Sintered filter material and grill design to reduce and mitigate wind noise for perception
A sensor module comprising a housing defining an internal cavity having a proximal opening and a distal opening, a first barrier that covers the proximal opening of the internal cavity, a second barrier that is positioned between the first barrier and the proximal opening of the internal cavity, at least one microphone acoustically coupled to the distal opening of the internal cavity, and a porous plastic material that fills a particular portion of the internal cavity located between the proximal opening and the distal opening.
1. A sensor module comprising:
a housing defining an internal cavity, wherein the internal cavity has a proximal opening and a distal opening;
a first barrier, wherein the first barrier covers the proximal opening of the internal cavity;
a second barrier, wherein the second barrier is positioned between the first barrier and the proximal opening of the internal cavity;
at least one microphone acoustically coupled to the distal opening of the internal cavity; and
a porous plastic material that fills a particular portion of the internal cavity, wherein the particular portion is located between the proximal opening and the distal opening.
2. The sensor module of claim 1 , wherein the porous plastic material comprises at least one of polyethylene, polypropylene, polyvinylidene fluoride, or polytetrafluoroethylene.
3. The sensor module of claim 1 , wherein the porous plastic material has a pore size between 10 microns and 50 microns.
4. The sensor module of claim 1 , wherein the porous plastic material has a pore volume between 20% and 65%.
5. The sensor module of claim 1 , wherein the porous plastic material is attached to an interior surface of the internal cavity by an adhesive material.
6. The sensor module of claim 1 , wherein the internal cavity has a tapered shape such that a cross-sectional area of the internal cavity decreases with increasing distance from the proximal opening.
7. The sensor module of claim 6 , wherein the porous plastic material completely fills the cross-sectional area of the internal cavity in the particular portion of the internal cavity.
8. The sensor module of claim 1 , wherein the first barrier comprises a perforated plate.
9. The sensor module of claim 8 , wherein the perforated plate has a plurality of perforations, each perforation having a diameter between 0.5 and 1 millimeters.
10. The sensor module of claim 9 , wherein perforated plate has a thickness between 1 and 2 millimeters.
11. The sensor module of claim 8 , wherein the perforated plate has a perforation ratio of between 30% and 50%.
12. The sensor module of claim 1 , wherein the second barrier comprises an acoustic mesh.
13. The sensor module of claim 1 , wherein the acoustic mesh comprises polyester monofilaments that define pores, wherein the pores have a size between 10 and 15 microns.
14. The sensor module of claim 1 , wherein the second barrier is attached to the first barrier.
15. The sensor module of claim 1 , wherein the porous plastic material is spaced apart from the second barrier.
16. The sensor module of claim 1 , further comprising a third barrier positioned between the at least one microphone and the distal opening of the internal cavity, wherein the third barrier comprises a water impermeable membrane.
17. A vehicle comprising:
a microphone module including:
a housing defining an internal cavity, wherein the internal cavity has a proximal opening and a distal opening;
a first barrier, wherein the first barrier covers the proximal opening of the internal cavity;
a second barrier, wherein the second barrier is positioned between the first barrier and the proximal opening of the internal cavity;
at least one microphone acoustically coupled to the distal opening of the internal cavity; and
a porous plastic material that fills a particular portion of the internal cavity, wherein the particular portion is located between the proximal opening and the distal opening; and
a control system communicably coupled to the microphone module to receive audio data from the at least one microphone.
18. The vehicle of claim 17 , wherein the porous plastic material has a pore size between 10 microns and 50 microns.
19. The vehicle of claim 17 , wherein the first barrier comprises a perforated plate, wherein the second barrier comprises an acoustic mesh.
20. The vehicle of claim 17 , wherein the control system is configured to control operation of the vehicle based on the audio data.