GB2214675A - Programmable beacon - Google Patents

Abstract

A programmable flashing beacon device for identification and location purposes which includes a shift register in which a series of on/off control pulses can be stored by means of a manually operable switch. The pulses are then continuously recirculated repeating the stored program of flashes until power is switched off. <IMAGE>

Description

PROGRAMMABLE BEACON The present intention relates to apparatus for emitting a Programmable sequence of flashes of visible or infra-red light for identification and location purposes. During covert operations by Police and Security Forces, it is frequently necessary to identify personnel, zones and equipment in a manner not obvious to the casual observer.

Apparatus is known which emits flashes of infra-red light according to a fixed sequence, such pulses being invisible to the naked eye but readily visible to the night-vision equipment used by the Police and Armed Forces.

A disadvantage of existing apparatus is that the flash rate and sequence is limited to a few preset sequences fixed during manufacture.

A requirement exists for a device capable of being simply programmed to emit any type, sequence, and length of flash as circumstances require.

According to the present invention there is provided apparatus consisting of a light source, electronic control means, and data entry means; such control means being capable of recording a sequence of on and off conditions entered using the data entry means and of subsequently reproducing the same sequence of turning the light source on and off.

Preferably, the light source consists of a plurality of light emitting diodes.

Preferably, the data entry means consists of a push-button switch.

A particular embodiment of the present invention will now be described by way of example, in which: Figure 1 shows a block diagram of the electronic control means.

Figure 2 shows the outward appearance of the device and associated power source.

Referring to Figure 1, the reset circuit 1 produces a signal which is used to set latch 4 and simultaneously to cIear the contents of shift register 3.

When push button 6 is pressed the signal at the Q output of latch 6 is applied to data input of shift register 3 where it is clocked into successive locations by clock source 2. If the button 6 is released, the opposite logic level will be clocked into shift register 3.

Typically the length of the shift register 3 and the clock speed will be selected such that several clock transitions occur per second, resulting in the on or off state of the switch being reflected in the data stored in the shift register 3. If for example the switch 6 is pressed and released in the pattern corresponding to the Morse Code Letter 'S' then a sequence of Logic 1 levels will be stored each with a sequence of Logic 0 Levels following it.

The number of Logic 1 Levels consequently stored will be determined by the mount of time the switch 6 is held down for each part of the code.

When the entered data fills the sheet register 3, it appears at the output where it is applied to output driver 5 such that the Logic 1 Levels clocked into the shift register whilst the switch 6 was depressed turn the light source 7 on.

The first Logic 1 Level appearing at the output driver is applied to latch 4, resetting it and removing the Logic 1 Level from Switch 6. Further depressions of switch 6 will have no effect on device operation.

Data appearing at the output of Shift Register 3 is recirculated internally and thus the cycle repeats until power is removed.

The effective result of this process is that a pattern of ON/OFF states entered by depressing the switch in a desired sequence is stored and repetitively drives the Light Source ON and OFF in the same pattern.

Figure 2 shows a particular embodiment in which Switch 8 and Light Sources 10 are mounted in Box 9 such that they protrude through apertures.

Terminals 11, 12 make electrical connection and physically anchor the device to Battery 13.

Claims (9)

1. A programmable beacon device including a light source, means for storing a sequence of on/off control signals, and manually operable means for programming a desired sequence of on/off control pulses into the storage means, whereby the light source can be automatically operated in accordance with the said programmed sequence.

2. A beacon device according to claim 1 in which the light source comprises at least one light-emitting diode.

3. A beacon device according to claim 1 or claim 2 in which the program entry means includes a switch device supplied with preset logic levels.

4. A beacon device according to any preceding claim in which the storage means comprises a shift register.

5. A beacon device according to claim 4 further comprising a source of clock pulses arranged to clock the logic level from the switch device into the shift register.

6. A beacon device according to claims 3, 4 and 5 in which the source of clock pulses, the shift register and the switch device are so interconnected that the operator can control the length of each on or off period by holding or releasing the switch device for a corresponding period of time, so that the contents of the shift register reflect the on/off periods of the switch.

7. A beacon device according to claim 6 further comprising latch means which is arranged to change the logic level supplied to the switch device, when the shift register is full, whereby further operation of the switch device has no effect on the stored program.

8. A beacon device according to any preceding claim in which the stored program is arranged to recirculate continuously so as to operate the light source repeatedly until power is removed from the circuit.

9. A beacon device substantially as herein described with reference to the accompanying drawings.