WO2003063091A1

WO2003063091A1 - Knocking activated device and method for operating an electromechanical device responsive to a device control signal

Info

Publication number: WO2003063091A1
Application number: PCT/CA2002/000069
Authority: WO
Inventors: André LAROCHE
Original assignee: 9068-7005 Quebec Inc.
Priority date: 2002-01-18
Filing date: 2002-01-18
Publication date: 2003-07-31
Also published as: EP1468405A1

Abstract

A knocking activated device (10) and method for operating an electromechanical device that is responsive to a device control signal. The knocking activated device (10) amplifies a signal generated by a vibration transducer (18) according to an initial gain level that is momentarily decreased in response to a gain control signal received by a gain adjustable amplifier (15). Data that is representative of predetermined groups of knocks is stored in me mory (30), with each group not exceeding a predetermined maximum number of knocks. A microprocessor (28) discriminates the amplified signal into groups of knocks and carries out a comparison with the data stored in a memory (30) to produce the device control signal if the groups of knocks match the predetemined groups of knocks, whereas it generates the gain control signal if one group of knocks contains a number of knocks exceeding the predetermined maximum number of knocks.

Description

KNOCKING ACTIVATED DEVICE AND METHOD FOR OPERATING AN ELECTROMECHANICAL DEVICE RESPONSIVE TO A DEVICE CONTROL

SIGNAL

FIELD OF THE INVENTION

The present invention relates to a knocking activated device and a method for operating an electromechanical device, particularly a locking mechanism of a vehicle.

BACKGROUND

The present invention is an improvement over Canadian patent application No. 2,300,021 (Laroche) which discloses a knocking activated device and method for operating an electromechanical device, such as an electric lock of a vehicle. The knocking activated device unlocks the vehicle's electric lock when a user knocks on the vehicle's window a predetermined number of times according to a predetermined code. One drawback of the knocking activated device is that extraneous noises can affect its operation. Indeed, noise coming from the radio and/or the motor engine of the vehicle can be picked up along with the user's knockings on the windows, leading to erroneous readings by the knocking activated device, when in fact a user may have correctly provided the right code.

There is therefore a need for an improved knocking activated device that is less sensitive to extraneous noise during its operation.

SUMMARY

An object of the present invention is to provide a knocking activated apparatus having an improved performance in a noisy environment. According to the present invention, there is provided a knocking activated device for operating an electromechanical device responsive to a device control signal, comprising: a vibration transducer for generating a signal in response to vibrations; a gain adjustable amplifier for amplifying the signal generated by the vibration transducer according to an initial gain level that is momentarily decreased in response to a gain control signal, and generating an amplified signal; storing means for storing data representative of predetermined groups of knocks, each of the predetermined groups containing a predetermined maximum number of knocks; a user operable interface for changing the data stored in the storing means; discriminating means for discriminating the amplified signal into groups of knocks by recognizing that successive knocks that are separated from each other by less than a predetermined time period belong to a same group of knocks, and that successive knocks that are separated from each other by at least the predetermined time period belong to different groups of knocks; and comparing means for carrying out a comparison between the groups of knocks obtained from the discriminating means with the data stored in the storing means to produce the device control signal if the groups of knocks obtained from the discriminating means match the predetermined groups of knocks, or generate the gain control signal if one group of knocks among the groups of knocks obtained from the discriminating means contains a number of knocks exceeding the predetermined maximum number of knocks.

