistor.

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
  • Alarm Systems (AREA)
  • Emergency Alarm Devices (AREA)
US363206A 1964-04-28 1964-04-28 Swimming pool monitor Expired - Lifetime US3273138A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US363206A US3273138A (en) 1964-04-28 1964-04-28 Swimming pool monitor
CH590365A CH459007A (de) 1964-04-28 1965-04-28 Schwimmbecken-Warnanlage
DE19651559253 DE1559253A1 (de) 1964-04-28 1965-04-28 UEberwachungsgeraet fuer Schwimmbecken
GB17948/65A GB1033458A (en) 1964-04-28 1965-04-28 Improvements in or relating to swimming pool monitors

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US363206A US3273138A (en) 1964-04-28 1964-04-28 Swimming pool monitor

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US3273138A true US3273138A (en) 1966-09-13

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US363206A Expired - Lifetime US3273138A (en) 1964-04-28 1964-04-28 Swimming pool monitor

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CH (1) CH459007A (de)
DE (1) DE1559253A1 (de)
GB (1) GB1033458A (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3810146A (en) * 1972-03-22 1974-05-07 Dworcan M Alarm system for the safety of non-swimmers
US4121200A (en) * 1976-07-22 1978-10-17 Colmenero Gustavo T Swimming pool alarm system
US4187502A (en) * 1977-12-12 1980-02-05 Beverly Frank O Swimming pool alarm system

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6980109B2 (en) 2003-10-30 2005-12-27 Aquasonus, Llc System and method for monitoring intrusion detection in a pool

Citations (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2435996A (en) * 1943-04-01 1948-02-17 Clyde W Baird Detecting and alarm system
US2447156A (en) * 1942-02-23 1948-08-17 Louis B Brittain Radio control system
US2709251A (en) * 1951-08-02 1955-05-24 Kenneth H Schmidt Audio electromagnetic capacity alarm device
US2832915A (en) * 1950-02-03 1958-04-29 Bendix Aviat Corp Alarm system responsive to sonic vibrations
US2942247A (en) * 1956-11-06 1960-06-21 Carl C Lienau Alarm warning system for swimming pools
US2991458A (en) * 1956-07-27 1961-07-04 Cooke Engineering Company Ignition interference alarm
US3041592A (en) * 1957-07-10 1962-06-26 Mosler Res Products Inc Protective alarm system
US3049699A (en) * 1960-01-26 1962-08-14 Howard M Larrick Sound actuated detection and alarm system
US3069673A (en) * 1959-03-18 1962-12-18 Westinghouse Electric Corp Remotely controlled alarm system
US3095730A (en) * 1960-03-02 1963-07-02 Bearing Inspection Inc Apparatus for testing bearings
US3109165A (en) * 1958-09-05 1963-10-29 Specialties Dev Corp Intruder detecting system
GB942848A (en) * 1960-06-30 1963-11-27 Geophysique Cie Gle Improvements in or relating to warning devices
US3128456A (en) * 1957-01-22 1964-04-07 Westinghouse Electric Corp Annunciators with manual reset
US3134790A (en) * 1960-06-11 1964-05-26 Hoechst Ag Cyclopentene derivatives of the androstene, alpha-androstane and beta-androstane series and process for their manufacture
US3147467A (en) * 1961-09-07 1964-09-01 American District Telegraph Co Vibration detection vault alarm system

Patent Citations (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2447156A (en) * 1942-02-23 1948-08-17 Louis B Brittain Radio control system
US2435996A (en) * 1943-04-01 1948-02-17 Clyde W Baird Detecting and alarm system
US2832915A (en) * 1950-02-03 1958-04-29 Bendix Aviat Corp Alarm system responsive to sonic vibrations
US2709251A (en) * 1951-08-02 1955-05-24 Kenneth H Schmidt Audio electromagnetic capacity alarm device
US2991458A (en) * 1956-07-27 1961-07-04 Cooke Engineering Company Ignition interference alarm
US2942247A (en) * 1956-11-06 1960-06-21 Carl C Lienau Alarm warning system for swimming pools
US3128456A (en) * 1957-01-22 1964-04-07 Westinghouse Electric Corp Annunciators with manual reset
US3041592A (en) * 1957-07-10 1962-06-26 Mosler Res Products Inc Protective alarm system
US3109165A (en) * 1958-09-05 1963-10-29 Specialties Dev Corp Intruder detecting system
US3069673A (en) * 1959-03-18 1962-12-18 Westinghouse Electric Corp Remotely controlled alarm system
US3049699A (en) * 1960-01-26 1962-08-14 Howard M Larrick Sound actuated detection and alarm system
US3095730A (en) * 1960-03-02 1963-07-02 Bearing Inspection Inc Apparatus for testing bearings
US3134790A (en) * 1960-06-11 1964-05-26 Hoechst Ag Cyclopentene derivatives of the androstene, alpha-androstane and beta-androstane series and process for their manufacture
GB942848A (en) * 1960-06-30 1963-11-27 Geophysique Cie Gle Improvements in or relating to warning devices
US3147467A (en) * 1961-09-07 1964-09-01 American District Telegraph Co Vibration detection vault alarm system

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3810146A (en) * 1972-03-22 1974-05-07 Dworcan M Alarm system for the safety of non-swimmers
US4121200A (en) * 1976-07-22 1978-10-17 Colmenero Gustavo T Swimming pool alarm system
US4187502A (en) * 1977-12-12 1980-02-05 Beverly Frank O Swimming pool alarm system

Also Published As

Publication number Publication date
CH459007A (de) 1968-06-30
GB1033458A (en) 1966-06-22
DE1559253A1 (de) 1970-02-12

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