Controller for sensor node, measurement method for biometric information and its software

• US 20060229520A1
• Filed: 08/25/2005
• Published: 10/12/2006
• Est. Priority Date: 04/08/2005
• Status: Abandoned Application

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Shimura, Takanori, Kuriyama, Hiroyuki, Yamashita, Shunzo, Aiki, Kiyoshi
• Application Number:
  US11/210,740
• Publication Number:
  US 20060229520A1
• Time in Patent Office: Days
• US Class Current: 600/503
• CPC Class Codes: A61B 2560/0209 adapted for power saving
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/681 Wristwatch-type devices

Abstract

The precision of measuring biometric information is enhanced while suppressing the consumption of a battery in a sensor node. In a method of measuring the biometric information in a sensor node including a controller for driving a sensor to measure biometric information, the controller supplies power from a battery to an acceleration sensor for detecting the movement of a living body to detect the movement of the living body, the controller determines whether or not measurement by a pulsebeat sensor is possible based on the detected movement of the living body (P330), and shuts off power to the acceleration sensor having a power consumption lower than that of the pulsebeat sensor when the determination results show that measurement is possible, and thereafter supplying power to the pulsebeat sensor having a power consumption larger than that of the acceleration sensor to measure the biometric information (P340).

Claims

1. A controller for a sensor node to be worn by a living body, comprising:

a controller for measuring biometric information by driving a sensor;

a radio communication circuit for transmitting the biometric information obtained by the controller; and

a battery for supplying power to the controller, the radio communication circuit, and the sensor,

wherein the sensor comprises a first sensor for detecting a movement of the living body, and a second sensor for measuring the biometric information,

wherein the controller comprises a measurement start determination part for supplying power from the battery to the first sensor to detect the movement of the living body and determining whether or not measurement by the second sensor is possible based on the movement of the living body, and a biometric information measurement part for starting a supply of the power to the second sensor to measure the biometric information after shutting off the power to the first sensor when determination results of the measurement start determination part show that measurement is possible, and

wherein a power consumption of the first sensor is lower than a power consumption of the second sensor.

2. The controller for a sensor node according to claim 1,

wherein the biometric information measurement part includes an adjustment part for adjusting a state of the second sensor to optimize a measurement state of the second sensor, and

wherein the adjustment part continues measurement when measurement results of the second sensor show that the sensor node is worn, while stopping measurement when the measurement results of the second sensor show the sensor node is not worn and shutting off power to the second sensor.

3. The controller for a sensor node according to claim 2,

wherein the second sensor comprises a light-emitting element and a light-receiving element for measuring a pulsebeat from a bloodstream under a skin of the living body, and

wherein the adjustment part gradually increases a light quantity of the light-emitting element to optimize the light quantity, and determines whether the sensor node is worn or not worn based on sensor data after a measurement start of the light-receiving element.

4. The controller for a sensor node according to claim 1,

wherein the first sensor comprises an acceleration sensor for detecting the movement of the living body based on an acceleration, and

wherein the measurement start determination part determines that biometric information can be measured by the second sensor when a detected value of the acceleration is less than a threshold value.

5. The controller for a sensor node according to claim 1,

wherein the controller further comprises a microcomputer for controlling the sensor and the radio communication circuit, and a clock circuit for applying an interrupt to the microcomputer at a previously set period, and

wherein the microcomputer waits in a standby state until an interrupt is applied from the clock circuit and the microcomputer is started when the interrupt is applied from the clock circuit to start supplying power to the first sensor.

6. The controller for a sensor node according to claim 1,

wherein the controller further comprises a communication processing part for shutting off power to the second sensor after measuring the biometric information, and supplying power to the radio communication circuit to transmit the measured biometric information.

7. The controller for a sensor node according to claim 6,

wherein the communication processing part receives information to the sensor node after transmitting the biometric information, and shutting off the power to the radio communication circuit after completing the reception.

8. The controller for a sensor node according to claim 5,

wherein the controller further comprises a switch for conducting a transmission in a case of emergency, determines whether or not the switch is operated again after a predetermined period of time from a time when the switch is operated, and supplies power to the radio communication circuit when a switch is operated as a result of the determination to perform communication for emergency.

9. A program for causing a microcomputer to execute processing of measuring biometric information from a sensor of a sensor node worn by a living body, the program comprising steps of:

supplying power from a battery to a first sensor for detecting a movement of the living body to detect the movement of the living body;

determining whether or not measurement by the second sensor is possible based on the detected movement of the living body; and

shutting off power to the first sensor having a power consumption lower than that of the second sensor when the determination results show that measurement is possible, and supplying power to the second sensor having a power consumption larger than that of the first sensor to measure the biometric information.