According to the present invention, there is also provided a method for operating an electromechanical device responsive to a device control signal, comprising the steps of: (a) storing data representative of predetermined groups of knocks through a user operable interface, each of the predetermined groups of knocks containing a predetermined maximum number of knocks;

(b) once step (a) has been performed at least one time, detecting vibrations and generating a signal in response to the vibrations;

(c) amplifying the signal generated in step (b) according to an initial gain level that is momentarily decreased in response to a gain control signal, and generating an amplified signal;

(d) discriminating the amplified signal into groups of knocks by recognizing that successive knocks that are separated from each other by less than a predetermined time period belong to a same group of knocks, and that successive knocks that are separated from each other by at least the predetermined time period belong to different groups of knocks; and

(e) comparing the groups of knocks obtained in step (d) with the data stored in step (a) to (i) produce the device control signal if the groups of knocks obtained in step (d) match the predetermined groups of knocks; or to (ii) generate the gain control signal if one group of knocks among the groups of knocks obtained in step (d) contains a number of knocks exceeding the predetermined maximum number of knocks.

The invention as well as its numerous advantages will be better understood by reading the following non-restrictive description of possible embodiments made in reference to the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a perspective view of a knocking activated device according to a preferred embodiment of the present invention;

Figure 2 shows a circuit diagram of a knocking activated device according to a preferred embodiment of the present invention; and Figures 3A and 3B show a flow diagram of a method for operating an electromechanical device according to a preferred embodiment of the present invention.

DETAILLED DESCRIPTION OF THE INVENTION

Referring to Figures 1 and 2, there is illustrated a knocking activated device 10 for operating an electromechanical device, such as an electric lock of a vehicle (not shown), that is responsive to a device control signal.

The knocking activated device 10 is provided with a vibration transducer, which is preferably embodied by a microphone 14, for generating a signal in response to vibrations. These vibrations can be produced for example by knockings on a window of a vehicle. Furthermore, it will be understood by those skilled in the art that these vibrations could also be produced by clapping one's hands, by playing prerecorded sounds, or by any other suitable means.

As is illustrated in Figure 2, the knocking activated device 10 has a gain adjustable amplifier 15, which is preferably embodied by two cascaded amplifiers (shown enclosed in dotted lines), for amplifying the signal generated by the vibration transducer 14. The signal received at input 11 of the amplifier 15 is amplified according to an initial gain level that is momentarily decreased in response to a gain control signal. The gain adjustable amplifier 15 generates an amplified signal at output 17. As will be apparent to those skilled in the art, other equivalent circuit designs can be used instead of the gain adjustable amplifier 15 that is illustrated.

The knocking activated device 10 also includes a storing system, which is preferably embodied by a memory flash 30, for storing data representative of a predetermined groups of knocks. Each of the predetermined groups of knocks stored in the memory flash 30 contains a predetermined maximum number of knocks, which is preferably of nine knocks.

The knocking activated device 10 is also provided with a user operable interface, which preferably includes a programming button 16 and a LED 18, for changing the data stored in the storing system or memory flash 30.

The knocking activated device 10 has a discriminating system, preferably embodied by a microprocessor 28 provided with a software, for discriminating the amplified signal into groups of knocks by recognizing that successive knocks that are separated from each other by less than a predetermined time period belong to a same group of knocks, and that successive knocks that are separated from each other by at least the predetermined time period belong to different groups of knocks. Preferably, the predetermined time period is of one second and at most of ten seconds.

The knocking activated device 10 also has a comparing system, preferably also embodied by the microprocessor 28 provided with software, for carrying out a comparison between the groups of knocks obtained from the discriminating system with the data stored in the storing system or memory flash 30 to produce the device control signal at output 23 of the microprocessor 28 if the groups of knocks obtained from the discriminating system match the predetermined groups of knocks. Alternatively, the comparing system generates the gain control signal if one group of knocks among the groups of knocks obtained from the discriminating system contains a number of knocks exceeding the predetermined maximum number of knocks, which is typically of nine.

For example, if ten or more knocks are detected by the discriminating system within one group of knocks, then the gain control signal is generated at one of the outputs 25, 27, 29 of the microprocessor 28 to decrease the initial gain level gain of the gain adjustable amplifier 15.

