WO2023039665A1

WO2023039665A1 - Mobile phone microphone jamming apparatus

Info

Publication number: WO2023039665A1
Application number: PCT/CA2022/051368
Authority: WO
Inventors: Evan MCDOUGALL; David NICKEL; Bruce CLELAND; Kevin Layden; Kerry Chin; Shawn Stevenson; Morgan GILBERT
Original assignee: Pozio Privacy Innovations Inc.
Priority date: 2021-09-15
Filing date: 2022-09-14
Publication date: 2023-03-23

Abstract

An apparatus for jamming at least one microphone of a mobile phone comprises a frame with a cavity that is configured to receive a mobile phone. A lower transducer assembly is mounted to a lower part of the frame and has a lower transducer emitting a lower sonic jamming signal and a lower sound chamber in sonic communication with the lower transducer and a reflecting surface which reflects the lower sonic jamming signal to a lower front part of the frame cavity. An upper transducer assembly is mounted at an upper part of the frame and has an upper transducer emitting an upper sonic jamming signal and an upper sound chamber in sonic communication with the upper transducer and a reflecting surface which reflects the upper sonic jamming signal to upper front part of the frame cavity. When the mobile phone is placed in the frame cavity at least one microphone of the mobile phone is located in the lower front part or upper front part of the frame cavity, such that one or more the lower and upper jamming signals jam the mobile phone microphone(s).

Description

MOBILE PHONE MICROPHONE JAMMING APPARATUS

TECHNICAL FIELD

[0001] The present disclosure is directed at a mobile phone microphone jamming apparatus.

BACKGROUND

[0002] Many electronic devices include a microphone for receiving input. For some such devices, the microphone may be always receiving sounds from the environment such that a processor within the electronic device may continuously scan for commands. Accordingly, this allows users to provide voice commands to the electronic devices at any time and receive a response or have the electronic device carry out an action.

[0003] More recently, the proliferation of mobile phones has taken advantage of such microphones to be always on and listening to the environment. The ability for mobile phones to recognize voice commands from an environment may provide various conveniences such as being able to activate a digital assistant or execute applications on the phone or control other devices. For example, mobile phones are generally connected to the Internet and mobile network and provide a great variety of capabilities for individual users and for the mobile communications industry at large, including the vendor of the mobile phone, the provider of the selected cloud services, the provider of the mobile application in use or installed, the provider of the Internet search services, and the provider of associated services related to intelligent assistants, which may or may not be voice activated. By continuously listening for voice commands, the mobile phone may recognize a command at any time using voice recognition software that is often executed in the cloud. In addition to recognizing commands, microphones may be used to record voices and speech to collect data which may be used to further train voice recognition engines to improve the accuracy of the voice recognition.

[0004] However, a user may not desire a mobile phone to be continuously listening for voice commands and instead may desire a convenient means for temporarily disabling or impeding this action. Furthermore, a user may not want third parties to collect the user’s personal information; since mobile phones often operate on voice recognition software that relies on machine learning, microphones may be used to collect speech and other sounds to further train the voice recognition engine. Although these activities may not be carried out, the hardware is capable of carrying out data collection for various purposes. In some cases, conversations and other sounds may be recorded and analyzed by a third party to generate data for marketing or other purposes. Since the hardware capability is available to direct recorded sounds to the cloud, the possibility for a malicious harvesting of information or spying also exists by unknown parties who may gain unauthorized access to the microphone on the electronic device.

SUMMARY

[0005] In accordance with one aspect of the invention there is provided an apparatus for jamming at least one microphone of a mobile phone, comprising a frame, a lower transducer assembly, and an upper transducer assembly. The frame has a cavity that is configured to receive a mobile phone. The lower transducer assembly is mounted at a lower part of the frame and has a lower transducer emitting a lower sonic jamming signal and a lower sound chamber in sonic communication with the lower transducer and having a reflecting surface which reflects the lower sonic jamming signal to a lower front part of the frame cavity. The upper transducer assembly is mounted at an upper part of the frame and has an upper transducer emitting an upper sonic jamming signal and an upper sound chamber in sonic communication with the upper transducer and having a reflecting surface which reflects the upper sonic jamming signal to upper front part of the frame cavity. When the mobile phone is placed in the frame cavity, at least one microphone of the mobile phone is located in the lower front part or upper front part of the frame cavity, such that the at least one microphone is jammed by one or both of the lower and upper sonic jamming signals. The lower transducer and upper transducer can each emit an ultrasonic jamming signal having a frequency of about 39.5 kHz.

[0006] A blower assembly can be mounted to the frame and have a blower that blows air towards a back part of the frame cavity; the blown air causes turbulence in and thereby jams a microphone on a mobile phone located in the back part of the frame cavity. A wireless charging pad for charging a mobile phone can be provided in the frame cavity. The wireless charging pad is in thermal communication with the blower assembly such that heat generated by the wireless charging pad is transferred to the air blown by the blower thereby cooling the wireless charging pad.

