Sensor node

• US 20070030154A1
• Filed: 08/23/2005
• Published: 02/08/2007
• Est. Priority Date: 04/08/2005
• Status: Active Grant

• Current Assignee: Maxell, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Shimura, Takanori, Kuriyama, Hiroyuki, Aiki, Kiyoshi, Yamashita, Shunjo
• Granted Patent: US 7,626,498 B2
• Time in Patent Office: Days
• US Class Current: 340/572.700
• CPC Class Codes: H01Q 1/273 Adaptation for carrying or wearing by persons or animals
• CPC Class Codes: H01Q 9/0485 Dielectric resonator antennas

Abstract

To secure a stable radio-communication performance in a sensor node, the sensor node with a radio-communication circuit and a sensor, for transmitting data measured by the sensor through radio-communication, includes a first board BO2 on which an antenna ANT1 connected to the radio-communication circuit is placed, a case CASE1 containing the first board BO2, and a band that is attached to the case CASE1 so as to fix the case CASE1 to the skin. The antenna ANT1 is placed in an upper portion of the case CASE1, which corresponds to a 12 o'"'"'clock direction of a wristwatch.

Claims

1. A sensor node having a radio-communication circuit and a sensor, for transmitting data measured by the sensor by radio communication, comprising:

a first board on which an antenna connected to the radio-communication circuit is placed;

a battery for supplying a power to the radio-communication circuit and the sensor;

a case for containing the first board; and

a band attached to the case for fixing the case to a skin,

wherein the antenna is placed at a position opposed to the case and corresponding to an upper portion of the case on a first surface of the first board, and

the battery is placed at a position corresponding to a lower portion of the case on a second surface of the first board.

2. The sensor node according to claim 1, wherein the band is connected to the upper portion and the lower portion of the case to be wearable to an arm.

3. The sensor node according to claim 2, wherein, when one side is the upper portion of the case, the antenna is placed on a left side of the one side.

4. The sensor node according to claim 1, wherein the first board has a display unit placed in a lower portion of the antenna and an operation switch placed in a lower portion of the display unit, and

the case allows the display unit and the operation switch to be exposed to a surface of the case.

5. The sensor node according to claim 1, wherein the first board has a power supply circuit and a ground circuit formed thereon, excluding a no ground/power-plane area formed surrounding the antenna.

6. The sensor node according to claim 2, wherein the sensor comprises a light-emitting element and a light-receiving element placed at a position opposed to the skin, and

the light-emitting element and the light-receiving element are placed on an axis orthogonal to a center of a line connecting upper and lower directions of the case.

7. The sensor node according to claim 6, wherein the sensor is configured so that a plurality of light-emitting elements sandwich the light-receiving element.

8. The sensor node according to claim 6, wherein the case contains a second board on which the sensor is placed, and an opening through which the light-emitting element and the light-receiving element are opposed to the skin is formed on a bottom portion of the case.

9. The sensor node according to claim 8, wherein the second board is attached to a second surface of the first board, a power supply circuit and a ground circuit are formed at a position opposed to the antenna of the first board, excluding a no ground/power-plane area formed surrounding the opposed antenna, and the first board is placed on a surface side of the case.

10. The sensor node according to claim 9, wherein the second board is attached to an upper portion of the second surface of the first board, and members having a ground potential are placed in a lower portion of the second board on the second surface side of the first board.

11. The sensor node according to claim 10, wherein the members having the ground potential are a control apparatus for controlling the radio-communication circuit and the sensor, and a battery for supplying a power to the radio-communication circuit, the sensor, and the control apparatus.

12. The sensor node according to claim 1, wherein the antenna is a chip-type dielectric antenna composed of a high dielectric substance.

13. The sensor node according to claim 1, wherein the sensor includes a humidity sensor for measuring a humidity,

the case has a partition wall for partitioning a first space containing the humidity sensor from a second space containing the first board, and a window portion for introducing an outside air.

14. The sensor node according to claim 1, wherein the upper portion of the case corresponds to a 12 o'"'"'clock direction of a wristwatch.

15. The sensor node according to claim 7, wherein the case contains a second board on which the sensor is placed, and an opening through which the light-emitting element and the light-receiving element are opposed to the skin is formed on a bottom portion of the case.

16. The sensor node according to claim 15, wherein the second board is attached to a second surface of the first board, a power supply circuit and a ground circuit are formed at a position opposed to the antenna of the first board, excluding a no ground/power-plane area formed surrounding the opposed antenna, and the first board is placed on a surface side of the case.

17. The sensor node according to claim 16, wherein the second board is attached to an upper portion of the second surface of the first board, and members having a ground potential are placed in a lower portion of the second board on the second surface side of the first board.

18. The sensor node according to claim 17, wherein the members having the ground potential are a control apparatus for controlling the radio-communication circuit and the sensor, and a battery for supplying a power to the radio-communication circuit, the sensor, and the control apparatus.