GB2399440A

GB2399440A - Proximity alarm

Info

Publication number: GB2399440A
Application number: GB0305452A
Authority: GB
Inventors: Paul Sleeman
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-03-10
Filing date: 2003-03-10
Publication date: 2004-09-15
Also published as: GB0305452D0

Abstract

A proximity alarm comprising a base unit 1, one or more remote units 3,4,5,6 and means to monitor the distance between the base unit and the one or more remote units. Alarm means, such as LEDs 9,10,11,12, are actuated when the distance between the base unit and a remote unit exceeds a predetermined distance for a predetermined period of time. The means for determining the distance between the units comprises transmitters mounted in the remote units which transmit short range coded signals to a receiver mounted in the base unit. The base unit actuates an alarm if a signal is no longer received, ie. a remote unit is out of range. The base unit may be worn on the human body and may be provided with ports in which the one or more remote units can be carried when not in use. The remote units can be carried by a wrist strap 20 provided with a housing for carriage of the unit, which can be worn by a child.

Description

Proximity Alarm This invention relates to a proximity alarm, particularly,

but not exclusively to be used to indicate when a child has wandered too far from a parent or guardian.

In a public environment it can be easy to lose sight of a child. For example ir shops where children can be hidden from view behind display shelves, or in an amusement park where excited youngsters' curiosity can lead them to run off.

The above problem is exacerbated if more than one child is being supervised, and can be very difficult if there is a group of children.

The present invention is intended to provide a novel approach to solving some of the above problems.

According to the present invention, a proximity alarm device comprises a base unit, one or more remote units, means to monitor the distance between the base unit and the one or more remote units, and alarm means, in which the alarm means activates when the distance between the base unit and a remote unit exceeds a pre- determined distance.

In a preferred construction the alarm means can activate when the distance between the base unit and a remote unit exceeds a pre-determined distance for a pre-determined time period.

The monitoring means can be a transmitter and a receiver. The transmitter can be carried by either the base unit or the one or more remote units, but in a preferred construction the transmitter may be carried by the one or more remote units, and the receiver can be carried by the base unit.

The alarm means can be a sound or a light emitter or a vibrator, and it can be carried by either the base unit or the one or more remote units. In a preferred construction the alarm means may be carried by the base unit.

It will be appreciated that any number of remote units can be provided, but in a preferred construction four remote units may be provided. In one construction the remote units can be carried in ports provided in the base unit when not in use.

Further, one or more of the remote units can be removed from the base for use. With this arrangement the alarm means can be provided with a number of separate alarms to indicate which of the remote units has exceeded the distance from the base unit. These alarms can take the form of lights mounted adjacent the remote unit ports, which activate when the unit in question has triggered the system.

The predetermined distance between the units, beyond which the alarm can activate may be 20 feet (6.2 metros), and the predetermined time period before the alarm activates may be four and a half seconds.

In a preferred construction each of the one or more remote units may be provided with an encoder chip which produces four frames of coded signal once every second. The signals are transmitted via a 433MHz hybrid transmitter board and an aerial. The transmitter board can be controlled by a potentiometer to restrict its range.

The base unit may be provided with a super regenerative receiver board, which is matched to the one or more transmitters. The four frames of signal which are received are passed to a decoder chip, the code of which matches the transmitter code. The base unit may also have a four and a half second timer which is reset each time three correct codes in the group of four is received. If the time runs down without the correct codes being received, the alarm will be activated.

Both the base unit and the one or more remote units are provided with an appropriate battery.

The base unit and the one or more remote units can be provided with means to wear them on the human body. In one construction the remote units can be worn around the wrist, and the base unit can be worn around the torso.

In a preferred construction the device is adapted to be used by a parent or guardian and a number of children, although it will be appreciated that the device can be used in other circumstances, for example with a group of adults, or with an animal cater and one or more animals.

The invention can be performed in various ways, but one embodiment will now be described by way of example, and with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic front view of a proximity alarm according to the present invention; and, Figure 2 is a diagrammatic view of the internal components of the proximity alarm as shown in Figure 1.

In Figure 1 a proximity alarm device 1 comprises a base unit 2 and four remote units 3, 4, 5, 6, which are individually numbered.