[0007] The frame can further comprise ribs spaced around an inner part of the frame; the spaces between ribs provide air flow channels to a mobile phone placed in the frame cavity. [0008] The apparatus can further comprise a microphone, a controller communicative with the microphone and a memory having encoded thereon an ambient audio level monitoring program that when executed by the controller measures ambient audio level with the microphone and reduces an energy output of one or more of the upper transducer, lower transducer and blower assembly when the measured ambient audio level falls below a selected threshold, and increases the energy output of one or more of the upper transducer, lower transducer and blower assembly when the measured ambient audio level exceeds the selected threshold.

[0009] The apparatus can further comprise an ambient light detector, a controller communicative with the ambient light detector in the frame cavity, and a memory having encoded thereon an ambient light level monitoring program that when executed by the controller measures ambient light level with the microphone and reduces an energy output of one or more of the upper transducer, lower transducer and blower assembly when the measured ambient light level falls below a selected threshold, and increases the energy output of one or more of the upper transducer, lower transducer and blower assembly when the measured ambient light levels exceeds the selected threshold. The ambient light level monitoring program can further comprise instructions that when executed by the controller determines a rate of ambient light level change measured by the ambient light detector, and only adjusts the energy output of the one or more of the upper transducer, lower transducer and blower assembly when the measured rate of ambient light level change exceeds a selected threshold.

[0010] Alternatively, the apparatus can further comprise an ambient light detector, a controller communicative with the ambient light detector in the frame cavity and the wireless charging pad, and a memory having encoded thereon an ambient light level monitoring program that when executed by the controller measures ambient light level with the microphone and the charging status of the wireless charging pad and reduces an energy output of one or more of the upper transducer, lower transducer and blower assembly when the measured ambient light level falls below a selected threshold and the wireless charging pad is not charging, and increases the energy output of one or more of the upper transducer, lower transducer and blower assembly when the measured ambient light levels exceeds the selected threshold and the wireless charging pad is charging.

[0011] The apparatus can further comprise a microphone, a controller communicative with the microphone and a memory having encoded with one more or models of voice commands and an operating system, that when executed by the controller determines whether a sound detected by the microphone is a voice command and when a voice command is detected, performs one or more operations of the apparatus. The microphone can be a located on the apparatus in a location other than the lower and upper front parts of the frame cavity such that the lower and upper sonic jamming signals do not interfere with the microphone.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Reference will now be made, by way of example only, to the accompanying drawings in which:

[0013] FIGS. 1A and 1 B are perspective views of an embodiment of a mobile phone microphone jamming apparatus for jamming one or more mobile phone microphones from monitoring sounds in an environment;

[0014] FIG. 2 is an exploded view of the mobile phone microphone jamming apparatus shown in FIG. 1 ;

[0015] FIGS. 3A and 3B are perspective views of upper and lower transducer assemblies of the mobile phone microphone jamming apparatus shown in FIG. 1 ;

[0016] FIG. 4 is a front view of a frame of the mobile phone microphone jamming apparatus shown in FIG. 1 containing the upper and lower transducer assemblies;

[0017] FIG. 5 is a block diagram of electronic components of the mobile phone microphone jamming apparatus according to an embodiment;

[0018] FIGS. 6A and 6B are graphs that illustrate the frequency responses of example high-pass filters that may comprise part of the mobile phone microphone jamming apparatus according to an embodiment;

[0019] FIG. 7 is a rear perspective view of a fan assembly of the mobile phone microphone jamming apparatus shown in FIG. 1 ; [0020] FIGS. 8A and 8B are front perspective views showing components of the mobile phone microphone jamming apparatus shown in FIG. 1 , wherein the frame and fan assembly are shown in FIG. 8A and the frame and a wireless charging pad are shown in FIG 8B;

DETAILED DESCRIPTION

[0021] A mobile phone typically has up to three areas where microphones reside: the lower front near the mouthpiece, the back near one or more cameras, and the upper front near an earpiece. Each of these microphones may be used when the phone is either actively recording (video or audio), or when the phone is idle but actively listening for an audio signal such as a voice command. Embodiments of the invention described herein relate generally to a mobile phone microphone jamming apparatus for jamming one or more microphones of a mobile phone, thereby preventing or impeding the mobile phone from recording a person’s voice or other ambient sounds. The mobile phone jamming apparatus is intended to increase privacy and peace of mind for a mobile phone user and anyone in the surrounding vicinity by preventing one or more microphones of a mobile phone placed in the vicinity of the apparatus from being able to listen to ambient sounds and to voice commands, thereby reducing or eliminating the chance of the mobile phone from triggering its voice assistant to respond to voice commands, to process and send information to associated cloud services, or to send audio recordings over the Internet for offline processing. A related benefit is that jamming the microphone(s) of the mobile phone prevents audio recordings on the device from being used for unwanted purposes.

[0022] Embodiments of the mobile phone microphone jamming apparatus generally comprise a frame with a cavity for receiving a mobile phone, a lower transducer assembly mounted at a lower part of the frame and an upper transducer assembly mounted at an upper side of the frame, wherein the lower and upper transducers are configured to emit respective lower and upper sonic jamming signals, for example, ultrasonic jamming signals. The lower and upper transducer assemblies are strategically placed on the frame to be in close proximity to expected locations of a mobile phone’s microphones when the mobile phone is placed on the cradle. The lower and upper transducer assemblies each have a transducer and a sound chamber in sonic communication with the transducer. Each sound chamber provides a specific and targeted means for directing and reflecting ultrasonic jamming signals from the associated transducer. Particularly, the lower sound chamber has a reflecting surface that reflects a lower jamming signal emitted by the lower transducer to a lower front part of the frame cavity, and the upper sound chamber has a reflecting surface that reflects an upper jamming signal emitted by the upper transducer to an upper front part of the frame cavity. A mobile phone mounted in the frame cavity is expected to have microphones in the upper and lower front parts of the frame cavity which are jammed by the upper and lower sonic jamming signals.