Preferably, the gain adjustable amplifier 15 is responsive to successive gain control signals occurring within a predetermined period of time for momentarily further decreasing the initial gain level by steps up to a predetermined limit. In the illustrated example in Figure 2, this means that the initial gain control signal is first generated at output 29 of the microprocessor 28 using resistances R11 of 33 kOhm and R3 of 150 kOhm, thereby setting the adjustable gain amplifier 15 with an initial gain of 80. Thereafter, if ten or more knocks are detected by the discriminating system, then a successive gain control signal is generated at output 27 of the microprocessor 28 using resistances R12 of 120 kOhm and R3, momentarily decreasing the initial gain level down to 33. During a continued operation of the knocking activated device 10, if ten or more knocks are once again detected by the discriminating system, then another gain control signal is generated at output 25 of the microprocessor 28 using resistances R5 of 270 KOhm and R3, further momentarily decreasing the gain level down to 23. The gain level can be further decreased down to 15 by using only resistance R3.

In a typical example, the predetermined groups of knocks that are stored in the memory flash 30 correspond to a single numbered sequence of at least four groups of knocks, such as 4, 5, 9, 8, providing almost ten thousand possible combinations. The memory flash 30 can store up twelve groups of knocks, providing billions of possible combinations

In another preferred embodiment of the present invention, the predetermined groups of knocks that are stored in the memory flash 30 may contain two series of predetermined groups of knocks that can unlock the electromechanical device instead of only one as mentioned above. With such a configuration, the comparing system uses one of the two series for a current comparison and the other series for a next comparison if result of the current comparison is positive. In other words, the right code for opening a door of a vehicle alternates between two right possibilities. For example, the first code may be 4, 5, 9, 8 and the second code 7, 5, 3, 4. Thereby, when the user unlocks the door with the first code, the knocking activated device 10 only accepts the second code the next time a user tries to unlock the door. Once the door is unlocked with the second code, the knocking activated device switches back to the first code, and so on and so forth. This increases security in case someone is eavesdropping and would use the same code to unlock the vehicle. Of course, one could also have more than three alternating codes for increased security, but this could unduly burden the user as he would have to remember several codes and also remember the sequence in which these were entered.

The knocking activated device 10 may be provided with a noise filter connected between the microphone 14 and the amplifier 15. The noise filter can be embodied by capacitance C5 of 0.1 μF and resistance R6 of 100 KOhm. This filter eliminates some of the noise that is picked up by the microphone in order to keep frequencies typically between 1000 and 2000 Hz.

Preferably, the comparing system can be provided with an error detection system for temporarily shutting down operation of the knocking activated device 10 if the group of knocks obtained from the discriminating system do not match the predetermined groups of knocks and if each of the groups of knocks obtained from the discriminating system contains a number of knocks that is equal to or lower than the maximum number of knocks. For example, the error detection system can shut down the operation of the knocking activated device 10 for about ten seconds so that a user will have to wait at least ten seconds to try his code again. This feature increases the security of the knocking activated device 10 as an unauthorized user could not easily try several combinations in a limited amount of time. Preferably, the electromechanical device is part of a vehicle, and the microprocessor 28 has an input 31 connected to an ignition key cable 24 of the vehicle for automatically generating the gain control signal when the ignition key is actuated. Therefore, when a user starts his vehicle, the gain level of the amplifier is automatically reduced. This feature is useful as the motor of the vehicle and its radio may be a source of unwanted noise that can affect the operation of the knocking activated device 10.

Preferably, the knocking activated device 10 includes a voltage regulator 38 having an input for connection to a power source 44, such as the battery of a vehicle, and an output 46 for supplying the necessary power to the different components of the knocking activated device 10, such as the microphone 14 and the microprocessor 28. The voltage regulator may be a 5 V voltage regulator and the power source may be a 12 V battery of a vehicle. A protection diode 40 is preferably used between the voltage regulator 38 and the 12 V battery in case the battery cables 22 are inadvertently inverted upon connection by a user. The microphone 14, which is preferably an electret microphone, is powered by a 5 V power supply 46, or alternatively supplied by the output of the voltage regulator 38.

