GB2499390A

GB2499390A - A telephone remote control system using the telephone ringtone to control an apparatus

Info

Publication number: GB2499390A
Application number: GB1202470.9A
Authority: GB
Inventors: Peter John Charles Spurgeon
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-02-14
Filing date: 2012-02-14
Publication date: 2013-08-21
Also published as: GB201202470D0

Abstract

A remote control system comprising: a calling device 1 (telephone); a receiving device 2 having an output (e.g. ringtone 5) prior to acceptance of the call; and a decoding device 3 that outputs at least one command signal (e.g. off signal 4 or on signal 5) prior to the call being accepted. Thus, when the telephone receiver 2 rings, its ringtone signal is decoded and output as a command to enable an apparatus to be operated. Aspects of the invention include the duration of the ringtone depending on the output required and the signal's function. The calling and receiving device may be connected by means of a telecommunications network, and part of the connection may be wireless. The output may operate an electrical contact, visual signal, audio alarm, digital stepping motor, electric motor and may be used in connection with a powered craft, used for surveillance or in a domestic property. Further aspects include the receiving device having a user programmable ringtone.

Description

A Long Distance Secure Remote Control System

Background

In a war situation the the remote operation of battlefield control devices, for communication of commands, surveillance equipment or aiming and firing of ordnance commonly uses short range remote control to avoid interception or replication by an enemy because long distance remote operation may be jammed or intercepted. Short range remote control has the disadvantage of having the operator within the danger zone. When the means makes use of code for teleprinters or even coded messages, the length of transmission is long enough to be intercepted, recorded and decoded using electronic listening apparatus. Some communications switrching apparatus uses tone switching apparatus (eg DTMF) because standards have been set for the frequencies to be used. However, these tones are present between the control apparatus and the remote equipment and are therefore capable of being intercepted, decoded and replicated by unauthorised personnel.. Radio control systems for civil use (eg eg radio controlled battery powered models) have a relatively small number of signalling frequencies that are set by the user inserting a crystal, or selecting the frequency in his controller and the remote device. The invention provides a system that utilizes cheaply priced telecommunication devices in such a way as to be undetectable and difficult to decipher since the data transmission or speech message does not take place. The system can also be used for remote surveillance operations when linked to a camera, eg by police forces. Any remote controlled vehicle or apparatus may be controlled by the system in air, land, sea or space. The apparatus so controlled can reply using a similar non-data communication. The invention is also capable of general application where it would have advantages of range and price over existing remote control systems since mobile phones are generally available and secondhand ones could be used at little cost.

Description

The calling controller consists of a telephone dialling device. When used with a conventional telephone network the remote reciever has a unique 'telephone number'. The controller dials the telephone number of the remote device and listens for the sound that indicates that the remote receiver is 'ringing'. The controller then stops the transmission after a short time - before the message about leaving a voice message. The remote system consists of a telephone receiver, a decoder and at least one command output. The command output can be latched until another command is recieved, latched until its 'off' command is recieved, held active for a set duration or a momentary signal. The remote telephone receiver has a ringtone for output to a loudspeaker (preferably produced by a programmable audio file).. The audible ringtone output may be disabled and the electrical signal connected to a decoder unit. When the telephone reciever 'rings' its ringtone signal is decoded and output as an audio, visual, electrical or mechanical 'command' output to enable features of an apparatus to be operated manually or automatically. Since the telephone number of the remote device is unique and its ringtone file and function are secure in the remote device itself then any surveillance will have difficulty in determining the preence, function or position of the remote apparatus. The fact that a 'telephone call' is made but terminated before any audio message is transmitted makes the communication virtually invisable. After a number of uses the SIM card and ringtone file of the remote device can be changed to make the operation and location of the remote device even more secure. There are a number of ways that the 'Caller Display' possibilities can be disabled by the caller or in the receiver.