[0023] Each transducer is mounted in a resonance reducing material (silicone rubber) and the output of each transducer is directed laterally into the associated sound chamber. The sound chamber serves to direct and reflect the sound waves in a pattern that is approximately perpendicular to the angle of entry, but with a far wider dispersion angle than would be possible without any such sound chamber. This wider dispersion angle is required to “blanket” specific areas of the mobile device expected to contain one or more microphones with the jamming signal, thereby impeding or preventing the mobile device from using the microphone as a source input for speech recognition, audio recording or similar.

[0024] In some embodiments, the mobile phone microphone jamming apparatus further comprises a blower assembly that blows air towards one or more expected locations of the mobile phone’s microphones when placed on the cradle; in particular, the blower assembly can comprise a manifold that directs blown air upwards towards the back of the mobile phone where microphones are expected to be located near the cameras. The airflow presents turbulence to the microphones which deflects the microphone diaphragm and further disrupts the recording of intelligible speech. While a good majority of the intelligibility of voice and speech can be obscured with the use of two ultrasonic transducers and appropriate ultrasonic jamming signals, the effectiveness of jamming can be materially enhanced with the use of strategically directed air flow. Used in combination with ultrasonic signals, the airflow is expected to provide a mobile phone microphone jamming apparatus that is effective to jam the microphone(s) of mobile phones having varying sizes and positions on the apparatus.

[0025] In some embodiments, the mobile phone jamming apparatus comprises a wireless charger that is located in thermal proximity to the blower assembly such that heat generated when the wireless charger is operating is transferred to air blown by the blower assembly out of the mobile phone microphone jamming apparatus.

[0026] Referring to FIGS. 1A and 2 and according to one embodiment, a mobile phone microphone jamming apparatus 10 comprises a frame 12 having a front portion 12A and rear portion 12B that together define a generally rectangular shape with an interior cavity sized to receive a mobile phone as shown in dashed line in FIG. 1 B. An inner frame portion 12C comprises a series of spaced ribs 14 circumscribing the interior surface of the frame 12 wherein the spaces between ribs provide air channels for air to flow around and cool the mobile phone when mounted in the cavity, as well as serve as a grille for the transducers to emit their jamming signals. An ambient light detector 16 is provided in the interior cavity and a microphone 18 is provided at the top front of the frame 12 to detect ambient light levels and ambient audio levels respectively for use by the apparatus 10 to control jamming operation, as will be discussed in further detail below.

[0027] In some embodiments including the one shown in FIGS 1A-1 B, a wireless charging pad 20 is provided inside the frame’s interior cavity; the frame 12 and charging pad 20 are tilted at an acute angle from vertical so that the mobile phone will stably rest on the charging pad 20 within the frame’s cavity. The wireless charging pad 20 uses conventional wireless charging technology such as the Qi inducting charging standard and thus will not be described in detail here.

[0028] Referring to FIGS. 2, 3A, and 3B, the mobile phone microphone jamming apparatus 10 further comprises a pair of transducer assemblies, namely a lower transducer assembly 22 mounted in the bottom of the frame 12 facing generally upwards and an upper transducer assembly 24 mounted on the upper side of the frame facing generally inwards into the frame cavity. The lower transducer assembly 22 comprises a lower transducer 25 and a lower sound chamber 26 and the upper transducer assembly 24 comprises an upper ultrasonic transducer 27 and an upper sound chamber 28 respectively. The lower and upper sound chambers 26, 28 each comprise a receptacle for receiving their respective transducers 25, 27 and a sonic reflecting surface that shapes and reflects ultrasonic signals emitted by the transducers 25, 27 outward. The lower and upper sound chambers 26, 28 can further comprise a transducer dampener contacting the respective transducers 25, 27 and which serves as a resonance reducing material; the transducer dampener can be made of a suitable sound dampening material such as silicone rubber.

[0029] Referring to FIG. 4, the lower transducer assembly 22 is mounted on the inner frame portion 12C with the sound chamber 26 positioned to reflect the ultrasonic signals generally upwardly past the ribs 14 and into a lower front part of the frame cavity, i.e. perpendicularly to the angle of entry of the transducer 25 and with a dispersion angle selected to blanket the lower face of the mobile phone placed in the frame cavity, where a microphone near the mouthpiece of a mobile phone is expected. Similarly, the upper transducer assembly 24 is mounted on the inner frame portion 12C with the sound chamber 28 positioned to reflect the ultrasonic signals generally laterally inwards past the ribs 14 into an upper front part of the frame cavity, i.e. perpendicularly to the angle of entry of the transducer 27 and with a dispersion angle selected to blanket the top face of the mobile phone when placed in the frame cavity, where a microphone near the mobile phone earpiece is expected. The general direction of the ultrasonic signals can affect the degree of success and of jamming the mobile phone microphone(s), and in particular, the upper sound chamber 28 can be configured and positioned to cause the ultrasonic jamming signal to cause a “glancing blow” to the front microphones.