Preferably, the knocking activated device 10 further comprises an output interface, such as an optocoupler 42, having an input connected to the output 23 of microprocessor 28 and outputs, such as cables 26, for operating the electromechanical device.

According to a preferable application of the present invention, the knocking activated device 10 is used for operating the locking mechanism of a vehicle door by knocking on the window glass thereof. Preferably, the knocking activated device 10 further comprises a Velcro™ attachment 20 for fixing the knocking activated device 10 inside the vehicle. The Velcro™ attachment 20 is provided on back of the knocking activated device 10 and measures about one square inch. Of course, other means for attaching the device 10 inside the vehicle may be used instead of the Velcro™ attachment, for example a screw and bolt arrangement. Furthermore, the electric locking mechanism should not be limited to that of a vehicle, but should be construed to cover any locking mechanism, such as the one of a the door of a house. In the above example, the device 10 is hidden under the dashboard of the vehicle so that it can be easily removed for changing its codes or data as it will be further explained.

Furthermore, the output for operating the electromechanical device is preferably embodied by a pair of cables 26, which are connected to the electric locking mechanism of the vehicle. Another cable 24 connects an ignition key of the vehicle to the microprocessor 28 for activation of the knocking activating device 10. In the case of older vehicles, the electric locking mechanism may be replaced, for example, by an electromagnetic or electromechanical relay (not shown).

Preferably, the programming button 16 is connected to the microprocessor 28 for setting the device 10 into a programming mode. The LED 18 which is responsive to the button 16 is provided for interacting with the user during a programming of the device 10. The LED 18 may be of a bicolor (red and green) type.

Referring back to Figure 1, the circuit of the knocking activated device 10 is preferably housed in a small box 12 made of black colored plastic similar to remote controlled car starters. The box 12 has a size of approximately 2" high x 1.25" wide x 0.5" deep.

Referring now to Figures 3A and 3B, there is shown a flow diagram of a preferred embodiment of a method, according to the present invention. Essentially, the method for operating an electromechanical device responsive to a device control signal, comprises the steps of:

(a) storing data representative of predetermined groups of knocks through a user operable interface 16, each of the predetermined groups of knocks containing a predetermined maximum number of knocks, step (a) being preferably performed by operation step 48;

(b) once step (a) has been performed at least one time, detecting vibrations and generating a signal in response to the vibrations, step (b) being preferably performed by operation step 50; (c) amplifying the signal generated in step (b) according to an initial gain level that is momentarily decreased in response to a gain control signal, and generating an amplified signal, step (c) being preferably performed by operation step 52;

(d) discriminating the amplified signal into groups of knocks by recognizing that successive knocks that are separated from each other by less than a predetermined time period belong to a same group of knocks, and that successive knocks that are separated from each other by at least the predetermined time period belong to different groups of knocks, step (d) being preferably performed by operation step 54; and (e) comparing the groups of knocks obtained in step (d) with the data stored in step (a) to (i) produce the device control signal if the groups of knocks obtained in step (d) match the predetermined groups of knocks; or to (ii) generate the gain control signal if one group of knocks among the groups of knocks obtained in step (d) contains a number of knocks exceeding the predetermined maximum number of knocks, step (e) being preferably performed by operation steps 56, 58, 60 and 62.

In a typical scenario of use of the knocking activated device 10, a user has forgotten his keys inside his vehicle, the doors are locked, the motor engine is running and the radio is on. In a prior version of the knocking activated device this scenario could have been a problem as the noises produced by the motor engine and the radio of the vehicle could have being counted as additional knocks at the time the user knocks in his code, thus causing the knocking activated device 10 to consider it to be a wrong code. The present invention solves such a problem, by determining at operation step 56 that one of the groups of knocks contains a number of knocks exceeding the predetermined maximum number of nine knocks. If such is the case, the gain control signal is generated at operation step 58 and the method loops back for processing other sequences of knocks at operation steps 52 and 54. As a consequence, in above step (c), the initial gain level can be momentarily further decreased by steps up to a predetermined limit in response to successive gain control signals occurring within a predetermined period of time.

