GB2222709A - Alarm system - Google Patents

Abstract

An alarm device adapted to be connected to the domestic electricity mains supply (14), comprises a transmitter device (A) and a receiver device (B); the transmitter device having encoding means (13) for generating encoded signals, switching means (15, 24, 35) for controlling the transmitter device to cause coded signals indicative of the location of the device to be transmitted via the main supply for reception by the receiver device (B) of one or more further similar alarm devices; and the receiver device (B) having means for decoding such location signals upon receipt via the mains supply (14); the transmitter device and the receiver device further comprising means (18, 30) for effecting speech communication between two or more such alarm devices via the mains supply (14). <IMAGE>

Description

TITLE: ALARM SYSTEM This invention relates to an alarm device more particularly but not solely for domestic use in a local area.

There are a number of different alarm systems available for people who become ill, are attacked in their homes or are burgled, e.g.

1) Burglar alarm systems connected to a telephore system which are connected to a police station. These have the disadvantage that they are frequently triggered accidentally and waste police time. Also, telephone lines can be cut by possible intruders.

2) Burglar alarm systems which activate an alarm device on the outside of the premises. These are often triggered inadvertently and other people outside the home, for this and other reasons, tend to ignore them.

3) Alarm systems, mainly for elderly people which are activated by a radio device attached to a person which, when operated, will trigger a unit attached to a telephone system which is connected to a permanently available operator or others, who endeavour to establish speech contact with the calling person and then with the police, hospital or ambulance services and/or with the nearest neighbours of the person owning the system. This system is expensive and requires constant paid supervision, and since it is dependant on telephones, the line can be cut by possible intruders.

Objects of the present invention are that it is relatively cheap, does not use vulnerable telephone lines, requires very little installation effort, does not rely on paid supervision, and does not require alarms outside the premises. Also the invention enables a few neighbours with similar units to be in contact with each other, so that there is a local selfhelp group within a limited area.

According to the invention there is provided an alarm device comprising a receiver for application to an electricity mains supply circuit having means for decoding signals transmitted via said mains supply circuit from at least one source located at a position remote from said device, a transmitter having means for generating encoded signals, switching means for controlling said transmitter to cause coded signals indicative of the location of said device to enter said supply circuit for reception by a receiver of another device located at said other position, and further transmitter and receiver means for effecting speech communication through said supply circuit.

The invention will now be described by way of example with reference to the accompanying drawing which is a circuit diagram of an alarm system suitable for use by a number of households in a neighbourhood watch group.

The alarm device which is to be used in conjunction with one or more identical devices connected to and powered from an electricity mains supply circuit uses the mains supply line to send control signals and speech signals of the type used in telephone systems.

It is intended that the identical devices should be connected to the same secondary winding of the local distribution transformers. Additionally, connecting means may be used to bridge between/across other secondary windings for transmission to units connected to those windings referred to hereafter as the "network".

The device constructed as a single unit consists of a transmitter section A and a receiver section B. The transmission section A consists of a keyboard 9 or other type of entry suitable for supplying signals via an on/set switch 10 to enable a series of digits to be fed into, and retained in, a callback number store 11 representative of the particular location at which the unit is installed, such as a telephone number or other identification number of a type which has been agreed by the owners of similar units attached to the same network. The callback number store 11 may be contained in a microprocessor 12.

A signalling means 13 serves to transmit the stored callback number to the electricity mains circuit 14 via contacts 15 and contacts 16 and an amplifying, protection circuit and isolation means 17, and a microphone 18 suitable for coupling speech signals to said signalling means for transmission to the receiver.

Such signalling means is suitable for use in the relatively noisy environment of the mains supply.

The receiver B comprises a signal decoder 22 connected to the circuit 14 via contacts 23 and contacts 24 serving to decode the signal representing the number from any other identical device connected to the same system. The output of said decoder 22 is connected to the input of a digital incoming number store 25 which may be contained in said microprocessor 12.

A number display 26 connected to the store 25 via contacts 27 for displaying an incoming number and to said store 11 via contacts 28 for displaying the callback number during setting by the owner of the unit. The display 26 is capable of displaying any digits 0-9 at each of the digit displays, and other information symbols.

Furthermore, the display 26 is preferably capable of indicating that the unit is in an "ON" condition when it is capable of sending and receiving numbers, a "SET" position when the callback number applicable to the unit is being fed into the callback number store, and indication that the unit is sending a number or receiving a number.

More than one number may be stored. Successive pressing of a "receive" push-button operating contacts 19 will display them in sequence.

A speaker 30 is connected to the store 25 via an amplifying and protective circuit 31 and contacts 32 for audible indication from the store 25 that an incoming number has been received, and to receive speech from the unit from which the incoming number originated.

A warning lamp 33 is connected to said store 25 via contacts 34 for visible indication from the store 25 that an incoming number has been received.

A remotely controlled relay 35 is provided for the control of the microprocessor 12. The relay 35 is operable by an energising unit or units of a known kind e.g. those used for controlling the locks of vehicles which, when operated, will send a signal to the transmission section A of the alarm device. Such units may be in the form of pendants which can be worn on the wrist or round the neck of the user of the device.

Alternatively, the relay 35 may be actuated by means of pressure mats or other similar devices already known and which, by themselves do not apply solely to this or any other such system, or other intruder detection systems which can provide the required signal.

The components of the unit are preferably energised from the electricity mains supply; possibly with secondary support by batteries for use during failure of the mains supply.

Parts, or all, of the unit may be incorporated in a suitably modified telephone type handset.

Operation of the units is as follows: Units as described above are installed by plugging them into the mains electricity supply at the residences of two or more people connected to the same network.

