WO2002023501A1

WO2002023501A1 - Alarm apparatus

Info

Publication number: WO2002023501A1
Application number: PCT/SG2001/000177
Authority: WO
Inventors: Koen Verhoef
Original assignee: Koen Verhoef
Priority date: 2000-09-15
Filing date: 2001-09-04
Publication date: 2002-03-21
Also published as: AU2001288204A1

Abstract

Alarm apparatus comprising a first element having a transmitter (118) and a water sensor (108); and a second element having a receiver (214) and alarm means (204); the arrangement being such that the transmitter (118) transmits a signal to the receiver (214), the signal being inhibited when the water sensor (108) is in contact with water and the alarm means (204) being actuated when the signal is not received by the receiver (214).

Description

ALARM APPARATUS

BACKGROUND TO THE INVENTION

This invention relates to an alarm apparatus more particularly but not exclusively to be used for swimming pool drowning prevention.

A particular problem associated with swimming pools is the protection of those who do not swim, in particular children, from the risk of drowning.

Apparatus for swimming pool drowning prevention has been proposed, for example in US 6,064,309 in which an article wearable by a person includes a signal transmitter. An alert signal device is disposed near to a swimming pool so that when the article worn by the user comes within range of the device and thus near to the swimming pool, an alarm signal is actuated.

It is a disadvantage of this proposed system that it is not fail-safe and in particular is vulnerable to the transmitter malfunctioning or otherwise not working so that no alarm will be actuated. Furthermore, if the user removes the article, an alarm will not be generated even if the user then comes within range of the transmitter.

It is an object of this invention to alleviate at least one of the disadvantages of the prior art. SUMMARY OF THE INVENTION

According to the invention in the first aspect there is provided an alarm apparatus comprising a first element having a transmitter and a water sensor; and a second element having a receiver and an alarm means; the arrangement being such that the transmitter transmits a signal to the receiver, the signal being inhibited when the water sensor is in contact with water and the alarm means being actuated when the signal is not received by the receiver.

In the described embodiment of the invention, the first element is a wearable article, preferably in the form of an arm band which is worn by child or other person to be protected. The second element in the form of a portable receiver which may be carried by a parent, for example. The first element will transmit a signal to the second element and as long as that signal continues to be received, an alarm signal will not generate. However, if the water sensor of the first element comes into contact with water, this will cause the transmitted signal to cease. The absence of the transmitted signal will then be sensed by the second element and an alarm raised. Since the alarm signal is actuated when a signal from the first element is not detected, the described embodiment is fail- safe in the sense that if for any other reason, such as loss of battery power, the signal is not transmitted, an alarm will be actuated. Furthermore, the range of the transmitter of the first element may be set so that the alarm will also be actuated if the user goes out of range of the second element. Preferably, the first element further comprises a temperature sensor which is arranged to engage the skin of the user. This additional feature protects against the first element being discarded by the user for any reason since once discarded, the first element will no longer be in contact with the user's skin resulting in a temperature change, leading to inhibition of the transmitted signal and actuation of the alarm.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will now be described, by way of example, with reference with the accompanying drawings in which:

Figure 1 is a schematic view of the alarm apparatus according to the embodiment of the invention; and

Figure 2 is a schematic diagram of the apparatus shown in Fig. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to Fig. 1 , an embodiment of the alarm apparatus of the invention is shown which generally comprises a first element 100 and a second element 200. The first element is in the form of an article to be worn by a person to be protected, for example a child and is preferably an arm band 102 formed from elastomeric material, such as neoprene rubber. The arm band 102 is connected to a housing 104 in the surface of which a heat sensor 106 and a water sensor 108 are disposed. The sensors may be of any suitable form. For example, the heat sensor may be of thermistor based thermometer type and the water sensor may be of a resistance or capacitance measuring type. Means for processing the output from the sensors 106, 108 and signal generating and transmitting means are contained within the housing 104 as will be further described hereinafter.

The second element 200 is in the physical form of a pager held by a parent, for example and includes a housing 202 in the surface of which a loudspeaker 204 and a display 206 are disposed. The housing may have a clip or belt loop to enable the element to be attached to the parent's clothes.

The elements 100, 200 are arranged for wireless communication as will now be explained with reference to Fig. 2 which is a schematic block diagram of a circuitry of elements 100, 200.

Element 100 includes a CPU 110 which includes memory and internal clocking functions and which receives signal from sensors 106, 108. The CPU 110 is further connected to an EPROM 112, a signal generator 114, a modulation and optional error correction and coding module 116, a transmitter 118 and aerial 120. The element 100 is powered by an internal battery 122 and has an on/off button 124 connected to the CPU 110.

The element 200 includes a CPU 208 110 which includes memory and internal clocking functions and which sends display signals to display 206 and an audible alarm signal to speaker 204 via amplifier 210. An EPROM 222 is connected to CPU 208. The CPU is further connected to an aerial 212 via a receiver 214 and demodulator and optional error correction coding module 216. The module 200 is powered by an internal battery 218. The battery is provided with a low battery level sensor connected to CPU 208. An on/off switch 224 is further connected to CPU 208.