[0030] Referring to FIG. 5, the transducers 25, 27 are configured to emit a jamming signal. It is to be appreciated that the transducers are not particularly limited and may be a device capable of emitting a signal to jam a microphone. In particular, the transducers emit sound waves that may reach a microphone of an external electronic device. The jamming signal may have a frequency of about 39.5 kHz, which is typically beyond the audible range of the human ear. The transducers 25, 27 can be for example a commercially available ultrasonic sensor configured to emit a 39.5 kHz ultrasonic signal. Accordingly, the transducers may be operated in a room without any significantly noticeable sound to human occupants in the room.

[0031] The manner by which the transducers jam the microphone of a mobile phone is not particularly limited. In the present example, the transducers may generate a waveform based on an electrical signal received from a controller 30. The waveform is not limited and may be custom designed for a microphone of specific external electronic device. It is to be appreciated by a person of skill that different microphones on different external electronic devices may respond to jamming signals with different waveforms. Accordingly, the transducers 25, 27 may be configured to generate sound signals having different waveforms for different mobile phones to be jammed. The signal generated by the transducers 25, 27 may be amplified using an amplifier to increase the efficiency of the jamming. In the present example, a high-end, consumer hi-fi home theater amplifier that is able to amplify signals up to about 100 kHz is used, but in other examples, amplifiers may be configured to amplify smaller ranges of frequencies. For example, as in the embodiments discussed herein, an integrated circuit may be used instead of a consumer amplifier. [0032] An example of a signal that may be used to jam a microphone is a combination of a tone at about 39.5 kHz mixed with shaped (filtered), band limited noise The jamming signal may have a frequency of about 39.5 kHz, which is typically beyond the audible range of the human ear. The tone may be generated using a 384 element lookup table having one cycle of a sine wave for efficiency and to reduce the computational resources used to generate the tone. The signal is then generated by filtering a sequence of samples generated using a random number function. Before filtering, the sample values may be distributed with approximately a uniform distribution between the values -32768 and 32767. A high-pass filter may be used to reduce the power of the signal in lower frequencies. The high-pass filter may have a finite impulse response with coefficients h = [0.5, -0.5],

[0033] Referring to FIG. 6A, the frequency response of the filter of the present example is shown. It is to be appreciated by a person of skill with the benefit of this description that the use of the high-pass filter decreases the volume of audible sounds from the transducers. In different embodiments, the filter may have different characteristics. For example, in different embodiments the filter may have the frequency response as depicted in FIG. 6B, which is discussed further below in respect of the embodiments described herein. After filtering the signal may be amplified to about 3.4 V_rms at the input to the transducers.

[0034] Referring again to FIG. 5, a microphone 18 can be provided to monitor an environment for a voice command. The manner by which the microphone 18 monitors for a voice command is not limited and may involve an application or running on the controller 30 to detect known commands. It is to be appreciated by a person of skill that since the apparatus 10 may not have any connection to a network, the controller 30 is to carry out all voice recognition functionality locally to detect and process a voice command.

[0035] In operation, the microphone 18 operates as another transducer to convert the sound waves into a digital signal for the controller 30 to process. The controller 30 may include a voice recognition engine or a natural language processing engine to detect the voice command locally and to carry out a predetermined action. For example, the voice command may be to deactivate the transducers 25, 27 which stops the transducers 25, 27 from emitting the jamming signal. In other examples, the voice command may activate the transducers or carry out other functionality. [0036] Since the transducers 25, 27 emit a jamming signal, the microphone 18 may also be jammed in some examples. To reduce the likelihood of jamming the microphone 18, the microphone 18 is placed at a location away from the signal path of the transducers 25, 27 e.g. at the top front of the frame 12. In other examples, the microphone 18 may be configured to be nonresponsive to frequencies at which the transducers 25, 27 emits sounds. In another example, the microphone 18 may include filters to block the jamming signal from the transducers.

[0037] Optionally, a memory storage unit 34 can be provided to store one or more models of the voice commands in a record. In examples where the apparatus 10 is to accept multiple voice commands with different functionality, the voice command models may be stored in a database having a plurality of records. The manner by which the memory storage unit 34 stores the records is not particularly limited. Each record may include a voice command model, such as a model of a wake command, and the associated function, such as deactivating the transducers 25, 27. Multiple models of voice commands may be stored in the memory storage unit 34 without using a database in at least some other embodiments. The memory storage unit 34 comprises a flash memory and RAM. The flash memory has encoded thereon computer program code that is executable by the processor and that, when executed by the processor, causes the processor to perform the methods described herein, including jamming signal generation and audio detection. An example processor is the ARM Cortex-M7^TM processor.

[0038] Furthermore, the memory storage unit 34 may be a non-transitory machine- readable storage medium such as an electronic, magnetic, optical, or other physical storage device. In the present example, the memory storage unit 34 is a persistent memory. In at least some embodiments, the memory storage unit 34 may also store an operating system that is executable by the controller 30 to provide general functionality to the apparatus 10. For example, the operating system may provide various operations on the apparatus 10 such as monitoring for a voice command, such as a wake word. Examples of operating systems include WINDOWS, MACOS, iOS, ANDROID, LINUX, and UNIX. The memory storage unit 34 may additionally store instructions to operate at the driver level to communicate with other components and peripheral devices of the apparatus 10 such as various LEDS, display screens, touchscreens or sensors (not shown).