In Figure 2, the alarm device 1 also comprises means to monitor the distance between the base unit and the four remote units in the form of proximity measuring apparatus, generally designated 7, and alarm means in the form of vibrator 8, and LEDs 9, 10, 11, 12. The vibrator 8 and the LEDs 9, 10, 11, 12 activate as described below when the distance between the base unit 2 and a remote unit 3 or 4 exceeds a pre-determined amount.

As shown in Figure 1 the base unit 2 can carry the remote units 3,4,5,6 in four corresponding ports (shown in Figure 2 only) 13, 14, 15, 16. The base unit 2 is provided with a laterally extending flange 17, which is constructed from a transparent material, and which protects the units 3,4, 5,6 when they are disposed in the ports.

The ports are located adjacent the LEDS 9, 10, 11, 12.

The base unit 2 is provided with an on/off switch 18, (which also acts as a reset switch) and a shoulder strap 19, which is dimensioned to be worn by an adult.

The remote units 3,4,5,6, can be carried by a wrist strap 20, which is provided with a housing 21 for carriage of the unit, and which is dimensioned to be worn by a child. The wrist strap is secured on the user by the opposing surfaces of a hook and loop fastener 22. i As shown in Figure 2, the base unit 2 further comprises a receiver board 23, an encoder chip 24, a timer 25, a switch 26 and a battery 27. In addition the remote units 3,4,5, 6 each further comprise a transmitter board 28, an encoder chip 29, a potentiometer 30, an aerial 31 and a battery 32.

In use, the parent or guardian dons the base unit by means of shoulder strap I 19, and the children in their care each don a wrist strap 20. The parent or guardian removes a remote unit, (in Figure 1 unit 6 has been removed), and places it in the housing 21. The parent or guardian can remove any number of units for use. The remote units 3,4,5, 6, are activated when they are removed from the ports 13, 14, 15, 16, and the base unit 2 is activated by the operation of switch 18.

Referring to Figure 2, two remote units 3,4 have been removed from the ports 13,14 for use. Once activated the encoder chips 29 in the remote units 3, 4 produces four frames of coded signal once every second. The signals are transmitted from the units 3,4 via the transmitter boards 28 and the aerials 31. The transmitter boards 28 are 433MHz hybrid transmitter boards, the range of which are restricted to 20 feet (6.2 metros) by the potentiometers 30.

The four frames of signal from each remote unit 3, 4, are received by the receiver board 23 in the base unit 2. The receiver board 23 is a super regenerative receiver board which is matched to the four transmitters, and which can receive signals from all four. The signals which are received are passed to a decoder chip 24, the code of which match the codes transmitted by the remote units 3, 4.

When a remote unit is removed from a port and the base unit 2 is switched on, the timer 25 will run a four and a half second count for each removed unit.

If three of the four codes from one unit are received correctly a signal is sent i from the chip 24 to the timer 25. This signal resets the timer delay for that unit. If the timer 25 is not reset in time, switch 26 is operated which activates the vibrator 8, and activates the LED which corresponds to the port of the unit in question.

As shown in Figure 2, unit 3 is removed from the base unit 2, and is disposed distance A away from it. Distance A is less than 20 feet (6. 2metres), therefore, the signals sent from the unit 3 should be received by the base unit 2, and the timer 25 1 will be reset every second, and the vibrator 8 and LED 9 will not be activated.

However, unit 4 is disposed distance B away from the unit, which is more than feet (6.2 metros). Therefore, the base unit 2 will not receive signals from unit 4, and in four and a half seconds time the timer 25 will activate the switch 26, and the vibrator 8 and LED 10 will operate. This indicates to the user of the base unit 2, that the holder of unit 4 is more than 20 feet (6.2 metros) away, and appropriate action can be taken.

lf the unit 4 returns to a distance of less than 20 feet (6.2 metres) from the base unit within the four and a half second delay, and three of the four transmitted signals are correctly received, the timer will be reset, and no alarm will be activated.

Once activated the vibrator 8 and the LED 10 will continue to operate until the on/off switch 18 is operated and the device is re-set. In an alternative embodiment (not shown) the vibrator 8 and the LED 10 will cease to activate once signals are again received from the missing unit.