In use, the element 100 generates a signal which is transmitted to element 200. This signal should be essentially unambiguous so as not to interfere with signals of like devices within range of the element 200. Where no interference from other units is anticipated, the signal could simply be a carrier wave transmission at a particular frequency. In such a case, the signal generator 114 would not superimpose any signal on the modulation frequency of the transmitter 118 and could be omitted. However, in most realistic situations, some means of determining signals from different first elements 100 is needed. This can be accomplished by using different transmission frequencies but a means of sending a unique signal is preferred. To accomplish this, the first element 100 generates a unique code which is input into both EPROMS 112, 222 at the manufacturing stage. The signal could, for example, be a binary pattern of a given length, for example 256 bits, with a suitable pattern transmission period e.g. a tenth of a second. CPU 110 instructs the signal generator 114 to send that signal pattern repeatedly. The repetition of the pattern can be immediate if security considerations are paramount or can be chosen to include a delay to minimize the required battery power to send the signal without compromising security. For example, the signal may be repeated by the transmitter 118 every one or two seconds. The CPU 208 of element 200 monitors signals received by receiver 214 and demodulator 216, receiver 214 being tuned to the same frequency as transmitter 118 of element 100. If a signal is not received within a predetermined time period, which may be equal to a multiple of the pattern transmission period, CPU 208 actuates an audible alarm through speaker 204 and displays a visual alarm on display 206. In an alternative, the CPU could send out an alarm notification via aerial 212 to a telephone network, in a manner of a mobile phone, to an emergency telephone number or such like.

In order to guard against inoperability of the element 200 due to low battery power, a battery power level sensor 220 is connected to CPU 208 which will actuate an alarm via speaker 204 together with a suitable visual warning on display 206 if the battery power level falls below a chosen level. Although the operability of the alarm is not subject to correct operation of the receiver 214 and demodulator 216, since malfunction of these components and consequent non-receipt of the signal will cause the alarm to sound, preferably the CPU is connected directly to these components to perform periodic diagnostic testing.

The CPU 110 of first element 100 will continue to cause the signal to be generated unless this is halted in dependence upon signals received from sensors 106, 108. In particular, the CPU is programmed to inhibit generation of the signal if the temperature sensed by sensor 106 is outside a predetermined range including normal body temperature. Similarly, CPU 110 is arranged to inhibit generation of the signal when water sensor 108 is in contact with water. Thus, provided a sensor 106 of the element 100 remains in contact with the user's skin, so that the body temperature of the user continues to be measured and sensor 108 does not come into contact with water, the signal will continue to be generated and no alarm will be actuated in element 200. However, if the element 100 is removed by the user or the user comes into contact with water, for examply by falling into a swimming pool, the alarm will be actuated, alerting the person carrying element 200 to a possible emergency situation.

Although elements 100/200 are provided with on/off switches 124, 224, in a further preferred form of the invention, these are omitted and, instead, the elements 100, 200 are connected together by an electrical connector or lead 300 which inhibits CPU operation of both elements. Such a connector, for example, could connect to a power down facility on both CPUs. Once the lead is removed from one or other ((or both) devices, the units become active. If element 100 is not already in place on a user, an incorrect temperature sensed by a temperature sensor 106 will cause actuation of the device 200 immediately, to provide a test of operation of the apparatus. The lead 300 would also act to keep the elements 100, 200 physically together until use, to prevent one or the other being mislaid.

The embodiment described is not to be construed as limitative. For example, although the element 100 has been shown as an arm band, this could be of any suitable form to be attached to the user. When an arm band is used, this may, for example, be of a type such as used in hospitals, which cannot be removed easily. Furthermore, although the use of a heat sensor 106 is preferred, this is

not essential and can be omitted from the apparatus.

Claims

1. Alarm apparatus comprising : a first element having a transmitter and a water sensor; and a second element having a receiver and alarm means; the arrangement being such that the transmitter transmits a signal to the receiver, the signal being inhibited when the water sensor is in contact with water and the alarm means being actuated when the signal is not received by the receiver.

2. Apparatus as claimed in claim 1 wherein the first element further comprises a signal generator.

3. Apparatus as claimed in claim 1 or claim 2 wherein the signal is a binary pattern signal.

4. Apparatus as claimed in any one of the preceding claims wherein the first element is in the form of a wearable article.

5. Apparatus as claimed in claim 4 wherein the first element is in the form of an arm band.

6. Apparatus as claimed in any one of the preceding claims wherein the first element further comprises a temperature sensor, the arrangement being such that the signal is inhibited when the temperature sensed by the temperature sensor differs from body temperature.

7. Apparatus as claimed in any one of the preceding claims wherein the second element further comprises means for receiving a battery and a battery level sensor, the arrangement being such that an alarm is actuated when battery level falls below a predetermined level.

8. Apparatus as claimed in any one of the preceding claims wherein the alarm means comprises a visual and/or audible alarm.

9. Apparatus as claimed in any one of the preceding claims wherein the alarm means further comprises means for sending an alarm signal to/via a telephone network.

10. Apparatus as claimed in claim in any one of the preceding claims further comprising means for connecting the first and second elements together, the connection means being arranged to deactivate the first and second elements upon connection and activate the elements when the connection is broken.

11. A safety device wearable by a person to be protected comprising a water sensor and a transmitter, the arrangement being such that the transmitter transmits a wireless signal to a remote alarm device, the signal being inhibited when the water sensor is in contact with water so as to activate the alarm device.

12. An alarm device comprising a receiver and alarm means, the receiver being arranged to receive a signal from a separate safety device, the signal being inhibited when the safety device is in contact with water and the alarm means being actuated when the signal is not received by the receiver.