The gain level of the gain adjustable amplifier 15 can thus be manually decreased by the user when he intentionally knocks ten times on the window of the vehicle if he considers that the noise level is too high. In any case, the gain level can be automatically reduced when noises produced by the motor engine or the radio of the vehicle are counted as knocks at the time the user is knocking his code on the window. Indeed, this leads the knocking activated device 10 to determine that one group of knocks has exceeded the predetermined number of nine knocks.

As the gain level is either manually or automatically decreased by steps in the manner explained above, the user may have to knock a bit harder on the vehicle's window because the sensibility of the knocking activated device 10 is reduced. The gain level may be decreased in four steps starting at 80, and then going down to 33, 23 and 15. Once the knocking activated device 10 does not detect any knockings for a certain period of time, it sets its gain level back to the initial gain level. Preferably, the above step (b) includes the step of filtering noises in the signal generated in step (b), at operation step 50. As explained before this can be achieved by use of a small RC filter.

Preferably, step (e) includes the step of temporarily shutting down operation of the knocking activated device 10 for about ten seconds if the groups of knocks obtained from the discriminating system do not match the predetermined groups of knocks and if each of the groups of knocks obtained from the discriminating system contains a number of knocks that is equal to or lower than the maximum number of knocks. This step is preferably performed by operation step 64 in the flow diagram.

Because once the vehicle's motor engine is started it can create undesirable noise, it may be advantageous to include in above step (e) the step of automatically generating the gain control signal when the ignition key of the vehicle is actuated.

As was explained above, when the predetermined groups of knocks stored in step (a) contain two series of predetermined groups of knocks, then the above step (e) can include the step of using one of the two series for a current comparison and the other series for a next comparison if result of the current comparison is positive, as illustrated in operation step 66.

Preferably, above step (a) includes the steps of: (i) activating the user operable interface; and

(ii) once step (i) has been performed, entering data through the user operable interface for storing or changing the data.

Preferably, step (a) also comprises the steps of: (i) pressing the programming button 16 of the knocking activated device for a predetermined amount of time; and

(ii) once step (i) has been performed, pressing and depressing the programming button 16 a multiple number of times in a predetermined period thereby storing or changing the data.

Furthermore, an important object of the present invention is to provide an apparatus and method which allows the unlocking of a door, or similar mechanism, without a key, numerical keyboard, remote control device or any other portable object of the sort.

Referring back again to Figures 1, 2, 3A and 3B, we will show the simplicity of operation of the invention by way of example. First, the knocking activated device 10 is mounted inside a vehicle. The microphone 14 is placed near the window of the vehicle. A user knocks on the window in a predetermined or coded manner to produce knockings. The knocking activated device 10 discriminates the knockings into groups of knocks, ensuring that each group of knocks is separated by a period of one to ten seconds. It also recognizes that the knocks that are separated by less than one second belong to the same group of knocks.

For example, if the user code is 5, 3, 7, 6 then a user must knock five times on the window, then wait for a minimum of one second or a maximum of ten seconds before going on to the next number in the above sequence. The user then knocks three more times on the window while ensuring that the time difference between each knock in this second group is less than one second, and so on and so forth for the other numbers. Thereafter, a control signal is sent by the knocking activated device 10 to the electric locking mechanism of the vehicle and the doors of the vehicle are unlocked. If a code is incorrectly entered, the device 10 may switch to the error mode as explained above. A series of three green flashes by the LED 18 will indicate that the device 10 is ready to receive a new code.

For visualizing the user code on the knocking activated device 10, the user inserts a key in the ignition of the vehicle. This activates microprocessor 28 via cable 24. The user may then see the user code by pressing the programming button 16 once for less than three seconds. A series of flashes of the green LED 18 indicates a first number of the user code and a flash of the red LED 18 indicates that the next number of the user code will be flashed subsequently by the green LED 18. This is repeated a few times. The device 10 will then come out of this mode automatically.

