GB2343042A

GB2343042A - Pool alarm system

Info

Publication number: GB2343042A
Application number: GB9822831A
Authority: GB
Inventors: Richard Stephen Hans Everett
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-10-19
Filing date: 1998-10-19
Publication date: 2000-04-26
Also published as: GB9822831D0

Abstract

An alarm system generates an alarm when a disturbance in a body of water is consistent with a distress condition, such as in the case of a person 8 falling into a swimming pool 3. The system comprises a buoyant vessel 4 having a microphone 7 and a detection circuit (Fig 2, 12) for detecting disturbances in the water, a detection output signal being communicated to a base station (Fig 3, 5). At the base station, an alarm is generated by a siren and flashing light. The threshold for detection is variably set by the input of user data, and may also be set using a training phase in which the background level of disturbance is monitored. The alarm system has application to swimming pools, ponds and other bodies of water in which there is a drowning hazard, allowing remote supervision.

Description

ALARM SYSTEM This invention relates to an alarm system for generating an alarm indicative of a disturbance in a body of water being consistent with a distress condition, and in particular but not exclusively to an alarm system for use in a pool used for recreational or decorative purposes.

A significant number of accidental deaths occur, especially of young children, due to drowning in pools such as swimming pools, paddling pools or small ponds, often in relatively shallow depths of water and in circumstances such that drowning could have been avoided if the body of water had been supervised more effectively.

The present invention seeks to provide an alarm system for improving such supervision and for generating an alarm indicative of a distress condition having arisen.

According to the present invention there is disclosed an alarm system for generating an alarm indicative of a disturbance in a body of water consistent with a distress condition existing in the water, the alarm system comprising; a buoyant vessel for floating in use in the body of water and having sensing means operable to sense disturbance in the water, the system further comprising an alarm means responsive to a sensor output signal from the sensing means to generate an alarm.

Preferably the detection circuit is operable to receive the sensor output signal from the sensing means and to determine whether a distress condition exists, the detection circuit being operable to output a detection output signal input to the alarm means for initiating the generation of the alarm.

The detection circuit is preferably located in the vessel and the alarm means located in a base station deployed remotely from the body of water, a telemetry link being provided to communicate the detection output signal to the base station.

The detection circuit may operate with an adjustable threshold against which the sensor output signal is compared, either in amplitude or rate of change, and the threshold may be adjusted by the input of user data either at the vessel or at the base station.

The detection circuit may be provided with means for acquiring information about the general background level of disturbance during a training phase and may conveniently comprise a neural network for this purpose.

Preferred embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings of which; Figure 1 is a schematic representation of an alarm system for a swimming pool and having a remote base station; Figure 2 is a schematic representation of a circuit of a buoyant vessel used in the alarm system of Figure 1; Figure 3 is a schematic circuit diagram of the base station of Figure 1; and Figure 4 is a schematic circuit diagram of a circuit for implementing a learning phase in setting the threshold for detection.

In Figure 1, an alarm system 1 is provided to detect the occurrence of a distress condition in a body of water 2 in a swimming pool 3. The alarm system 1 comprises a buoyant vessel 4 which is deployed so as to float in the body of water 2 and a base station 5 deployed remotely from the pool, the base station being connected to the vessel 4 by a telemetric link 6.

The vessel 4 has a sensor 7 which is submerged in the body of water 2 and which is sensitive to disturbance in the water so as to detect the disturbance caused by a person 8 who has fallen into the water. The alarm system 1 is thereby operable to detect disturbance in the water and to communicate an alarm signal to the base station 5, the base station being equipped with alarm generating means comprising a siren 5 to provide audible warning and a high intensity flashing light 10 to provide visual warning.

Figure 2 illustrates schematically a circuit diagram for the buoyant vessel 4, a housing 11 of the vessel being indicated by broken lines. The sensor 7 in the form of a microphone is mounted on a lower surface of the housing 11 in order to detect underwater vibrations caused by the disturbance and the sensor is connected to a detector circuit 12 which analyses a sensor output signal 13 to determine whether the sensed disturbance is consistent with a distress condition.

A detection output signal 14 is output from the detector circuit 12 when a distress condition is detected and actuates output driver circuit 15 so as to actuate a transmitter 16.

The transmitter 16 sends a radio transmission corresponding to the detection output signal 14 to a receiver 17 in the base station 5 as shown in Figure 3.

The output driver circuit 15 of Figure 2 also has an output connected to a transducer 18 mounted on the buoyant vessel 4, the transducer being in the form of a piezo siren which emits a high pitched acoustic alarm tone.

The circuit of the vessel 4 is powered by a rechargeable battery 19 and a solar panel 20 mounted on the upper surface of the vessel allows the battery to be recharged.

Overall control of the circuit is effected by a controller 21 which allows the detector circuit to be armed or disarmed and to variably control the threshold at which the detector circuit 12 discriminates whether the sensor output signal 13 is representative of a distress condition. An input device 22 allows user input to the controller 21 for arming or disarming the device and adjusting the threshold.

