GB2136619A

GB2136619A - Personal alarm apparatus

Info

Publication number: GB2136619A
Application number: GB08402977A
Authority: GB
Inventors: Henry Vaughn Griffith; William Clark Marrs
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-02-08
Filing date: 1984-02-03
Publication date: 1984-09-19
Also published as: GB8402977D0; GB2136619B

Abstract

Apparatus for use with and connection to a portable personal radio transmitter or transceiver which enables the latter to broadcast an alarm signal if the wearer is in distress, without prejudicing the voice functions of the transmitter/transceiver. It may be an add-on module to an existing transceiver comprising a tilt switch 6, time delay 12,1 KHz oscillator 14 and relay 16. The output alarm signal (18) is connected to the external microphone socket of the transceiver. The relay contacts (closed when the relay is activated) connect to the terminals which are normally shorted by the press-to-transmit button of the external microphone. <IMAGE>

Description

SPECIFICATION Personal alarm apparatus This invention relates to apparatus for use with a personal radio transmitter which is actuated into transmission of an alarm signal when the person carrying the apparatus is in distress.

Personal alarm transmitters wherein a radio transmission signal is actuated by an attitude-sensitive switch are known. The attitude-sensitive switch is typically a mercury tilt-switch which, in the substantially non-upright position, actuates a timing circuit.

If the tilt switch does not return to the substantially upright position within a given time, the timimg circuit times out to actuate a radio-transmitted alarm signal for receipt by a remote receiver. The apparatus is worn on the person and can give warning should the wearer collapse (i.e. become non-upright) for more than the given time. The latter is, of course, set appropriately to enable the wearer to stoop normally without actuating the alarm.

These known transmitters and receivers are dedicated devices. They make no accommodation for any other function. At present, it is customary for workers in many employments to carry either personal radio transmitters or transceivers. Examples are public service employees such as firemen and policemen, or workers in hostile environments such as on ships, oil rigs, or in chemical or mechanical plant. We have now devised an apparatus which can be employed to complement such transmitters or transceivers and thus equip the latter with a personal alarm facility, whilst not reducing the transmitter/ transceiver normal voice function.

According to the invention we provide an apparatus for use with and connection to a portable personal radio transmitter, which comprises: an activity - or attitude-sensitive sensor, time delay means actuated by said sensor to provide an output signal after a predetermined time period, means responsive to the output signal of the time delay means to provide an output alarm signal, means connectable with the signal input circuit of the transmitter to provide the output alarm signal thereto, and means responsive to the output signal of the time delay means to actuate transmission of the transmitter.

The apparatus may be installed within the housing holding the transmitter or transceiver and derive power from the batteries of the latter. Alternatively, it amy be designed as an add-on module to an existing transmitter or transceiver, when it is preferably contained in a separate housing worn on the person and electrically connected to the transmitter or transceiver. In the latter case, it may have its own power supply and it is typically clipped onto the belt of the wearer or held firmly upright in a pocket. Only when the wearer is in distress, e.g. adopts a substantially non-upright position for more than a predetermined time period, is the transmitter/transceiver actuated into providing an alarm signal.

If the apparatus is worn separately, then the output signal to the transmitter/transceiver may be supplied, for example, electrically to an external microphone socket, or via the internally-installed microphone of the transmitter/transceiver (either as an audible signal to the microphone or as an electrical signal connected to the microphone output leads). If the apparatus is installed in the same housing as the transmitter/transceiver, then the output signal is arranged for internal connection to the transmitter/transceiver signal input circuit.

The output alarm signal of the apparatus may be continuous whilst on (e.g. a continuous tone) or it may be in a unique form (e.g. a unique tone or series of tones) coded to identify the transmitting unit issuing the signal. The signal may also be issued on an intermittent basis e.g. "on" for 10 seconds, "off" for 10 seconds, "on" for ten seconds etc. to enable the receiving unit to try to contact the transmitting unit during the "off" periods. This would be of use should the apparatus transmit an alarm unnecessarily.

The activity- or attitude-sensitive sensor may be a tilt switch activated when the wearer assumes a position of, say, more than 30 to the vertical. It may be a movement-sensitive sensor which activates the timing device if there is no movement by the wearer.

