Wearable device with air quality sensor
A wearable device with an air quality sensor, the wearable device, comprising a housing enclosing an electronic board, a display arrangement, a battery, the housing lodging a cavity with an internal area, the cavity containing an air quality sensor in the internal area, the cavity being delimited by a cavity wall and by a membrane, the membrane having an inner wall oriented toward the cavity internal area and an outer wall opposed to the inner wall, the internal area of the cavity being in fluid communication with the ambient air through the membrane, the membrane being permeable to air and substantially not permeable to water.
1. A wearable device with an air quality sensor, the wearable device comprising a housing enclosing an electronic board, a display arrangement,
the housing lodging a cavity with an internal area,
the cavity containing an air quality sensor in the internal area,
the cavity being delimited by a cavity wall and by a membrane,
the membrane having an inner wall oriented toward the cavity internal area and an outer wall opposed to the inner wall, the internal area of the cavity being in fluid communication with the ambient air through the membrane,
the membrane being permeable to air and substantially not permeable to water,
wherein the cavity wall is delimited by a top portion, a side portion and a bottom portion, the bottom portion of the cavity wall being entirely formed by the air quality sensor, and wherein an interface between the air quality sensor and the side portion is locally sealed, the cavity wall comprising on the side portion an opening closed off by the membrane.
2. The device according to claim 1 , wherein the housing is formed by a main casing, a top cover and a back plate,
the main casing comprising at least one through bore located in an opening area for fluid communication between the internal area of the housing and outside, the outer wall of the membrane facing the opening area.
3. The device according to claim 2 , wherein each through bores has typically a dimension comprised in the range 0.05 and 1.5 mm.
4. The device according to claim 1 , wherein the air quality sensor is able to determine at least one of a concentration of NO2 and O3.
5. The device according to claim 1 , wherein the air quality sensor is able to determine at least one of a concentration of NO2 and CO and SO2.
6. The device according to claim 1 , wherein the air quality sensor includes an amperometric sensor with a power consumption below 5 micro-amps.
7. The device according to claim 1 , wherein the air quality sensor includes an amperometric sensor with a volume less than 0.2 cc.
8. The device according to claim 1 , wherein the device is formed as a watch and wherein the cavity wall is delimited by a dial plate and by the air quality sensor, the dial plate defining the top portion and the side portion of the cavity wall.
9. The watch according to claim 8 , wherein the interface between the sensor and the dial plate is sealed using at least one gasket.
10. The watch according to claim 8 , wherein a shoulder is formed in the dial plate around the opening from a surface of the dial plate opposed to the cavity wall, the membrane being received against the shoulder.
11. The watch according to claim 10 wherein an inner space is located between the membrane and a perforated area, the inner space being insulated from the inside of the housing using a gasket inserted between the housing and the dial plate close to the opening.
12. The watch according to claim 1 , wherein the display arrangement comprises a plurality of physical stick-like hands forming analog indicators and at least a digital display area.
13. The device according to claim 1 wherein the electronic board comprises a hole, the size of the hole being adapted for inserting the air quality sensor through the hole, the sensor emerging from both sides of the electronic board.
14. The device according to claim 1 , wherein the display arrangement further comprises a multi-color indicator LED, whose color is controlled by the electronic board according to a sensed level of air pollutants in the sampled air.
15. The device according to claim 1 , further comprising a vibrator, controlled by the electronic board which is configured to activate the vibrator if a sensed level of pollutants exceeds a predefined threshold.
16. The device according to claim 1 , wherein the cavity is elsewhere isolated from the inside of the housing by using at least one gasket.
17. The device according to claim 1 wherein the internal area of the cavity is in fluid communication with the ambient air exclusively through the membrane, the cavity being elsewhere isolated from the inside of the housing.