It will be appreciated that the above described embodiment can be altered without departing from the spirit of the invention. For example, any number of remote units can be provided, and any kind of alarm means, for example an audible alarm, can be included. Further, the distance beyond which the alarm activates can i be varied via an appropriate dial or switch.

In addition, in an alternative embodiment, (not shown) the device can be provided with a reverse arrangement of transmitters and receivers, so that the remote units can carry an alarm which activates when the user of the remote unit ventures more than 20 feet (6.2 metros) from the base unit. This arrangement can be provided instead of the arrangement as shown in Figures 1 and 2, or alongside it. I With this arrangement both a parent or guardian and a child will know if they have become separated and appropriate action is necessary.

In one further alternative embodiment the remote units can be adapted to be carried by animals, for example dogs, so a dog walker can know when animals in their care are more than a certain distance away.

Thus a proximity alarm device is provided which can discreetly indicate to a parent or guardian when a child in their care has wandered off. Further, this device can be used in any circumstance where it is important that individuals stay close together, whether or not they are a human adult a child.

Claims

Claims 1. A proximity alarm device comprising a base unit, one or more

remote units, means to monitor the distance between the base unit and the one or more remote units, and alarm means, in which the alarm means activates when the distance between the base unit and a remote unit exceeds a pre- determined distance.
2. A proximity alarm device as claimed in Claim 1 in which the alarm means activates when the distance between the base unit and a remote unit exceeds a pre- determined distance for a pre-determined time period.
3. A proximity alarm device as claimed in Claim 2 in which the monitoring means comprises a transmitter and a receiver.
4. A proximity alarm device as claimed in Claim 3 in which the transmitter is carried by the one or more remote units and the receiver is carried by the base unit.
5. A proximity alarm device as claimed in any of the preceding Claims in which the alarm means is a vibrator and/or an LED.
6. A proximity alarm device as claimed in Claim 5 in which the alarm means is carried by the base unit.
7. A proximity alarm device as claimed in Claim 6 in which the one or more remote units can be carried by the base unit when not in use.
8. A proximity alarm device as claimed in Claim 7 in which the one or more remote units can be carried in one or more ports provided in the side of the base unit, and in which the base unit is provided with a laterally extending flange which extends beyond the end of the one or more remote units carried by the base unit.
9, A proximity alarm device as claimed in Claim 8 in which in which the alarm means is a vibrator and one or more LEDs, which are each disposed adjacent one of the one or more ports, and in which an LED is activated when the remote unit corresponding to the port adjacent the LED exceeds the pre-determined distance from the base unit.
10. A proximity alarm device as claimed in any of the preceding Claims in which the pre-determined distance is substantially 20 feet (6.2 metros).
11. A proximity alarm device as claimed in any of Claims 2-10 in which the pre- determined time period is substantially four and a half seconds.
12. A proximity alarm device as claimed in any of Claims 4 to 11 in which the one or more remote units are provided with an encoder chip which produces four frames of coded signal once every second, a 433MHz hybrid transmitter board, a potentiometer and an aerial, in which the transmitter board is adapted to transmit the coded signal via the aerial, and the potentiometer is adapted to restrict the range of the transmitter.
13. A proximity alarm device as claimed in Claim 12 in which the base unit is provided with a super regenerative receiver board, which is matched to the one or more transmitters, a decoder chip, the codes of which match the transmitter codes and a timer adapted to activate the alarm means at the end of a four and a half second delay, in which the timer is reset each time the receiver board receives three of the four codes transmitted by the one or more remote units
14. A proximity alarm device as claimed in any of the preceding Claims in which the base unit and the one or more remote units are provided with means to wear them on the human body.
15. A proximity alarm device as claimed in Claim 16 in which the one or more remote units can be worn around the wrist, and the base unit can be worn over the shoulder.
16. A proximity alarm device as claimed in Claim 15 in which the base unit is adapted to be worn by an adult, and the remote units are adapted to be worn by children.
17. A proximity alarm device as claimed in any of Claims 1-13 in which the base unit is provided with means to wear it on the human body, and the one or more remote units are provided with means to wear them on an animal body.
18. A proximity alarm device as claimed in any of the preceding Claims in which four remote units are provided.
19. A proximity alarm device substantially as described herein and as shown in the accompanying drawings.