PERSONAL ALARM TRANSMITTER FIELD OF THE INVENTION
This invention relates to personal alarm devices which function to sound and transmit an alarm in emergency situations.
BACKGROUND ART
Alarm devices are known in which actuation of an alarm button will activate the transmission of a signal to a central receiver, so that assistance may be sent to the location of the actuated device. The known devices have not provided sufficient flexibility in their operation, and have not satisfactorily responded to conditions in which the user may be unable to actuate the alarm condition. SUMMARY OF THE INVENTION
The alarm device of the present invention incorporates both manual activation means and attitude- sensitive alarm activation means, and in the preferred embodiment, provides also for activation by external sensors.
In the preferred form of the invention, a battery operated radio transmitter is enclosed with the remaining componentry, in a small plastics case which is capable of being worn by means of a clip on the belt or pocket of a user. When activated, the transmitter radiates a signal which is coded to identify the particular alarm device. An audible alarm is also incorporated in the device, and this may suitably be a piezo-electric transducer. The alarm activation may occur instantly in the case of manual
action, or in timed stages in the case of attitude- sensitive actuation, and the audible alarm operates either in a continuous or a beeping mode for the purpose of distinguishing the alarm condition of the device. The device is also provided with a visual warning device such as an LED warning light, which may be coupled with the alarm driving circuitry.
For manual triggering of the device, a large and readily accessible alarm button is provided, and actuation of this button immediately activates the audible alarm in its continuous mode, and activates the transmitter, these being deactivated by being reset upon a subsequent operation of the alarm button.
As indicated above, the unit also incorporates an attitude-sensitive switch. Preferably this switch may selectively be operated either in a mode where the attitude-sensitive switch is operative, or in a mode where an alarm condition will only be produced by actuation of the alarm button. Time delay circuitry is incorporated to control the operation of the device when in its attitude-sensitive mode, as described below. BRIEF DESCRIPTION OF THE DRAWINGS
To facilitate an understanding of the construction and operation of the invention, reference will now be made to a proposed embodiment thereof, the operation of which is illustrated in the block diagram comprising the accompanying drawing. DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
As illustrated, the components of the alarm device
comprise an RF transmitter 10 which is provided with a transmitting antenna (not shown), a piezo-electric audible alarm device 11, a visible alarm device in the form of a light-emitting diode (LED) 14, a manual alarm button 12, and an attitude-sensitive switch 13 which may, for example, be a mercury switch. The alarm devices 11 and 14 are controlled by driving circuity 23.
The manual alarm button 12 is coupled with the alarm device 11 and the transmitter 10. In the normal mode of operation of the device, actuation of the button 12 results in the immediate operation of both the transmitter and the audible alarm. The audible alarm is maintained in a state of continuous operation by driver 23, and to facilitate location of the device and therefore of the person requiring assistance, this continues until the alarm condition is reset by a reset function 22 in response to a second operation of the alarm button 12. This condition is true also where the transmitter is activated in response to the attitude-sensitive or remote sensor activation of the device described below.
The LED indicator 14 provides an alternative local indication of the relevant alarm condition, and facilitates the observation of an alarm condition in conditions of high background noise. The attitude-sensitive switch 13 is operated when the device is horizontal or at a predetermined angle from the vertical, and is therefore actuated should the wearer collapse or should the device be left unattended in a horizontal position while in the attitude-sensitive
actuation mode. So that the attitude-sensitive mode may be selected and either temporarily or permanently turned off, the attitude-sensitive switch 13 is coupled with the alarm circuitry via logic circuitry responsiive to an on- off switch 15.
In the schematic form of the device illustrated, a 'tilt enable1 function 24 is controlled by counting and delay functions 25, 26 and 27 in response to operation of the on-off switch 15. A single operation and release of the switch 15, detected by counting function 25, actuates a battery-checking function 18, and if this reveals that the battery is in acceptable condition, the device is turned on with the tilt switch enabled, while at the same time the transmitter is actuated to transmit a signal indicative of the ON condition of the device in question, and the devices 11 and 14 are driven in a single "beep".
With the attitude-sensitive switch 13 enabled, activation of the attitude-sensitive switch 13 commences a first five second timing period by means of timing circuit 16. If the switch is returned to an unactivated position within that five second period, then no alarm condition is activated. If the attitude-sensitive switch 13 remains in its activated condition at the end of the five second delay provided by the timing circuit 16, then the audible alarm 11 is activated in a fast beeping mode, the LED 14 also being activated at that time. A further five second delay 17 is then commenced, and if during this period the switch 13 is deactivated, for example by the user, on becoming aware that he or she has accidentally caused the
alarm condition, returning the unit to its upright position, then the unit returns to its quiescent state. If the attitude-sensitive switch 13 remains in its activated condition at the end of the second five second delay, then the audible alarm 11 and the LED 14 are placed in a continous alarm mode and the transmitter 10 is activated. Preferably, to conserve power, the transmitter operates for only a short period after actuation., and for example may transmit a cycle of five repetitions of the identifying code of the particular device in question. The audible and visual alarms will then only be deactivated by a resetting operation of the manual alarm button 12.
Should the user need to leave the unit unattended for a short time, the attitude-sensitive function may be disabled by a double actuation of the on-off switch 15, detected by counting function 25 and signalled by two "beeps" of the devices 11 and 14. This disables the switch 13 for a period (suitably 60 seconds) determined by a time delay function 26, at the end of which the switch 13 is again enabled, this condition being signalled by a single beep operation of the devices 11 and 14.
Should it be desired to disable the attitude- sensitive function for an indefinite period, the on-off switch 15 is held down for a period of three seconds, detected by timing function 27 which disables the switch 13 and causes the driver 23 to operate the alarm devices 11 and 14 with three beeps.
In order that the alarm device may be coupled with
external alarm circuitry such as fire or smoke detectors, or intrusion warning devices, a sensor input circuit 20 is provided, with a pair of normally closed inputs 21. The sensor input circuitry 20 may be coupled with the alarm devices 11 and 14 and the transmitter 10, through one or more of the time delay circuits, in this embodiment the five second time delay circuit 17.
It will be appreciated that the present invention is not limited in its scope to the specific arrangement of the embodiment described, and that in its various' forms the functions may be achieved by hardware or software.