For programming of a new user code, the user inserts the key in the ignition of the vehicle. The user must hold down the programming button 16 for at least three seconds and then the red LED 18 stars flashing. The user must then release the button 16 and then press it again in a similar way as if he was knocking on the window. The green LED 18 will flash with each new entry and the delay between another sequence will be signaled by the red LED 18. Thereafter, if no other entry is made within five seconds, a new user code will be automatically stored and the device 10 will automatically come out of this mode. A minimum sequence of four numbers and a maximum sequence of twelve numbers between one and nine can be entered to be recognized as a valid user code. If not, the device 10 will reject such a code by flashing the red LED 18 five times, it will keep the old user code and will come out of this mode automatically.

Another issue to be addressed herein concerns the communication protocol between the knocking activated device 10 and the system operating the electromechanical device. As is known by those skilled in the art, certain types of vehicles have a central computer system with an input, which is typically dedicated to the unlocking of the doors of the vehicle. This input is especially used for receiving commands from an auxiliary system, which is usually installed separately. For example, the auxiliary system can include a remote starter system with an alarm system and a remote unlocking function that is provided on a remote control.

As there is no single standard protocol established by the automobile manufacturers with respect to the communication protocol that regulates data transmission at the input of the central computer system, the auxiliary system needs to be specifically programmed by an installer in order to adapt it to the particular communication protocol. There exist at least three different types of communication protocols that are currently being used in different types of vehicles.

Therefore, those skilled in the art will understand that the knocking activated device 10 may be provided with a special programming mode for selecting the proper protocol to be used by the knocking activated device 10. This communication protocol is transmitted, for example, through the output 23 of the microprocessor 28.

In order to start the protocol selection mode of the knocking activated device 10, the programming button 16 can be depressed for about 13 seconds. Thereafter, a flashing green light emitted by the LED 18 will indicate which protocol is selected by flashing either one, two or three times. Every time that the programming button 16 in depressed during this mode, one can switch between the different protocols. Once the appropriate protocol is chosen, and a time period of about three seconds has elapsed, the knocking activated device stores the proper protocol to use in the memory flash 30 and exits the protocol selection mode. The above method therefore preferably includes the steps of:

(i) depressing a programming button 16 of the knocking activated device 10 for a predetermined amount of time; and (ii) depressing the programming button 16 a multiple number of times in a predetermined period for storing or changing a data communication protocol.

In case that the knocking activated device 10 is incompatible with the central computer system of a vehicle, the optocoupler 42 can provide sufficient power and be connected instead to an electromechanical relay (not shown), which in turn is connected to the lock activating cables 26 of the vehicle.

Although the present invention has been explained hereinabove by way of a preferred embodiment thereof, it should be understood that the invention is not limited to this precise embodiment and that various changes and modifications may be effected therein without departing from the scope or spirit of the invention.

Claims

CLAIMS:

1. A knocking activated device for operating an electromechanical device responsive to a device control signal, comprising: a vibration transducer for generating a signal in response to vibrations; a gain adjustable amplifier for amplifying the signal generated by the vibration transducer according to an initial gain level that is momentarily decreased in response to a gain control signal, and generating an amplified signal; storing means for storing data representative of predetermined groups of knocks, each of the predetermined groups containing a predetermined maximum number of knocks; a user operable interface for changing the data stored in the storing means; discriminating means for discriminating the amplified signal into groups of knocks by recognizing that successive knocks that are separated from each other by less than a predetermined time period belong to a same group of knocks, and that successive knocks that are separated from each other by at least the predetermined time period belong to different groups of knocks; and comparing means for carrying out a comparison between the groups of knocks obtained from the discriminating means with the data stored in the storing means to produce the device control signal if the groups of knocks obtained from the discriminating means match the predetermined groups of knocks, or generate the gain control signal if one group of knocks among the groups of knocks obtained from the discriminating means contains a number of knocks exceeding the predetermined maximum number of knocks.

