Microphone disruption apparatus and method
An apparatus for use with an electronic device having a microphone. The apparatus comprises a structure configured to detachably couple to the device, and a generator supported by the structure. The generator is configured to generate a force that acts on the microphone and renders the microphone unresponsive to voice sounds.
1. An apparatus for use with an electronic device having a microphone, the apparatus comprising:
a structure configured to detachably couple to the device; and
a generator supported by the structure and fluidly coupled to the microphone, the generator configured to generate air pressure that acts on a diaphragm of the microphone and renders the microphone unresponsive to voice sounds.
2. The apparatus of claim 1 , wherein the air pressure generated by the generator causes clipping of the microphone.
3. The apparatus of claim 1 , wherein:
the diaphragm has an excursion limit; and
the air pressure generated by the generator causes the diaphragm to move to or near the excursion limit.
4. The apparatus of claim 1 , wherein the generator is configured to generate a varying air pressure wave.
5. The apparatus of claim 4 , wherein the generator is configured to receive a sine wave as a drive signal and generate the varying air pressure wave in response to the drive signal.
6. The apparatus of claim 4 , wherein the generator is configured to receive a voice signal, a structured noise signal or a music signal as a drive signal and generate the varying air pressure wave in response to the drive signal.
7. The apparatus of claim 1 , wherein the generator comprises a linear motor and a pressure cell.
8. The apparatus of claim 1 , wherein the generator comprises:
a spool having a bore;
an electromagnet coil wound around the spool;
a piston comprising a permanent magnet, the piston configured to move axially within the bore of the spool in response to a drive signal applied to the coil; and
a pressure cell comprising a compliant membrane and an outlet port, the membrane subject to displacement in response to forcible contact with the piston, thereby generating an air pressure wave.
9. The apparatus of claim 8 , wherein the piston comprises a first portion comprising the permanent magnet and a second portion comprising non-magnetic material.
10. The apparatus of claim 1 , further comprising a plenum supported by the structure and comprising an inlet port and an outlet port, the inlet port of the plenum configured to fluidly couple to the generator and the outlet port configured to fluidly couple to the microphone.
11. The apparatus of claim 1 , wherein the generator comprises a MEMS device, a vibrator, an electrostatic motor, a rotary motor, a vane pump, a ducted fan blower or a direct piston pump.
12. The apparatus of claim 1 , wherein the generator comprises a first end and a second end, and further comprises:
a first pressure cell adjacent the first end and configured to generate air pressure that acts on a diaphragm of a first microphone and renders the first microphone unresponsive to voice sounds; and
a second pressure cell adjacent the second end and configured to generate air pressure that acts on a diaphragm of a second microphone and renders the second microphone unresponsive to voice sounds.
13. The apparatus of claim 1 , further comprising:
a first auxiliary microphone supported by the structure and configured to receive voice sounds during a time in which the generator is active and the microphone of the device is rendered unresponsive to voice sounds.
14. The apparatus of claim 13 , further comprising vibration absorbing material disposed between the generator and one or both of the first auxiliary microphone and a portion of the structure to which the generator is mounted.
15. The apparatus of claim 13 , further comprising:
a second auxiliary microphone supported by the structure, the second auxiliary microphone responsive to mechanical noise resulting from operation of the generator and substantially unresponsive to the voice sounds received by the microphone of the electronic device;
wherein a signal produced by the second auxiliary microphone can be used to cancel the mechanical noise from a signal produced by the first auxiliary microphone.
16. The apparatus of claim 1 , wherein the structure comprises a cover or a sleeve configured to detachably couple to the device.
17. An apparatus for use with an electronic device having a microphone, the apparatus comprising:
a structure configured to detachably couple to the device; and
a generator supported by the structure, the generator configured to generate a force that acts on the microphone and renders the microphone unresponsive to voice sounds.
18. The apparatus of claim 17 , wherein the generator is configured to render unresponsive to voice sounds the microphone selected from the group consisting of a dynamic microphone, a condenser microphone, an electret microphone, a ribbon microphone, a piezoelectric microphone, a fiber optic microphone, and a MEMS microphone.
19. The apparatus of claim 17 , wherein the generator comprises a MEMS device, a vibrator, an electrostatic motor, a rotary motor, a vane pump, a ducted fan blower or a direct piston pump.
20. The apparatus of claim 17 , wherein the generator is configured to generator a pressure force, an electric force or a mechanical force.
21. A method involving a microphone of an electronic device, the method comprising:
generating, at a cover or a sleeve detachably coupled to an external surface of the device, a force that is directed at the microphone; and
rendering the microphone unresponsive to voice sounds by the force acting on the microphone.
22. The method of claim 21 , wherein the force is air pressure.
23. The method of claim 21 , wherein the force is mechanical vibration.
24. The method of claim 21 , wherein the force is an electric force.