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Detailed Description

The remote controller can issue one or more commands' to the remote device. These command signals may be for the purpose of implementing Reset, Off, On, Forward, Reverse, Up, Down etc and Connect in the remote apparatus - the connect output reproduces the action of a human lifting the receiver of a telephone in order to engage in conversation - such action may start a fax receiver or a recording apparatus or an automatic reply machine. The command is issued by signalling to the Remote for a certain period of time so that the remote device outputs that part of its ringtone file by a duration appropriate to the desired command. The system can be used for such simple operations of switching a red or green light on (like traffic lights) or of controlling a camera, remote vehicle or gun. The system can be made more or less complex according to the electronics included in the controlling and remote device. The ringtone file may contain intervals with single frequency signals or of two or more frequency signals at the same time. The ringtone file may contain sections of signals that are amplitude modulated or frequency modulated. The ringtone file may contain frequencies formed of sinusoidal waves, square waves or sawtooth waves. A method used for some telephone dialling apparatus uses the DTMF system where 16 codes are represented by 16 different pairs of known frequencies that may be represented in a 4 row and 4 column matrix where each row has the same low frequency and each column has the same high frequency. 1 2 3 A Row freq = 697 Hz 4 5 6 B 770 Hz

7 8 9 C " 852 Hz

* 0 # D " 941 Hz

1209 1336 1477 1633 (column frequencies)

Such a standardized system is easy to implement and to test using standard electronic components and modules. The range of frequencies in the ringtone file is preferably between 300 and 3000 Hz in order that the receiver output is able to accurately reproduce the ringtone.

In figure la a remote system is shown according to the invention that willswitch an equipment off or on. The caller telephone 1 dials the code for the remote receiver telephone 2 and listens for the tone 6 that indicates the receiver telephone is ringing . The caller allows the ringing to continue for a predetermined time according to whether he wishes the decoder 3 to output an off signal 4 or an on signal 5. These outputs could perform any function. There is a connection 6 between the caller telephone 1 and a telephone network exchange device 7. The connection 17 to the remote receiver telephone maybe conducting cables, fibre optics or wireless. Upon being polled by the caller telephone 1 the remote receiver telephone 2 emits its ringtone signal 5. Figure lb shows a simple ringtone, consisting of periods of audio frequency 8 and intermediate quiet times, the times 9 at the start of the first frequency burst, time 10 of the second frequency burst and time 11 of the third frequency burst are used by the decoding device, time 16 is after the active decoding times. Figure lc shows the flowchart of the decoder 3 as an amplitude detector 3a, a timer 3b and latching output relays 3c and 3d. The detector 3a outputs a pulse 12 at the start of the ringtone 9 and this pulse 12 starts the timer 3b which outputs pulses 13 14 and 15 at times 9 10 and 11 if signal is present in the ringtone at those times.

Relay 3c latches any signal 14 to produce an OFF output 4 and relay 3d latches any signal 15 to produce the ON output 5. The operation outlined as above will result in an OFF output if the ringtone 5 terminates between times 10 and 11 and a mementary OFF followed by an ON output if the ringtone 5 is terminated between times 11 and 16. This simple system can be extended to more latched outputs by use of a timer having more set times and a ringtone with

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more frequency bursts. Many logic connections are not shown including one to reset latching relay 3c when output 5 is present and one to reset the detector 3a and timer 3b when the signal 17 has been terminated.

Figure 2 shows a ringtone including different frequency portions and a decoder having filters to decode and act upon the sequence. A commercially available system uses the DTMF dual tone signalling system so that the ringtone file could include parts that are easily encoded and decoded by a standard integrated circuit. In all cases a number of'fail-safe' strategies can be used, for example the first part of the ringtone file 8 at time 9 always resets the system outputs due to the tuned filter 21 that only responds to the frequency present in the bursts 8. The DTMF system 22 responds to the pairs of frequencies present at times 18 19 and 20 , latching the relevant output unless it is reset by another pulse from the filter 21. Thus by terminating the ringtone during a dual frequency part 18 19 or 20 the corresponding output 23 24 or 25 will remain active until the next ringtone 5 begins. The ringtone of a sytem can include alternate reset bursts and DTMF bursts to activate up to 16 outputs, one at a time with this simplified arrangement that could correspont to commands such as OFF FORWARD REVERSE LEFT RIGHT UP DOWN STOP START ANSWER. IC8870 is a typical DTMF decoder IC or a microcomputer analogue input may be used and a programme to perform a Fourier analysis to decode the frequencies present. Keypads with a DTMF output are readily available DTMF an encoder kit with 16 key Keypad with single tone option and TX keying is available that uses an HT9200 IC. this could be easily used to produce audio files of the 16 dual frequencies and 8 single frequencies that can then be compiled into ringtone files as required using standard audio editing software such as Audacity (TM). The controller and remote devices of the system can be powered by mains, battery, energy storage or electrical generators. The ringtone file may be stored in the built-in memory of the remote receiver or in a memory device such as a sim card and may be up to 2 minutes if played in full.

