GB2422470A

GB2422470A - Proximity anti-theft alarm

Info

Publication number: GB2422470A
Application number: GB0501486A
Authority: GB
Inventors: Chi Sing Wong
Original assignee: WHAT S UP ENTPR HOLDINGS Ltd
Current assignee: WHAT S UP ENTPR HOLDINGS Ltd
Priority date: 2005-01-24
Filing date: 2005-01-24
Publication date: 2006-07-26
Also published as: GB0501486D0

Abstract

An anti-theft alarm 10 comprises two parts 12, 14 separable from each other, each part comprising a radio frequency transceiver for transmitting and receiving coded identification signals corresponding to each part. Both parts comprise an alarm which is activated in the event of the coded signal from the other part no longer being received. The device may be in the form of a key chain, with means 16 for attachment to a key ring.

Description

An Alarm Device This invention relates to an alarm device, and in

particular such a device which operates wirelessly.

According to a first aspect of the present invention, there is provided an alarm device including at least two body members which are separable from each other, wherein each body member includes a radio frequency (RF) transceiver, and wherein each of said body members is adapted to produce an alarm signal when they are away from each other beyond a pre-set distance.

According to a second aspect of the present invention, there is provided a method of issuing an alarm, including steps of (a) providing an alarm device including at least two body members which are separable from each other, (b) providing a radio frequency (RE) transceiver in each said body member, and (c) each of said body members producing an alarm signal when they are away from each other beyond a pre-set distance.

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. I is a perspective view of a wireless alarm key chain according to the present invention, with two body parts detached from each other; Fig. 2 is a block diagram of an electric circuit of a body part of the wireless alarm key chain shown in Fig. I; Fig. 3 is a detailed circuit diagram of the circuit block diagram shown in Fig. 2; Fig. 4 is a block diagram of a micro-controller used in the circuit shown in Fig. 3; Fig. 5 is a block diagram of a radio transceiver used in the circuit shown in Fig. 3, with certain external components; and Fig. 6 is a block diagram of a sound generator integrated circuit used in the body part shown in Fig. 3.

A wireless alarm key chain according to an embodiment of the present invention is shown in Fig. I and generally designated as 10. The key chain 10 includes a first body part 12 and a second body part 14. The first body part 12 includes a key ring 16 to which keys may be secured. The second body part 14 has a tongue 16 which is sized and configured to be received within a mouth 18 of the first body part 12, so as to releasably engage the body parts 12, 14 with each other. The first body part 12 has a switch 20 for activating or deactivating an electric circuit (to be further discussed below) in the first body part 12. Similarly, the second body part 14 has a switch 22 for activating or deactivating an electric circuit (to be further discussed below) in the second body part 14.

For performing the alarm function, each of the body parts 12, 14 includes an electric circuitry. The circuit arrangement in the two body parts 12, 14 may be identically constructed. The circuit arrangement shown in Figs. 2 to 6 will herebelow be discussed in the context of being an electric circuit in the first body part 12, although it should be understood that the same circuit is employed in the second body part 14.

As shown in Fig. 2, functionally speaking, the electric circuit in the first body part 12 includes an EPROM/ROM Microcontroller 30 for controlling the operation of the circuit, a Transmitter and Receiver Generator 32, a Mixer and Oscillator 34, a Sound Generator 36, a buzzer 38 for outputting sound upon receipt of signals from the Sound Generator 36, and an antenna 40 for reception of wireless signals from the second body part 14, or transmission of wireless signals to the second body part 14.

The circuit is powered by a 3V electric power supply source, e.g. two AAA dry batteries.

As shown in Fig. 3, the EPROM/ROM Microcontroller 30 includes a microcontroller 30a, the Transmitter and Receiver Generator 32 includes a radio frequency (RF) transceiver 32a, and the Sound Generator 36 includes an integrated circuit 36a.

As an example, the microcontroller 30a may be an EPROM/ROM-Based 8-Bit CMOS Microcontroller traded by SAP Link Technology Corp. of Taiwan under series No. SAP8P5X. A block diagram of this microcontroller is shown in Fig. 4. This microcontroller employs an RISO architecture with only 41 instructions. All instructions are single cycle except for program branches which take two cycles.

This microcontroller consists of Power-on Reset (POR), Brown-out Reset (BOR), Power-up Reset Timer (PWRT), Oscillator Start-up Timer (OST), Watchdog Timer, EPROM/ROM, SRAM, tn-state I/O port, I/O pull-up/opendrain controller, Power saving SLEEP mode, real time programmable clock/counter, Interrupt, Wake-up from SLEEP mode, and Code Protection for EPROM products. There are four oscillator configurations to choose from, including the power-saving LP (Low Power) oscillator and cost saving RC oscillator. This series of microcontroller can directly or indirectly address its register files and data memory. All special function registers including the program counter are mapped in the data memory.