[0039] The controller 30 is configured to control the transducers 25, 27 in response to input received at the microphone 18. In particular, the controller 30 may configured to toggle the transducers 25, 27 between an active state and an inactive state. In the active state, the transducers 25, 27 emit the jamming signal as described above. In the present example, the controller 30 may send electrical signals directly to the transducers 25, 27, such as generated waveforms to cause the transducers 25, 27 to emit the jamming signal. In other examples, a separate microcontroller with relatively lower processing power may be used such that the controller 30 may send a control signal to cause the separate microcontroller to operate the transducers 25, 27.

[0040] The manner by which the controller 30 operates the transducers 25, 27 is not limited and may be varied depending on user preferences. For example, the controller 30 may continuously send the jamming signal to be emitted to maintain the transducers 25, 27 in the active state. Upon receiving a voice command to toggle the transducers 25, 27 to the inactive state, the controller 30 may automatically re-activate the transducers 25, 27 after a period of time. The period of time is not limited and may be after 10 seconds, 20 seconds, or longer. The period of time may be shorter than 10 seconds as well. In other examples, the controller 30 may monitor via the microphone 18 for further sounds or voice commands intended for the microphone of the mobile phone and re-activate the transducers 25, 27 after no further sounds or voice commands are detected. In further examples, the controller 30 may monitor for a re-activate command instead of automatically re-activating the transducers 25, 27 such that the transducers 25, 27 remains locked in a state until user input is received.

[0041] As discussed above, the ultrasonic jamming performed by the apparatus 10 is performed on one or more microphones of the mobile phone. The microphone output of the mobile phone can be modeled as an amplified input signal plus a non-linear component:

Y = Ax + Bx² (1) where Y is the output electrical signal, x is the input acoustic signal, and A and B are gain factors.

[0042] If the input is comprised of two tones, then the non-linear term produces tone signals that are related to the sum and difference of the two tone frequencies. Assuming two ultrasonic frequencies fi and f2 that are not audible to humans, the output of Equation (1) has the following form:

[0043] The linear term consists of two ultrasonic tones that are not audible. The non-linear term can be further expanded to the following, where N is the non-linear portion of the output:

[0044] The first two terms are periodic signals in the ultrasonic frequency range with frequencies fi and f2. The third term of N can be evaluated as a combination of single tones, using the trigonometric identity:

[0045] Then the final form for N is:

[0046] The tone with frequency fi + f2 is yet another inaudible ultrasonic tone. But the tone with frequency fi - f2 can be made to fall into the audible frequency range for appropriate values of fi and f2 The second tone accordingly acts as a frequency translator that shifts the signal down by f2 Hz. For example, in at least some embodiments ultrasonic tones at 41 kHz and 40 kHz are applied to the input of the mobile phone’s microphone(s), thereby causing the microphone output to have a signal component at 1 kHz. Consequently, even though there is no audible sound provided to the input of the mobile phone’s microphone(s), the output of the microphone(s) contain an audible signal.

[0047] In a similar manner, in at least some embodiments one of the tones is replaced with a more complex signal, such as random noise, whether in digital or analog form. Applying this principle, in at least some embodiments jamming is performed using a combination of a tone at 39.5 kHz added to a bandlimited noise signal, such as a signal bandlimited to 33-48 kHz. In this case, the output of the mobile phone’s microphone(s) has a 0 to 8.5 kHz noise component. The bandlimited noise signal may be, for example, a bandlimited white noise signal (i.e. , a signal where the different frequency components have, on average over a long enough period of time, the same power). Alternatively, the bandlimited noise signal may be, for example, a bandlimited Gaussian noise signal (i.e., a signal where the different frequency components follow a Gaussian distribution). In at least some embodiments, the more complex signal used to replace the second tone may be time-varying over a certain duration instead of a constant over that duration as the tones are; for example, all or portions of the bandlimited noise signal may vary in amplitude over time and/or in response to an input such as ambient noise. While the above example refers to a tone at 39.5 kHz used in conjunction with a bandlimited noise signal spanning 33-48 kHz, different frequencies for the tone and bandlimited signal may be used. For example, in at least some example embodiments the tone may be any signal that falls within the frequency range of the bandlimited signal.

[0048] In embodiments that use a noise signal, there are several factors that affect the shape of the noise signal seen by the external electronic device 100:

1 . When outputting the signal to the ultrasonic transducers 25, 27, the reconstruction filter in the DAC (digital to analog converter) in the controller 30 may have an effect. If the jamming signal is produced in a digital system with a 96 kHz sample rate, at least some embodiments comprise a low-pass filter in the DAC that attenuates signals above 48 kHz. In practice, frequencies close to 48 kHz, but lower than 48 kHz, are attenuated.