The owners of these units agree among themselves on a system of identification (telephone numbers, house numbers or any such system). Each owner then feeds his/her identification number into the calling store 11 of his unit, either by setting on "ON/SET" switch 10 to the "SET" position and then using the keyboard 9 or other push-button controlled system. The "ON/SET" switch 10 is then switched to the "ON" position.

The owner of each unit either places suitable mats or other devices such as pendants, each with a suitable transmitter in position.

When the mats are activated or the pendant pushbuttons pressed, the number store 11 and encoder 13 are connected by the contacts 15 (by way of a relay not shown) to the mains electricity line 14 and the callback number transmitted to other similar units attached to the same network.

The transmitted number is received and stored in the incoming number store 25 of one or other similar units previously described, and the first (or the latest whichever is chosen) number received is shown in the number display 26. A warning sound is sent from the microprocessor 12 of that other unit to the speaker output 30 and to the warning lamp 33 (which may be incorporated in the number display).

When the owner of the other unit hears the warning sound and/or sees the warning light then, by pressing a "receive" button which operates contacts 19, 16, 23, 32, 37 and 34, the warning lamp 33 is disconnected, the speaker output 30 is disconnected from the microprocessor 12 and connected to the electricity mains supply 14 via contacts 37. The microphone 18 of that unit is simultaneously connected by contacts 19 to the electricity mains supply 14 and the encoder 13 disconnected by the opening of contacts 16.

The owner of that other unit may then speak to the owner of the unit which initiated the above procedure, after the latter owner has also pressed the "receive" push-button of his/her unit, or the microphone has been connected after delay in time after the initiating remote energising device has activated the unit. In addition, simultaneously, the encoder 13 is disconnected and the speaker output 30 connected to the electricity mains supply 14. The calling number store output is de-activated by the microprocessor.

Furthermore it will be necessary to include modulation means suitable to convert said speech signals to a form suitable for transmission via the network.

The owners of the units may converse or, if no oral reply is received from the intitiating unit, the answering party may either release his "receive" pushbutton and visit the person owning the initiating (calling) unit or summon help.

After one call has been dealt with, the answering owner my press the "receive" button again and, if a second number is stored, it will be displayed and the owner of that unit may be contacted. If no other numbers are stored, no numbers will be shown on the display.

The number display may also indicate the conditions "ON", "SET", "SENDING", and "RECEIVING".

It is important to recognise the need for integrity of operation in that the system described is outlined in principle only. It will be necessary to utilize well known transmission/modulation techniques possibly combined with error detecting/correcting systems to ensure that the alarm signals and numbers are transmitted and received reliably and that the subjective quality of the speech system is acceptable to the users.

Furthermore such protection is necessary to prevent inadvertent operation by electrical noise imposed on the network by other apparatus either of a general nature e.g. electric motors, microwave cookers/televisions and also other devices which transmit information by the network.

Claims (16)

CLAIMS:

1. An alarm device adapted to be connected to the domestic electricity mains supply, comprising a transmitter device and a receiver device; the transmitter device having encoding means for generating encoded signals, switching means for controlling the transmitter device to cause coded signals indicative of the location of the device to be transmitted via the mains supply for reception by the receiving means of one or more further similar alarm devices; and the receiver device having means for decoding such location signals upon receipt via the mains supply; the transmitter device and the receiver device further comprising means for effecting speech communication between two or more such alarm devices via the mains supply.

2. An alarm device as claimed in Claim 1, wherein the transmitter device includes means to store a code number indicative of the location of the device which is encoded by said encoding means.

3. An alarm device as claimed in Claim 2, including means to display a code number arranged to selectively display the code number indicative of the location of the device.

4. An alarm device as claimed in Claim 2 or 3, including means for generating said code number indicative of the location of the device selectively connectable to said storage means.

5. An alarm device as claimed in Claim 1, 2, 3 or 4, including means to cause said coded signal indicative of the location of the device to be transmitted down said mains supply upon the operation of a remote sensing device.

6. An alarm device as claimed in any preceding Claim, wherein said means for transmitting speech communication comprises a microphone selectively connectable to said mains supply through an interface.

7. An alarm device as claimed in any preceding Claim, as dependent on Claim 3, wherein the receiver device comprises means for storing an incoming coded number indicative of the location of a similar device which is selectively connectable to said display device.

8. An alarm device as claimed in any preceding Claim, wherein said means for receiving speech communication comprises a loudspeaker selectively connectable to said mains supply through an interface circuit.

9. An alarm device as claimed in Claim 8, wherein said speaker is arranged to give an audible warning of the receipt of a coded number indicative of the location of another similar device.

10. An alarm device as claimed in any preceding Claim, wherein said receiver means includes a warning lamp operable to give a visible warning of the receipt of a coded number indicative of the location of another similar device.

11. An alarm device as claimed in any preceding Claim, including a press to receive switch arrangement arranged to disconnect said encoding means from the mains supply and connect the speaker to the mains supply.

12. An alarm device as claimed in Claim 11, as dependent on Claim 6, wherein said press to receive switch arrangement connects said microphone to the mains supply through said interface.

13. An-alarm device as claimed in Claim 11 or 12, wherein said press to receive switch arrangement disconnects said decoding means from the mains supply.

14. An alarm device as claimed in Claim 13, as dependent on Claim 8, wherein said press to receive switch arrangement connects said speaker to the mains supply through said interface.

15. An alarm device as claimed in any preceding claim, wherein the transmitter device and/or the receiver device include(s) neans for ensuring the integrity of the coded signals transmitted and decoded.

16. An alarm device substantially as herein described with reference to the accompanying drawing.