Classifications

• • G—PHYSICS
  • G08—SIGNALLING
  • G08B—SIGNALLING SYSTEMS, e.g. PERSONAL 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
  • G08B21/084—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 physical movement characteristics of the water

Definitions

• the present invention relates to a device for detecting the fall of a body in a swimming pool, particularly that of a child or an animal. Many children die each year by drowning in a fall in an unattended swimming pool. Existing means such as physical protection barriers are unsightly and do not forget to close or lock the gate behind you after each visit or after each use of the pool. The ideal solution to effectively protect the pool while keeping its cachet would be a device capable of detecting the fall of a body. Unfortunately, it is very difficult to discern the aquatic wave caused by the fall and disturbing elements such as: the wind on the device housing, the waves caused by the wind, the operation of the cleaning robot, the start of the filtration, rain, etc ...
• the invention provides a device for detecting the fall of a body in a swimming pool comprising a probe immersed in the water of the.
• the electronic card is adapted to control, in the event of detection of a fall, a siren inside the housing.
• the electronic card is adapted to control, in the event of detection of a fall, a radio transmitter.
• the pressure sensors are of the piezoelectric type.
• the electronic card comprises a bandpass filter centered on a hertz with a narrow bandwidth, the filter being adapted to reject the signals coming from the filtration of the swimming pool, from the fall of an object such as a balloon, cleaning of the pool by a robot, rain, and a large part of the waves caused by the wind.
• the electronic card includes a microcontroller adapted to reduce the frequency window of the signals processed by a timer counting the interval separating two signals from the pool, the microcontroller rejecting the signals if the period is not included in an interval predetermined
• the electronic card comprises a microcontroller adapted to count the number of valid information.
• the number of successive and non-missing valid pieces of information for detecting a fall is between 2 and 5.
• FIG. 1 schematically represents the embodiment of the device according to the invention.
• the detection device is made up of an emerged box (7) protecting the electronics (4), a probe made up of a plastic tube immersed in the pool water (1) used to transmit the aquatic waves in variations pressure in the first part of the emerged housing (8) serving as a compression chamber. Pressure variations are converted into voltage by the piezoelectric type sensor (2).
• Another similar sensor (3) located in the main compartment of the housing makes it possible, by subtraction on the electronic card (4), to eliminate the vibrations as well as the noise caused by the wind on the housing (7).
• This principle of two identical sensors mounted in differential allows to overcome the problems due to the wind on the case because each paired sensor listens to the same vibration, a simple subtraction makes it possible to listen only to the pressure difference inside the chamber compression (8).
• the location and the direction of the two sensors (2) and (3) are not critical, indeed the sensor (2) can be mounted through the partition separating the compression chamber (8) and the main compartment.
• the electronic card (4) described below controls a siren (6) integrated into the housing (7).
• the card optionally controls a radio transmitter (5) used to control a remote siren.
• FIG. 2 schematically represents the electronic card (4) as well as the various elements which compose it.
• the two sensors (2) and (3) are connected to two impedance adapters (9) making it possible to obtain a very high input impedance at the level of the sensors, moreover their very low impedance output makes it possible to attack a subtractor also called differential amplifier (10).
• This subtractor allows rejection between the disturbances on the box which returns to common mode and the pressure differences in the compression chamber coming from the aquatic waves.
• the output of the subtractor (10) drives a bandpass filter (11), this filter is centered on a hertz with a very narrow bandwidth.
• the output of the filter (11) goes into an adjustable gain amplifier (12), this can be adjusted to be able to best adapt to the basin to be protected, depending on: dimensions, depth, depth d immersion of the probe (1), of the dispersion of the electronic components and of the sensors.
• This amplifier is used to obtain a sufficiently large signal between 1 and 2 volts to be easily interpretable by the microcontroller (13).
• two treatments are carried out inside the microcontroller (13). First treatment: further reduce the frequency window already reduced by the filter (11).
• a timer counts the time interval separating two signals, if the period is too long or too short, the software rejects the information and considers that it may come from the wind over the pool.
• Second treatment as the wind enters our frequency capture domain (because it causes white noise) we count the number of valid information obtained. Indeed, a difference remains between the wind and the signature of the fall: the fall is a cyclic wave that repeats over time, the wind meanwhile is a chaotic noise that sweeps across an entire frequency band, it is not not constant neither in frequency nor in amplitude. The fact of counting a successive number of valid information certainly allows us to differentiate between the fall and the wind. The valid information must be successive and not missing, the number of valid information can vary from two to five.
• three consecutive valid pieces of information is a good compromise between reaction speed and good immunity to waves caused by the wind on the basin. For example, a count on three valid pieces of information only delays us on the triggering of the alarm by approximately three seconds, if the distance between the fall and the alarm detector is 7 meters (approximately 7 seconds the time that the water wave arrives at the probe) 3 seconds of treatment remain, the alarm is triggered in less than 11 seconds, which remains entirely acceptable.
• the microcontroller (13) controls an integrated siren (6) in the housing used to alert the parents.
• a radio transmitter (5) can also optionally control a radio transmitter (5) to control a remote siren.
• Modifications can be made to the description which has just been made without departing from the scope of the invention.
• the amplifier (12) between the subtractor (10) and the filter (11), it works as well.
• the microcontroller (13) could be replaced by a pair of fixed threshold comparators followed by a counter oscillator.

Landscapes

• Emergency Management (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Business, Economics & Management (AREA)
• Emergency Alarm Devices (AREA)
• Arrangements For Transmission Of Measured Signals (AREA)
• Burglar Alarm Systems (AREA)
• Alarm Systems (AREA)
• Manipulator (AREA)
• Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
• Percussion Or Vibration Massage (AREA)
• Geophysics And Detection Of Objects (AREA)
• Telephone Function (AREA)

Applications Claiming Priority (2)

Publications (2)

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Family Applications (1)

Country Status (13)

Families Citing this family (19)

Family Cites Families (6)

• 2004
  • 2004-04-07 FR FR0403625A patent/FR2868861B3/fr not_active Expired - Lifetime
• 2005
  • 2005-04-07 DE DE602005015216T patent/DE602005015216D1/de not_active Expired - Fee Related
  • 2005-04-07 AT AT05753715T patent/ATE435475T1/de not_active IP Right Cessation
  • 2005-04-07 EP EP05753715A patent/EP1756784B1/de not_active Expired - Lifetime
  • 2005-04-07 WO PCT/FR2005/000848 patent/WO2005101343A1/fr not_active Ceased
  • 2005-04-07 RU RU2006138200/09A patent/RU2006138200A/ru not_active Application Discontinuation
  • 2005-04-07 AU AU2005234192A patent/AU2005234192A1/en not_active Abandoned
  • 2005-04-07 US US10/599,733 patent/US7427923B2/en not_active Expired - Lifetime
  • 2005-04-07 CN CNA2005800107582A patent/CN1938733A/zh active Pending
  • 2005-04-07 BR BRPI0509749-5A patent/BRPI0509749A/pt not_active IP Right Cessation
  • 2005-04-07 CA CA002561055A patent/CA2561055A1/fr not_active Abandoned
• 2006
  • 2006-09-28 IL IL178368A patent/IL178368A0/en unknown
  • 2006-10-03 ZA ZA200608213A patent/ZA200608213B/en unknown

Non-Patent Citations (1)

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