2. In at least some embodiments the transducers 25, 27 have a frequency response that is limited to a narrow band of frequencies, with a peak at the resonant frequency (e.g., 40 kHz). Even if the electrically generated noise signal has a flat frequency response in a particular range, the acoustic signal produced accordingly has a peak at the transducers’ resonant frequency.

[0049] In at least some example embodiments, the transducers 25, 27 have a resonance frequency of 40 kHz, fi is equal to 40 kHz, and f2 is equal to 39.5 kHz; the resonant peak of the noise acoustic signal is accordingly translated to 500 Hz, which in the audible frequency band of the mobile phone’s input. This helps facilitate that the most powerful frequency range of the apparatus 10 is in the frequency range where speech is typically most powerful. The processor generates the 39.5 kHz tone using a 192 element lookup table stored in the flash memory containing one cycle of a sine wave for efficiency.

[0050] In at least some other example embodiments that that use the bandlimited noise signal instead of a single tone at f₂, the processor generates the bandlimited noise signal by filtering a sequence of samples generated using a random number function. Before filtering, the sample values are distributed with an approximately uniform distribution between the values - 32768 and 32767. A high-pass filter having characteristics such as those depicted in FIG. 6B is used to reduce the power of the signal in lower frequencies. The high-pass filter in at least some embodiments is an FIR filter with coefficients h = [0.029205 -0.237488 0.466583 -0.237488 0.029205], Using the high-pass filter lowers the volume of audible sounds from the transducers 25, 27.

[0051] Each transducer 25, 27 may or may not receive an amplified signal that is an exact replica of that which is received by the other transducers 25, 27 in the apparatus 10. In this manner, the variance in signal composition and frequency content may make the microphone jamming more effective because the mobile phone is receiving signals that differ and vary over time. If the two signals are uncorrelated, then any type of noise reduction performed by the mobile phone will be less effective.

[0052] Each transducer 25, 27 may or may not have amplification levels that are controlled by the controller 30 so as to further differentiate the jamming signal and de-correlate the jamming signal from other jamming signals that are also in the apparatus 10, serving to confuse or negatively affect the mobile phone’s microphone(s) and the phone’s ability to record or sample audio and speech.

[0053] The jamming signal involves the use of a pseudo-noise sequence generated by a linear congruential generator (LOG). An LCG produces a sequence of numbers that repeats over a fixed period. A well designed LCG will generate pseudo-noise with a uniform distribution of amplitudes and will have a long period for the pattern of symbols that it produces. A series of audio samples produced by the output of an LCG will sound like noise. Producing two uncorrelated pseudo-noise sequences can be done by: running two LCGs with the same sequence but at different starting points; and running two LCGs with different sequences.

[0054] Referring now to FIGS. 2, 7, and 8A, the mobile phone microphone jamming apparatus 10 further comprises a blower assembly 36 that is operable to direct an airflow upwards and across the back of a mobile phone mounted on the apparatus, to jam any microphone located on the back of the mobile phone. The blower assembly 36 comprises a rear shell 38 housing: a PCB assembly 40, a blower fan 42 and fan gasket 43, an air manifold 44 and a speaker 46. The blower fan 40 can be a conventional DC blower fan consisting of an impeller, shaft or bearings, and a motor. The fan gasket 43 and blower fan 42 are affixed to rear shell 38 with the blower fan outlet facing upwards. The manifold 44 is affixed to the rear shell 38 with an inlet in communication with the blower fan outlet and an outlet facing upwards through a vent opening in the rear shell. The speaker 46 and mounted to the rear shell 38. The PCB assembly 40 is mounted to the rear shell 38 over the blower fan 42 and air manifold 44 and is electronically connected to the speaker 46 and blower fan 42 to provide power to and control operation of these components. The rear shell 38 is then mounted to a frame mounting plate 12D on the rear portion 12B of frame 12, such that the rear shell 38 with the air blower assembly 36 protrudes from the back of the frame 12.

[0055] Referring now to FIGS. 2, 8A and 8B, the charging pad 20 is mounted to the front of the frame mounting plate 12D and extends forwards through the frame cavity. A mobile phone mounted on the apparatus 12 will have its back resting on the charging pad 20; as noted above the charging pad 20 provides wireless inductive charging to mobiles phones having this capability. As can be seen in FIG. 8A, the frame mounting plate 12D is provided with openings 48 to provide airflow communication between the blower assembly 36 and the charging pad 20, such that air blown by the blower assembly 20 is used to remove heat generated by the charging pad 20 during a charging operation through the vent in the rear shell 38.

[0056] The PCB assembly 40 comprises the controller 30 which is further programmed to monitor the speed and current draw of the blower fan 42 and vary the fan speed (and thus, airflow speed) to suit the microphone jamming and charging pad cooling requirements. In operation, the blower assembly 36 blows air through the air manifold 44 and out of the rear shell 38 in a generally upwards direction. The airflow draws heat away from the charging pad 20 as well as presents turbulence to the microphones on the back of the mobile phone, which deflects the microphone diaphragm and thereby disrupting the recording of intelligible speech. The air flow is used in combination with ultrasonic jamming signals from the transducers 25, 27, to provide more effective microphone jamming operation than with just ultrasonic jamming signals.

[0057] Referring to FIGS. 1 and 5 and according to some embodiments, the controller 30 is further programmed with an ambient audio level monitoring module, and/or an ambient light monitoring module.