The base station 5 similarly comprises a housing 23 as shown in Figure 3 and transducers in the form of siren 9 and flashing light 10 are prominently mounted on the housing. The receiver 17 of the base station 5 is connected to a controller 24 which responds to the detection output signal communicated via the telemetric link from the vessel 4 by actuation of output driver circuit 25 which in turn energises transducers in the form of siren 9 and light 10. The base station 5 is also provided with an input device 26 in the form of a keypad, also shown schematically in Figure 1, to enable a user to input control information to the controller 24 such as turning the alarm system on or off. Additionally, the detector circuit 12 of the vessel 4 may have an adjustable threshold which is set remotely by input to the input device 26 at the base station, data being transmitted to the vessel by a transmitter 27 at the base station and received by input device 22 in the form of a radio receiver.

In the vessel 2, the transmitter 16 and receiver 22 use a common aerial and other components of the telemetry link.

The base station 5 is also provided with a display 28 in the form of a liquid crystal display screen which outputs the current status of the alarm system 1.

In use, the alarm system 1 is deployed by placing the vessel 4 in the body of water 2 and turning on both the circuits of the vessel and base station 5. The threshold of the detector circuit 12 is then set and the alarm system 1 armed so as to respond to disturbance in the water 2 resulting in the threshold being exceeded.

When the threshold is exceeded, a detection output signal is communicated via the telemetry link 6 to the base station 5 where audible and visible alarms are generated by the siren 9 and light 10. An additional audible alarm is generated by the transducer 18 of the vessel 4. The existence of a distress condition is thereby brought to the attention of the user responsible for supervision of the pool who may then take the required action to initiate rescue. The alarm system 1 is then reset by the input of data to the input device 26 at the base station 5.

In an alternative embodiment, the vessel 4 and base station 5 referred to above are modified by providing for detection of the distress condition using an adaptive threshold arrived at by monitoring and interpreting the sensor output signal 13 during a learning phase in which the characteristics of general background noise can be measured. Detector circuits 12 of various complexity are envisaged in accordance with the present invention. A relatively simple detector circuit 12 would filter the sensor output signal 13 to allow detection of those acoustic frequencies consistent with surface agitation of the water 2 and the threshold could be established simply by monitoring the received power level over a learning period to determine a background level and then setting the threshold at a threshold level which exceeds the background level by a predetermined amount. The predetermined amount could be variably set by user input of sensitivity as described above.

A more sophisticated detector circuit 12 would include the ability to learn the characteristics of sensor output signal 13 consistent with a distress condition by a learning phase in which the background level was first monitored and then the distress situation simulated by agitating the surface of the water 2.

Figure 4 illustrates schematically circuits required for operation to include a learning phase. The sensor 7 provides sensor output signal 13 to a filter 29 which conditions the signal according to the expected frequency content of a disturbance which is to be detected. A learning circuit 30 monitors the output of the filter 29 in order to acquire knowledge of a general level of background disturbance above which a disturbance consistent with a distress condition is to be distinguished.

The output of the filter 29 is compared in a comparator 31 with a threshold input to the comparator by a threshold setting circuit 32 which sets the threshold based on data output from the learning circuit 30 and user data from input device 22.

When the output of the filter 29 exceeds the threshold, the comparator 31 outputs the detection output signal 14 which is communicated via the telemetry link 6 to the alarm generator 33 which in the previous figures comprises transducers 9 and 10.

A neural network may advantageously be utilised in the learning circuit of such a detection circuit 12.

In each of the above embodiments, the input device 22 in the vessel 4 may simply be a waterproof switch panel or potentiometer manually actuated by the user.

In the alternative, the input device 22 may be the radio receiver referred to above allowing input of information from the user input device 26 at the base station.

A further alternative embodiment is based on a simplified version of the above vessel and base station in which the microphone 7 is connected directly to an output circuit allowing the received sensor output signal 13 to be amplified and transmitted via the telemetry link 6 to the base station 5. The base station 5 may in this embodiment simply amplify the received output of the microphone 7 and delivery the output sound to a loud speaker so that the user is able to monitor the activity in the pool by listening to the speaker output.

Optionally, the detector circuit 12 may be incorporated into the base station 5 to provide any of the variants of signal detection referred to above, and consequent output of audible and/or visible alarms to the user.

Further embodiments are envisaged in which any of the above variants are modified to include a detector circuit 12 which responds to any sudden increase in the level of the sensor output signal 13. This requires the input of the sensor output signal 13 to be differentiated and the rate of change of signal compared with a threshold.

The state of the battery 19 of the vessel may be monitored and a low battery status signal generated by the controller to alert a user to a low battery situation. Such a low battery status signal is communicated to the base station via the telemetry link 6 and used to initiate a low battery alert, for example by sounding a buzzer or flashing the display 28.

Alternatives to the above embodiments are envisaged in a number of respects. For example, the sensor 7 may additionally or alternatively comprise a trembler switch to detect tilting of the vessel 4 consistent with a disturbance in the water 2. The trembler switch may include a mercury level contact switch or a pendulum device.

The alarm system 1 once triggered may be automatically turned off after a predetermined time out period set by the controller 21 of the vessel or the controller 24 of the base station.