The RF transceiver 32a may be a single chip 433 MHz radio frequency transceiver traded by Nordic Conductor ASA of Norway under series No. nRF9O5.

A block diagram of such a chip is shown in Fig. 5. This RF transceiver consists of a fully integrated frequency synthesizer, receiver chain with demodulator, a power amplifier, a crystal oscillator and a modulator. Electric current consumption is relatively low. In transmit mode, the current is only 11 mA at an output power of-lO dBm. In receive mode, the current is only 12.5 mA. Its maximum transmit output power is 10 dBm and data transmission rate (Manchester-encoder embedded) is 100 kbps.

The integrated circuit 36a may be a CMOS LSI chip traded by China Resources Semiconductor Co., Ltd., of Hong Kong under series No. A5391M01. A block diagram of such a chip is shown in Fig. 6. This chip has auto power-off function, with selectable level hold or one shot mode, a low stand-by current, 8 key input, and a wide operating voltage (from 2.5 to 5.0 volts). In particular, when the LH pin is low, the chip will operate in Level Hold mode, whereas when the LH pin is open, the chip will operate in On-shot mode.

To turn on the alarm key chain 10, the switches 20 and 22 are pressed and held for 10 seconds until an alarm sound is heard. A light-emitting diode (LED) 42 in each of the first and second body parts 12, 14 will also start flashing. To turn off the alarm key chain 10, the switches 20 and 22 are pressed and held for 10 seconds until the LEDs 42 stop flashing.

Prior to using the key chain 10 for the first time, the first body part 12 and the second body part 14 have to be paired up. To pair up the body parts 12, 14, they are placed next to each other within a distance of no more than three feet with a clear line-of-sight. The body parts 12, 14 are then turned on. The switches 20, 22 are then pressed for one second during which each of the body parts 12, 14 transmits to, and receives from, each other wirelessly a same address code. Once the correct address code is received, the body parts 12, 14 are paired up with each other, and the LEDs 42 will start flashing.

In use, the first body part 12 is detached from the second body part 14, e.g. the first body part 12 is placed in a handbag of a user, and the second body part 14 is placed in a pocket of the shirt worn by the user. When the body parts 12, 14 are within a pre-set distance, say ten feet, of each other, they can transmit wirelessly to, and receive from, each other the address code. In case the handbag is snatched from the user, e. g. by a robber, or is left behind, once the distance between the body parts 12, 14 is over ten feet, the body parts 12, 14 will fail to receive the address code from the other body part 14, 12, whereupon the integrated circuit 36a of the Sound Generator 36 will transmit signals to the buzzer 38, which causes the buzzer 38 in each of the body parts 12, 14 to give out an audio alarm.

This will have the benefit of alarming the user to the situation. If the handbag with the first body part 12 is snatched by a robber, such may scare the robber into disposing of the handbag immediately. If, on the other hand, the handbag is simply carelessly left behind, this will alert the user and assist him/her in locating the where about of the handbag.

Although the alarm device has hitherto been described in the context of a remote alarm key chain, it is envisaged that such may be an accessory used in conjunction with mobile phones, notebook computers, or other valuable belongings.

It should be understood that the above only illustrates an example whereby the present invention may be carried out, and that various modifications and/or alterations may be made thereto without departing from the spirit of the invention.

It should also be understood that various features of the invention which are, for brevity, here described in the context of a single embodiment, may be provided separately or in any appropriate sub-combinations.

Claims

CLAIMS: 1. An alarm device including at least two body members which are

separable from each other, wherein each body member includes a radio frequency (RE) transceiver, and wherein each of said body members is adapted to produce an alarm signal when they are away from each other beyond a pre-set distance.
2. An alarm device according to Claim I wherein said body members are adapted to produce a sound alarm when they are away from each other beyond said pre-set distance.
3. An alarm device according to Claim I or 2 wherein said body members are adapted to transmit an address code to each other wirelessly.
4. An alarm device according to Claim 3 wherein said body members are adapted to transmit a same address code to each other wirelessly.
5. An alarm device according to Claim 3 or 4 wherein said body members are adapted to produce said alarm signal when said body members fail to receive said address code from each other.
6. An alarm device according to any of the preceding claims wherein said alarm device is in the form of a key chain.
7. A method of issuing an alarm, including steps of (a) providing an alarm device including at least two body members which are separable from each other, (b) providing a radio frequency (RE) transceiver in each said body member, and (c) each of said body members producing an alarm signal when they are away from each other beyond a pre-set distance.
8. A method according to Claim 7 wherein said alarm signal is a sound alarm.
9. A method according to Claim 7 or 8 including a step (d) of said body members transmitting an address code to each other wirelessly.
10. A method according to Claim 9 wherein said body members transmit a same address code to each other wirelessly.
II. A method according to Claim 10 wherein said body members produce said alarm signal when said body members fail to receive said address code from each other.
12. An alarm device substantially as herein described and with reference to the drawings.
13. An alarming method substantially as herein described and with reference to the drawings.