[0058] When the ambient audio level module is executed by the controller 30, the microphone 18 is used to measure ambient audio levels to infer human activity levels. For example, at night time when persons are asleep there may not be a need for microphone jamming and the controller 30 can be programmed to reduce the strength of the ultrasonic jamming signals. Additionally, the controller 30 can be programmed to reduce the operation of the blower assembly to reduce air flow noise. When the ambient noise increases, it is inferred that human activity has increased requiring a greater chance of the need for jamming; the controller 30 can be programmed to increase the strength of the ultrasonic jamming signals and air flow accordingly.

[0059] The controller 30 measures the audio activity level by estimating the power level of the signal entering the microphone 18. One way to estimate power level is to calculate the RMS (root mean square) value of the digital samples over a fixed interval. In statistical terms this can be considered the standard deviation of the sample values over a fixed interval. Measuring the variance is effectively the same thing. Since audio signals are zero mean, the variance is the sum of the squares of the input audio samples. A peak power detector can be implemented by filtering the power estimates, with a filter that rises quickly and decays slowly. Once the peak power is detected, the controller 30 sets a hangover counter that counts down over a long period, for example 300 seconds. Once the peak power exceeds a set threshold, a “speech active” state is entered immediately, but is not exited for at least 300 seconds. The controller 30 then resets the hangover counter to 300 every time a peak power over the threshold is detected. Once speech is detected, the light sensor 16 can be used to determine if a phone is sitting in the invention. If it is, then the more aggressive jamming is applied, until the hangover counter expires.

[0060] When the ambient light monitoring module is executed, the ambient light detector 16 is used to detect ambient light in order to infer the presence of a mobile device being placed in the designated location. The ambient light detector 16 is mounted on the wireless charging pad 20 and when it detects light, and the wireless charging pad 20 is not charging, the controller 30 concludes there is no mobile phone present and instructs the transducers 26, 27 to reduce the ultrasonic jamming signal to lower energy output and the blower assembly 36 to reduce air flow to reduce noise. When the ambient light detector 16 does not detect light and the wireless charging pad 20 detects a mobile phone and is charging, the controller 30 can be programmed to increase the strength of the ultrasonic jamming signals and air flow accordingly. In some embodiments, the apparatus 10 may not feature a wireless charging pad, in which case the apparatus 10 relies solely on the ambient light detector 16 to detect the presence of a mobile phone. In some embodiments, the ambient light monitoring module is further programmed with instructions to determine the rate of light change detected by the ambient light detector 16, wherein a rapid change from light detected to no light detected indicates a mobile phone has been placed on the apparatus 10 and vice versa indicates that a mobile phone has been removed from the apparatus 10; in contrast, a slower changer of detected light change indicates that environmental conditions has caused the light change (e.g. sunset I sunrise, drapes closing I opening) instead of the placement or removal of a mobile phone.

[0061] The mobile phone microphone jamming apparatus 10 may include additional components (not shown) such as various input and output devices to interact with a user to control the apparatus 10. It is to be appreciated by a person of skill with the benefit of this description that the apparatus 10 may typically exclude other interfaces that provide for connectivity. Accordingly, the apparatus 10 may be completely disconnected from other networks such that it cannot be remotely controlled or hacked by an external party via the internet. In the present example, the apparatus 10 includes a transducers, a microphone 18, a memory storage unit 34, and a controller 30.

[0062] It is to be appreciated by a person of skill with the benefit of this description that variations to the apparatus 10 are contemplated. For example, although the described embodiment discloses using two transducers 25, 27, it is to be understood that one transducer or more than two transducers may be used.

[0063] As another example of a variation, the apparatus 10 may include a manual input device to receive user input and to interact with a user of the apparatus 10. The manual input device is not particularly limited and may be used to control various features of the apparatus 10, such as locking the transducers in one state or the other, adjusting the volume of the transducers, adjusting the sensitivity of the microphone 18, as well as other features. The form of the manual input device is not limited and may be a touchscreen in some examples, or may be one or more actuating buttons.

[0064] Furthermore, the apparatus 10 can include an embedded voice processing component that enables voice or wake-word detection. In essence, the microphone 18 can be utilized to listen for a command (spoken) word in order to temporarily pause its jamming function, thereby enabling the user to access normal mobile phone features for a time-limited period, at which point the invention would automatically revert to jamming.

[0065] The embodiments have been described above with reference to flow, sequence, and block diagrams of methods, apparatuses, systems, and computer program products. In this regard, the depicted flow, sequence, and block diagrams illustrate the architecture, functionality, and operation of implementations of various embodiments. For instance, each block of the flow and block diagrams and operation in the sequence diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified action(s). In some alternative embodiments, the action(s) noted in that block or operation may occur out of the order noted in those figures. For example, two blocks or operations shown in succession may, in some embodiments, be executed substantially concurrently, or the blocks or operations may sometimes be executed in the reverse order, depending upon the functionality involved. Some specific examples of the foregoing have been noted above but those noted examples are not necessarily the only examples. Each block of the flow and block diagrams and operation of the sequence diagrams, and combinations of those blocks and operations, may be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