Operation of the alarm system 1 may be periodically tested in accordance with a test routine initiated at the base station 5. The routine may include the transmission of an actuating signal to the vessel 4 to trigger the detector circuit 12. The status of the vessel 4 may be periodically monitored by handshake signals transmitted between the controller 24 and controller 21 via the telemetry link 6.

A further alternative system consists only of the vessel 4 and not the base station, the vessel being provided with an alarm siren and/or flashing light and entirely self-contained.

In each of the above described embodiments and alternatives, the controller circuits 21 and 24 may include timing devices to automatically turn on and off the alarm system 1 at appropriate times of day, as for example to turn the alarm system 1 on during periods in which a swimming pool is not directly supervised by an attendant.

The vessel 4 may be free floating or may alternatively be a tethered buoy.

The alarm system 1 in accordance with the present invention may incorporate other systems and facilities such as pool temperature monitors.

The above described circuits may be implemented in discrete circuit components or integrated circuits, or alternatively using microprocessor based technology in which the controllers 21 and 24 are processors connected to appropriate peripheral devices via appropriate interfaces.

Claims

CLAIMS 1. An alarm system for generating an alarm indicative of a disturbance in a body of water consistent with a distress condition existing in the water, the alarm system comprising; a buoyant vessel for floating in use in the body of water and having sensing means operable to sense disturbance in the water, the system further comprising an alarm means responsive to a sensor output signal from the sensing means to generate an alarm.
2. An alarm system as claimed in claim 1, further comprising a detection circuit operable to receive the sensor output signal from the sensing means and to determine whether a distress condition exists, the detection circuit being operable to output a detection output signal input to the alarm means for initiating the generation of the alarm.
3. An alarm system as claimed in claim 2, wherein the detection circuit is located in the vessel.
4. An alarm system as claimed in claim 3, comprising a base station for being deployed in use remotely from the body of water, the base station comprising the alarm means and the system further comprising telemetry means operable between the vessel and the base station and operable to communicate the detection output signal to the base station.
5. An alarm system as claimed in any of claims 2 to 4, wherein the detection circuit comprises adjustment means operable to adjust a threshold against which an attribute of the sensor output signal is compared to determine whether the distress condition exists.
6. An alarm system as claimed in claim 5 wherein the attribute is the amplitude of the sensor output signal.
7. An alarm system as claimed in claim 5 wherein the attribute is the rate of change of the sensor output signal.
8. A system as claimed in any of claims 5 to 7, wherein the adjustment means comprises an input device of the vessel facilitating the input of user data to adjust the threshold.
9. A system as claimed in any of claims 5 to 7, wherein the adjustment means comprises an input device of the base station and means for transmitting user input data from the base station to the vessel for input to the adjustment means.
10. An alarm system as claimed in any of claims 2 to 9 wherein the detection circuit comprises learning means operable to monitor the sensor output signal during a training period in which a background level of disturbance is present and to set to the threshold at a level based on the measured background level of disturbance.
11. A system as claimed in claim 10, wherein the detection circuit further comprises means for inputting user data for adjusting the sensitivity of the detection circuit.
12. A system as claimed in any of claims 10 and 11, wherein the detection circuit comprises a neural network.
13. A method of generating an alarm indicative of a disturbance in a body of water consistent with a distress condition existing in the water, the method comprising the steps of; deploying a buoyant vessel floating in the body of water; operating a sensing means of the buoyant vessel to sense disturbance in the water; and generating an alarm in response to a sensor output signal generated by the sensing means.
14. A method as claimed in claim 13, including the step of determining whether a distress condition exists by operation of a detection circuit receiving the sensor output signal from the sensing means and wherein the detection circuit outputs a detection output signal which is input to the alarm means to initiate the generation of the alarm.
15. A method as claimed in claim 14, in which the detection circuit is located in the vessel.
16. A method as claimed in claim 15, including the step of deploying a base station remotely from the body of water, communicating the detection output signal by telemetry means to the base station from the vessel, and generating the alarm at the base station.
17. A method as claimed in any of claims 14 to 16 including the step of adjusting a threshold against which an attribute of the sensor output signal is compared to determine whether the distress condition exists.
18. A method as claimed in claim 17, wherein the attribute is the amplitude of the sensor output signal.
19. A method as claimed in claim 17, wherein the attribute is the rate of change of the sensor output signal.
20. A method as claimed in any of claims 17 to 19, wherein the threshold is adjusted by operation of an input device of the vessel.
21. A method as claimed in any of claims 17 to 19, wherein the threshold is adjusted by the input of user data at the base station and by transmitting the user input data from the base station to the vessel.
22. A method as claimed in any of claims 14 to 21, wherein the detection circuit acquires information on a background level of disturbance during a training period by monitoring the sensor output signal and wherein the threshold is set based on the measured background level of disturbance.
23. A method as claimed in claim 22, including the step of inputting user data for adjusting the sensitivity of the detection circuit.
24. A method as claimed in any of claims 22 and 23, wherein the detection circuit comprises a neural network.