2. The knocking activated device according to claim 1 , wherein the gain adjustable amplifier is responsive to successive gain control signals occurring within a predetermined period of time for momentarily further decreasing the initial gain level by steps up to a predetermined limit.

3. The knocking activated device according to claim 1, wherein the vibration transducer comprises a microphone connected to a noise filter.

4. The knocking activated device according to claim 1, wherein the predetermined maximum number of knocks is nine.

5. The knocking activated device according to claim 1, wherein the predetermined time period is of one second.

6. The knocking activated device according to claim 1, wherein the comparing means further comprises an error detection means for temporarily shutting down operation of the knocking activated device if the groups of knocks obtained from the discriminating means do not match the predetermined groups of knocks and if each of the groups of knocks obtained from the discriminating means contains a number of knocks that is equal to or lower than the maximum number of knocks.

7. The knocking activated device according to claim 6, wherein the error detection means shuts down the operation of the knocking activated device for about ten seconds.

8. The knocking activated device according to claim 1, wherein the discriminating means and the comparing means are embodied by a microprocessor provided with a software, the storing means is embodied by a memory flash that is connected to the microprocessor, and the gain adjustable amplifier is embodied by two cascaded feedback amplifiers that are connected between the vibration transducer and the microprocessor.

9. The knocking activated device according to claim 8, wherein the electromechanical device is part of a vehicle, and the microprocessor has an input connected to an ignition key of the vehicle for automatically generating the gain control signal when the ignition key is actuated.

10. The knocking activated device according to claim 1 , wherein the predetermined groups of knocks contain two series of predetermined groups of knocks, and wherein the comparing means uses one of the two series for a current comparison and the other series for a next comparison if result of the current comparison is positive.

11. A method for operating an electromechanical device responsive to a device control signal, comprising the steps of:

(a) storing data representative of predetermined groups of knocks through a user operable interface, each of the predetermined groups of knocks containing a predetermined maximum number of knocks;

12. The method for operating the electromechanical device according to claim 11, wherein, in step (c), the initial gain level is momentarily further decreased by steps up to a predetermined limit in response to successive gain control signals occurring within a predetermined period of time.

13. The method for operating the electromechanical device according to claim 11 , wherein step (b) comprises the step of filtering noises in the signal generated in step (b).

14. The method for operating the electromechanical device according to claim 11 , wherein the predetermined maximum number of knocks in step (a) is nine.

15. The method for operating the electromechanical device according to claim 11 , wherein the predetermined time period in step (d) is one second.

16. The method for operating the electromechanical device according to claim 11 , wherein step (e) further comprises the step of temporarily shutting down operation of the knocking activated device if the groups of knocks obtained from the discriminating means do not match the predetermined groups of knocks and if each of the groups of knocks obtained from the discriminating means contains a number of knocks that is equal to or lower than the maximum number of knocks.

17. The method for operating the electromechanical device according to claim 16, wherein the step of shutting down operation of the knocking activated device lasts about ten seconds.

18. The method for operating the electromechanical device according to claim 11 , wherein the electromechanical device is part of a vehicle having an ignition key, and step (e) further comprises the step of automatically generating the gain control signal when the ignition key of the vehicle is actuated.

19. The method for operating the electromechanical device according to claim 11, wherein the predetermined groups of knocks stored in step (a) contain two series of predetermined groups of knocks, and wherein step (e) comprises the step of using one of the two series for a current comparison and the other series for a next comparison if result of the current comparison is positive.

20. The method for operating the electromechanical device according to claim 11 , wherein steps (a), (b), (c), (d) and (e) are performed by a knocking activated device and wherein the electromechanical device is part of a vehicle, and the method further comprising steps of:

(i) depressing a programming button of the knocking activated device for a predetermined amount of time; and

(ii) depressing the programming button a multiple number of times in a predetermined period for storing or changing a data communication protocol.