AU4447299A - Alarm - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT

ALARM

The following statement is a full description of this invention, including the best method of performing it known to me:

ALARM

This invention relates to an alarm.

This invention relates particularly to a swimming pool alarm and it will be convenient to describe the invention with reference to this example application.

However it is to be clearly understood that the invention is capable of broader application.

Domestic or home swimming pools have resulted in numerous drownings over the years. Typically young children gain unauthorised access to a swimming pool area without the knowledge of supervising adults, then fall into the pool and drown. This 15 tragic and needless loss of life is recognised as a problem by both the community and policy makers. Legislative responses have been in the form of swimming pool fences which have been made mandatory in several states of Australia. This o requirement has definitely reduced the incidence of child drownings but it is not fool proof. For example the integrity of a child proof gate forming part of the swimming pool fences may be broken or disturbed either by the gate not being latched properly or by an elder child opening the gate to toddlers. It would therefore be advantageous if an additional means for reducing the incidence of drownings in swimming pools could be devised to be used either alone or in combination with the swimming pool fence described above.

According to an aspect of this invention there is provided an alarm suitable for use in a swimming pool area, the alarm including: A sensor for sensing the presence of a human being in the vicinity of a swimming pool; means for issuing a warning signal; and control means operatively coupled to said sensor and said warning signal means causing the warning means to issue a warning signal when the sensor senses the presence of a human being.

Thus when the alarm is armed a warning signal is issued as soon as the presence of a child is detected in a swimming pool area. This enables adults within ear shot of o• 10 the alarm to rush to the pool area and take preventative action.

:oo• Typically the sensor is a passive sensor, eg an infra-red sensor, sensing body heat and movement.

15 Typically the control means is a central processing unit, eg a micro central processing unit (CPU) of the type which can be bought off the shelf Typically the signal means comprises an audio alarm, eg a 125 decibel siren.

:i 20 Naturally the apparatus typically also includes an on/off switch for enabling the alarm to be armed. Typically the on/off switch is located in proximity to the sensor.

In a preferred form, the infra-red sensor, alarm and switch are all contained in a housing, eg a squat compact broadly rectangular housing.

Typically the alarm also includes means for energising the various components, eg siren, sensor and central processing unit. Optionally the energising means comprises at least one battery. Alternatively the energising means comprises a solar cell for receiving solar energy and converting it to electrical energy.

Typically the alarm is mounted on a fence or wall with the sensor facing towards the swimming pool. Optionally the alarm may include mounting means, eg in the form of mounting flange or mounting bracket, for mounting the alarm to the fence or wall.

Naturally the device will typically also have means for indicating low levels of power in the battery and the consequent potential for the alarm to malfunction.

10 Typically the indicating means includes a low voltage circuit between he battery and the central processing unit and an indicating means in the form of an LED.

An alarm in accordance with this invention may manifest itself in a variety of forms.

0 It will be convenient to hereinafter describe in detail one preferred embodiment with reference to the accompanying drawings for the purposes of instructing persons having an interest in this subject matter how to carry out the invention. It is to be clearly understood however that the specific nature of this description does not *ooo supersede the generality of the preceding statements. In the drawings: 20 FIG.1 is a schematic circuit diagram of an alarm in accordance with one ooo• embodiment of the invention; FIG.2 is a front elevation of the alarm of FIG.1; FIG.3 is a plan view of one possible arrangement and orientation of the alarm of FIG. 1 in use at a swimming pool; and FIG.4 is a plan view of anther possible arrangement.

In FIG. 1 reference numeral 1 refers generally to an alarm.

The alarm 1 comprises broadly a passive infra-red sensor 2 operatively connected to a central processing unit 3 which is a micro central processing unit (CPU). The CPU 3 is in turn operatively connected to an audio alarm 4 which is a siren.

The CPU 3 is also operatively connected to means for energising the components in the form of a battery 5. In one embodiment the battery 5 comprises 8 x AA penlight batteries. An on/off switch 6 is connected in series to the CPU 3 and battery 5 intermediate the two components 4. This enables the battery 5 to energise the CPU 3 when the alarm 1 is armed and to cut off power to the CPU 3 when the 10 alarm 1 is switched off The passive infra-red sensor 2 is of the type which can be bought off the shelf and would be well known to persons skilled in the art. Accordingly it will not be described in further detail in the specification. Typically the sensor 2 will have a 15 range of 8 meters throught 1500.

""*"Similarly the micro CPU 3 is of a type which can be bought off the shelf and would be well known to persons skilled in the art. Accordingly it will not be described in further detail in the specification. Naturally the CPU 3 will be calibrated such that S: 20 it is not too sensitive that is set off by a flying insect or the like. This is achieved by electronically modifying the CPU.

The alarm 1 may also include an optional charging circuit 8 for recharging the battery from a domestic mains supply. The alarm 1 also includes a low voltage detector circuit 9. Typically the alarm consumes 15MA on standby and 140MA with siren activated.

FIG.2 shows an external view of the alarm 1. The various components are contained within a compact squat housing 15 which is mounted on a support surface, eg a wall of fence. The housing 15 has an attachment bracket (not shown) for effecting the attachment to the wall or fence. The vent of the siren 4 is located on the underside of the housing 15. In one embodiment the siren is a 110 decibel siren.

A front face 16 of the housing 15 has the on/off switch 6 and a light 17, eg a status LED to indicate whether the alarm 1 is armed or off.

oo In use, the alarm 1 is armed by switching the switch 6 to the on position. If a human body having a mass greater than 3kg then moves into the field of the infra red sensor 2, this is sensed by the passive infra red sensor 2 which transmits a signal to the siren to sound.

The light 17 lets you know that the alarm is switched on. When the alarm is switched on it takes 1 minute to arm. This gives you 1 minute to clear the area without triggering the alarm. It also gives the alarm 1 time to sense its surroundings before going into standby mode.

If the battery voltage drops below threshold level, this is detected by the low voltage detector circuit 9 causing the LED 17 to flash and optionally also the alarm 1 to emit a sound. This then alerts users to this condition.

FIGS.3 and 4 indicate different layouts of the alarm in use. In FIG.3 the housing is mounted on the wall 20 of the housing 15. In FIG.4, the alarm 1 is shown mounted on a swimming pool fence. In both cases the UV sensor 2 is directed outwardly such that its field covers the full area of the pool 6 It will of course be realised that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as is herein set forth.