Gas detector for mobile device including enclosure having interior chamber with audio loudspeaker, sealed loudspeaker opening, ventilation port, and gas sensor
A gas detection device includes an enclosure having an interior chamber, an audio loudspeaker in acoustic communication with the interior chamber of the enclosure, and a gas sensor configured to detect a gas within the interior chamber of the enclosure. The device may include a ventilation port configured to permit two-way gaseous communication between the interior chamber and an atmosphere external to the enclosure, where the atmosphere comprises the gas. The audio loudspeaker is configured to generate a pressure within the interior chamber. The pressure causes a portion of the external atmosphere to be drawn into the interior chamber via the ventilation port. The gas sensor may include an emitter and a receiver. The gas detection device can be integrated into a mobile electronic device, such as a smartphone or tablet computer.
1. A gas detection device comprising:
an enclosure having an interior chamber;
an audio loudspeaker in acoustic communication with the interior chamber of the enclosure;
a gas sensor configured to detect a gas within the interior chamber of the enclosure;
a ventilation port comprising a channel within the enclosure, the channel configured to permit two-way gaseous communication between the interior chamber and an atmosphere external to the enclosure, wherein the atmosphere comprises the gas; and
a loudspeaker opening in the enclosure, the loudspeaker opening being sealed to prevent ingress or egress of the gas into or out of the interior chamber via the loudspeaker opening,
wherein the channel has a length and a cross-sectional area, the length defined as a function of the cross-sectional area of the channel, a volume of the interior chamber which is 1000 cubic millimeters or less, and a Helmholtz resonance of the enclosure below a cut-off frequency at which the audio loudspeaker does not produce any audible noise.
2. The device of claim 1 , wherein the audio loudspeaker is configured to generate a pressure within the interior chamber, the pressure causing a portion of the atmosphere to be drawn into the interior chamber via the ventilation port.
3. The device of claim 1 , wherein the audio loudspeaker is configured to be driven below a cut-off frequency at which the audio loudspeaker does not produce any noise.
4. The device of claim 1 , wherein the audio loudspeaker is configured to be driven to output sound including at least one of music, audio portion of a video, human conversation being carried out using the device, and a computer-generated voice.
5. The device of claim 1 , wherein the gas sensor comprises an emitter and a receiver.
6. The device of claim 5 , wherein the emitter comprises a radiation source, and wherein the receiver comprises a radiation detector.
7. The device of claim 6 , further comprising a radiation filter disposed between the radiation source and the radiation detector.
8. The device of claim 5 , wherein the emitter and the receiver are disposed on or adjacent to opposing walls of the enclosure.
9. The device of claim 1 , wherein the gas sensor comprises a semiconductor material that changes in its electrical properties when exposed to a target gas.
10. The device of claim 1 , wherein the gas sensor comprises an electrode and porous membrane configuration.
11. A mobile electronic device comprising the device of claim 1 , wherein the mobile electronic device is one of a smartphone, a tablet computer, and a laptop computer.
12. The device of claim 1 , wherein the channel has a length and a cross-sectional area, the length defined as:
L
p
=
(
c
2
π
f
b
)
2
S
P
V
AB
-
1.463
S
P
π
where L p is the length of the channel, f b is the Helmholtz tuning frequency, V AB is a volume of the interior chamber, c is a constant value, and S P is the cross-sectional area of the channel.
13. A method for detecting a gas, the method comprising:
exposing a gas detection device to a target environment, the gas detection device comprising an enclosure having an interior chamber, an audio loudspeaker in acoustic communication with the interior chamber of the enclosure, a gas sensor configured to detect a gas within the interior chamber of the enclosure, a ventilation port comprising a channel within the enclosure, the channel configured to permit two-way gaseous communication between the interior chamber and an atmosphere external to the enclosure, wherein the atmosphere comprises the gas, and a loudspeaker opening in the enclosure, the loudspeaker opening being sealed to prevent ingress or egress of the gas into or out of the interior chamber via the loudspeaker opening, wherein the channel has a length and a cross-sectional area, the length defined as a function of the cross-sectional area of the channel, a volume of the interior chamber which is 1000 cubic millimeters or less, and a Helmholtz resonance of the enclosure below a cut-off frequency at which the audio loudspeaker does not produce any audible noise; and
causing the gas sensor to detect a gas within the interior chamber of the enclosure.
14. The method of claim 12 , wherein the method further comprises causing the audio loudspeaker to generate a pressure within the interior chamber, the pressure causing a portion of the atmosphere to be drawn into the interior chamber via the ventilation port.
15. The method of claim 12 , further comprising driving the audio loudspeaker below a cut-off frequency at which the audio loudspeaker does not produce any noise.
16. The method of claim 12 , wherein the interior chamber has a volume of approximately 1000 cubic millimeters or less.
17. The method of claim 12 , wherein the gas sensor comprises an emitter and a receiver.
18. The method of claim 17 , wherein the emitter comprises a radiation source, and wherein the receiver comprises a radiation detector.
19. A gas detection device comprising:
an enclosure having an interior chamber;
an audio loudspeaker in acoustic communication with the interior chamber of the enclosure;
means for detecting a gas within the interior chamber of the enclosure;
a ventilation port comprising a channel within the enclosure, the channel configured to permit two-way gaseous communication between the interior chamber and an atmosphere external to the enclosure, wherein the atmosphere comprises the gas; and
a loudspeaker opening in the enclosure, the loudspeaker opening being sealed to prevent ingress or egress of the gas into or out of the interior chamber via the loudspeaker opening,
wherein the channel has a length and a cross-sectional area, the length defined as a function of the cross-sectional area of the channel, a volume of the interior chamber which is 1000 cubic millimeters or less, and a Helmholtz resonance of the enclosure below a cut-off frequency at which the audio loudspeaker does not produce any audible noise.