By using a microprocessor and memory storage system many different commands can be decoded, each one being separated from the next by a resetting frequency burst. However, it is only the final command before the ringtone is terminated that should be decoded and implemented. The ringtone signal is stored in a last-in first out register, the register being played into the decoder after a sufficient length of time for the sequence to be complete. The final command in the register is then decoded and implemented.. The register can be stored and retrieved under microprocessor control in a classic Stack arrangement and the intermediate Reset signals can clear the top of the stack in readiness for the next command until a command is reached with no following Reset signal. The ringtone file may contain several complete sets of commands, some of which may set the microprocessor programme in such a way as to decode new commands differently, for example setting the duration of a Left or Right direction oput-put.

Since the ringtone file can be manipulated very accurately it can consist of known numbers of peaks and troughs, the decoding circuit then counting the number of them in order to decode particular commands.

A further level of security can be added by recording the ringtone file from human speech and including a speech recognition means in the decoding device. Speech recognition can be set to respond only to one person's voice pattern so it becomes difficult for an unauthorised person to record the ringtone file.

Individual components shown in the drawings are not limited to use in their drawings and they may be used in other drawings and in all aspects of the invention.

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Claims

1. A remote control system comprises of a calling device, a receiving device having an output prior to acceptance of the call and a decoding device that outputs at least one command signal prior to the call being accepted.

2. A remote control system according to claim 1 having a receiving device with a user-programmable ringtone.

3. A remote control system according to claim 1 and any one of the previous claims in which the calling device has means to terminate the output of the ringtone output by the receiving device at a desired time period from the start of the ringtone output, such portion of the ringtone being decoded to output a command according to the contents of that part of the ringtone.

4. A remote control system according to claim 1 and any one of the previous claims in which the calling and receiving device are connected by means of a telecommunications network.

5. A remote control system according to claim 1 and any one of the previous claims in which part of the connection between the calling and the receiving device is wireless.

6 A remote control system according to claim 1 and any one of the previous claims in which at least one of the command signals causes the receiver to acknowledge a connection to enable a two-way communication to take place between the calling device and the recieving device.

7. A remote control system according to claim 1 and any one of the previous claims in which the ringtone includes at least two tone periods and at least one silence period.

8. A remote control system according to claim 1 and any one of the previous claims in which the ringtone output is disconnected from its loudspeaker.

9. A remote control system according to claim 1 and any one of the previous claims in which the ringtone includes at least two different frequencies.

10. A remote control system according to claim 1 and any one of the previous claims in which the ringtone includes at least one period of simultaneous frequencies.

11. A remote control system according to claim 1 and any one of the previous claims in which the ringtone includes at least one period of DTMF signalling frequencies.

12. A remote control system according to claim 1 and any one of the previous claims in which the ringtone output is decoded by an apparatus having frequency filters.

13. A remote control system according to claim 1 and any one of the previous claims in which the ringtone output is decoded by a programmable digital device.

14. A remote control system according to claim 1 and any one of the previous claims in which the ringtone output is decoded by a DTMF decoding device.

15. A remote control system according to claim 1 and any one of the previous claims having an output to operate an electrical contact.

16. A remote control system according to claim 1 and any one of the previous claims having an output that operates a visual signal.

17. A remote control system according to claim 1 and any one of the previous claims having an output that operates an audio alarm.

18. A remote control system according to claim 1 and any one of the previous claims having an output that operates an analogue mechanical actuator.

19. A remote control system according to claim 1 and any one of the previous claims having an output that operates a digital stepping motor actuator.

20. A remote control system according to claim 1 and any one of the previous claims having an output that operates an electric motor.

21. A remote control system according to claim 1 and any one of the previous claims having an

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output that operates a trigger.

22. A remote control system according to claim 1 and any one of the previous claims used in connection with a powered craft.

23. A remote control system according to claim 1 and any one of the previous claims used for surveillance.

24. A remote control system according to claim 1 and any one of the previous claims used in a domestic property.

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