[0066] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. Accordingly, as used herein, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and “comprising”, when used in this specification, specify the presence of one or more stated features, integers, steps, operations, elements, and components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and groups. Directional terms such as “top”, “bottom”, “upwards”, “downwards”, “vertically”, and “laterally” are used in the following description for the purpose of providing relative reference only, and are not intended to suggest any limitations on how any article is to be positioned during use, or to be mounted in an assembly or relative to an environment. Additionally, the term “connect” and variants of it such as “connected”, “connects”, and “connecting” as used in this description are intended to include indirect and direct connections unless otherwise indicated. For example, if a first device is connected to a second device, that coupling may be through a direct connection or through an indirect connection via other devices and connections. Similarly, if the first device is communicatively connected to the second device, communication may be through a direct connection or through an indirect connection via other devices and connections. The term “and/or” as used herein in conjunction with a list means any one or more items from that list. For example, “A, B, and/or C” means “any one or more of A, B, and C”. A reference to a quantity being “about” or “approximately” a certain value means, unless otherwise indicated, that quantity being within +/- 10% of that value. [0067] It should be recognized that features and aspects of the various examples provided above may be combined into further examples that also fall within the scope of the present disclosure.

Claims

CLAIMS What is claimed is:

1 . An apparatus for jamming at least one microphone of a mobile phone, comprising:

(a) a frame having a cavity and configured to receive a mobile phone in the cavity;

(b) a lower transducer assembly mounted at a lower part of the frame and having a lower transducer emitting a lower sonic jamming signal and a lower sound chamber in sonic communication with the lower transducer and having a reflecting surface which reflects the lower sonic jamming signal to a lower front part of the frame cavity; and

(c) an upper transducer assembly mounted at an upper part of the frame and having an upper transducer emitting an upper sonic jamming signal and an upper sound chamber in sonic communication with the upper transducer and having a reflecting surface which reflects the upper sonic jamming signal to upper front part of the frame cavity; wherein when the mobile phone is placed in the frame cavity at least one microphone of the mobile phone is located in the lower front part or upper front part of the frame cavity.

2. The apparatus as claimed in claim 1 further comprising a blower assembly mounted to the frame and having a blower that blows air towards a back part of the frame cavity, for causing turbulence in and thereby jamming a microphone on a mobile phone located in the back part of the frame cavity.

3. The apparatus as claimed in claim 2 further comprising a wireless charging pad for charging a mobile phone in the frame cavity, the wireless charging pad in thermal communication with the blower assembly such that heat generated by the wireless charging pad is transferred to the air blown by the blower thereby cooling the wireless charging pad.

4. The apparatus claimed in claim 1 wherein the frame further comprise ribs spaced around an inner part of the frame, the spaces between ribs providing air flow channels to a mobile phone placed in the frame cavity.

5. The apparatus as claimed in claim 1 wherein the lower transducer and upper transducer emit an ultrasonic jamming signal having a frequency of about 39.5 kHz.

6. The apparatus as claimed in claim 2 further comprising a microphone, a controller communicative with the microphone, and a memory having encoded thereon an ambient audio level monitoring program that when executed by the controller measures ambient audio level with the microphone and reduces an energy output of one or more of the upper transducer, lower transducer and blower assembly when the measured ambient audio level falls below a selected threshold, and increases the energy output of one or more of the upper transducer, lower transducer and blower assembly when the measured ambient audio level exceeds the selected threshold.

7. The apparatus as claimed in claim 2 further comprising an ambient light detector, a controller communicative with the ambient light detector in the frame cavity, a memory having encoded thereon an ambient light level monitoring program that when executed by the controller measures ambient light level with the microphone and reduces an energy output of one or more of the upper transducer, lower transducer and blower assembly when the measured ambient light level falls below a selected threshold, and increases the energy output of one or more of the upper transducer, lower transducer and blower assembly when the measured ambient light levels exceeds the selected threshold.

8. The apparatus as claimed in claim 3 further comprising an ambient light detector, a controller communicative with the ambient light detector in the frame cavity and the wireless charging pad, and a memory having encoded thereon an ambient light level monitoring program that when executed by the controller measures ambient light level with the microphone and the charging status of the wireless charging pad and reduces an energy output of one or more of the upper transducer, lower transducer and blower assembly when the measured ambient light level falls below a selected threshold and the wireless charging pad is not charging, and increases the energy output of one or more of the upper transducer, lower transducer and blower assembly when the measured ambient light levels exceeds the selected threshold and the wireless charging pad is charging.

9. The apparatus as claimed in claims 7 or 8, wherein the ambient light level monitoring program comprises instructions that when executed by the controller determines a rate of ambient light level change measured by the ambient light detector, and only adjusts the energy output of the one or more of the upper transducer, lower transducer and blower assembly when the measured rate of ambient light level change exceeds a selected threshold.

10. The apparatus as claimed in claim 2 further comprising a microphone, a controller communicative with the microphone, and a memory having encoded thereon one more or models of voice commands and an operating system, that when executed by the controller determines whether a sound detected by the microphone is a voice command and when a voice command is detected, performs one or more operations of the apparatus.

11. The apparatus as claimed in claim 10 wherein the microphone at a located on the apparatus at a location other than the lower and upper front parts of the frame cavity such that the lower and upper sonic jamming signals do not interfere with the microphone.