It may be a normally-closed switch which permanently actuates the timing circuit unless manually overridden (opened) within the given time period by the wearer.

A preferred embodiment of the invention will now be described, by way of example oniy, with reference to the accompanying drawing, in which: Figure I is a block circuit diagram of the preferred apparatus for use with a separate portable personal radio transceiver, and Figure 2 is a more detailed diagram of the Figure 1 circuit.

Referring to Figure 1, the apparatus is housed in a separate module for attachment to the belt of the wearer. It is connected to the wearer's transceiver through the external microphone socket. This normally takes a high impedance voice signal from the external microphone and includes a pair of terminals which are shorted from the external microphone to place the transceiver into the transmit mode - i.e. via the "press to transmit" button on the external microphone.

The apparatus comprises a battery 2, battery switch 4, attitude-sensitive memory tilt switch 6, and a manually-operable switch 8. An I.e.d. 10 is shunted across battery 2 and switch 4. Switches 6 and 8 initiate a timing circuit 12 which is connected to a 1KHz oscillator 14 and to a relay 16. The contacts of the latter are normally-open. A high impedance output 18 from oscillator 14 is supplied to an appropriate connector (at 20) for connection with the external microphone socket of the transceiver. The contacts of relay 16 are supplied to connector 20 for connection with the terminals which are shorted to actuate the transmission mode of the transceiver.

The apparatus functions as follows, with switch 4 closed. Manual switch 8 is normally open, and tilt switch 6 also remains open whilst the wearer is upright. No signal is supplied to the transceiver. In the event that the wearer collapses or stoops normally, switch 6 closes and initiates timing circuit 12. If the wearer resumes an upright position within a preset time (e.g. 20 seconds) the timing circuit is reset without an output signal being generated. If however the wearer remains non-upright for more than the preset time than the timing circuit 12 times out to actuate both oscillator 14 and relay 16. The latter causes the relay contacts to close, thus shorting the "transmit mode" terminals of the transceiver.The 1 KHz oscillator tone is thus injected into the microphone circuit of the transceiver and is transmitted over the voice channel to a remote receiver held by a third party.

The manual switch 8 in parallel with the tilt switch 6 acts as a test switch for the apparatus. When on, the I.e.d. 10 illuminates to show that the battery is effective. A test output alarm signal is also produced.

In the event that it is desired to code the alarm transmission depending uniquely upon the transmitter, then this may be achieved by including a tone encoder 22 shown in phantom in Figure 1.

With the circuit as described, the wearer may still use the internally-installed microphone and transmit switch of the transceiver for voice transmissions.

However, if desired, the apparatus of the invention may also include a connector to take the external microphone to bypass the oscillator 14 and relay 16 for voice communication.

The detailed circuitry of the apparatus is shown in Figure 2. The timing circuit 12 and 1 KHz oscillator 14 are provided in a combined commercial integrated circuit Type 556 (Radiospares, London). The latter (shown in the drawing as 1 Cl a and 1 Cl b) is a low power timer which may be arranged to provide an output signal in an astable mode at 1 KHz with appropiate timing components. In Figure 2, identical reference numerals to those of Figure 1 are employed.

Claims

1. An apparatus for use with and connection to a portable personal radio transmitter, which comprises: an activity- or attitude-sensitive sensor, time delay means actuated by said sensor to provide an output signal after a predetermined time period, means responsive to the output signal of the time delay means to actuate transmission of the transmitter.

2. An apparatus according to claim 1 when contained in a housing separate from the transmitter and comprising connector means for providing said output alarm signal to the transmitter.

3. An apparatus according to claim 2 wherein the connector means connects with an external microphone socket of the transmitter.

4. An apparatus according to any of claims 1 to 3 wherein the means to actuate transmission of the transmitter comprises a relay whose contacts are shorted upon actuation.

5. An apparatus according to any of claims 1 to 4 which additionally includes means to encode the output alarm signal uniquely as a characteristic of the transmittee.

6. An apparatus according to any of claims 1 to 5 which includes means to cause the output alarm sigrral to be generated on an intermittent basis.

7. An apparatus according to any of claims 1 to 6 wherein the activity- or attitude-sensitive sensor is a tilt switch.

8. An apparatus for use and connection to a portable personal radio transmitter substantially as herein described with reference to the accompanying drawings.