10. The program according to claim 9,

wherein the step of measuring the biometric information comprises a step of continuing measurement when measurement results of the second sensor show that the sensor node is worn, while stopping measurement when the measurement results of the second sensor show the sensor node is not worn and shutting off power supply to the second sensor.

11. The program according to claim 9,

wherein the second sensor comprises a light-emitting element and a light-receiving element for measuring a pulsebeat from a bloodstream under a skin of the living body, and

wherein the step of measuring the biometric information comprises steps of:

gradually increasing a light quantity of the light-emitting element to optimize the light quantity; and

determining whether the sensor node is worn or not worn based on sensor data after a measurement start of the light-receiving element.

12. The program according to claim 9,

wherein the first sensor comprises an acceleration sensor for detecting the movement of the living body based on an acceleration, and

wherein the determining step comprises a step of determining that biometric information can be measured by the second sensor when a detected value of the acceleration is less than a threshold value.

13. The program according to claim 9,

wherein the sensor node comprises a clock circuit for applying an interrupt to the microcomputer at a previously set period, and

wherein the step of detecting a movement of the living body comprises steps of:

waiting in a standby state until an interrupt is applied from the clock circuit; and

starting the microcomputer when an interrupt is applied from the clock circuit to start supplying power to the first sensor.

14. The program according to claim 9, further comprising the steps of:

shutting off power to the second sensor after measuring the biometric information; and

supplying power to the radio communication circuit to transmit the measured biometric information.

15. The program according to claim 9,

wherein the step of transmitting the biometric information receives information to the sensor node after transmitting the biometric information, and shutting off the power to the radio communication circuit after completing the reception.

16. The program according to claim 13,

wherein the sensor node comprises a switch for conducting a transmission in a case of emergency, and

wherein the program comprises steps of waiting until a predetermined period time elapses after the switch is operated, determining whether or not the switch is operated again after the predetermined period of time elapses, and supplying power to the radio communication circuit when a switch is operated as a result of the determination to perform communication for emergency.

17. A method of measuring biometric information in a sensor node including a controller for driving a sensor to measure the biometric information,

the method of measuring the biometric information comprising steps of:

detecting a movement of a living body by a first sensor for detecting the movement of the living body when power is supplied from a battery to the first sensor by the controller;

determining whether or not measurement by the second sensor is possible based on the detected movement of the living body by the controller; and

shutting off power to the first sensor having a power consumption lower than that of the second sensor when the determination results show that measurement is possible, and supplying power to the second sensor having a power consumption larger than that of the first sensor to measure the biometric information.

18. The method of measuring the biometric information according to claim 17,

wherein the step of measuring the biometric information comprises a step of continuing measurement when measurement results of the second sensor show that the sensor node is worn, while stopping measurement when the measurement results of the second sensor show the sensor node is not worn and shutting off power to the second sensor.

19. The method of measuring the biometric information according to claim 17,

wherein the second sensor comprises a light-emitting element and a light-receiving element for measuring a pulsebeat from a bloodstream under a skin of the living body, and

wherein the step of measuring biometric information comprises steps of:

gradually increasing a light quantity of the light-emitting element to optimize the light quantity; and

determining whether the sensor node is worn or not worn based on sensor data after a measurement start of the light-receiving element.

20. The method of measuring the biometric information according to claim 17, wherein the first sensor comprises an acceleration sensor for detecting the movement of the living body based on an acceleration, and

wherein the determining step comprises a step of determining that the biometric information can be measured by the second sensor when a detected value of the acceleration is less than a threshold value.

21. The method of measuring the biometric information according to claim 17,

wherein the controller comprises a microcomputer for controlling the sensor, and a clock circuit for applying an interrupt to the microcomputer at a previously set period, and

wherein the step of detecting the movement of the living body comprises steps of:

causing the microcomputer to wait in a standby state until an interrupt is applied from the clock circuit, and starting the microcomputer when an interrupt is applied from the clock circuit to start supplying power to the first sensor.

22. The method of measuring the biometric information according to claim 17, further comprising the steps of:

shutting off power to the second sensor by the controller after measuring the biometric information; and

supplying power to the radio communication circuit to transmit the measured biometric information.

23. The method of measuring the biometric information according to claim 17,

wherein the step of transmitting the biometric information comprises a step of receiving information to the sensor node after transmitting the biometric information, and shutting off power to the radio communication circuit after completing the reception.

24. The method of measuring the biometric information according to claim 21,

wherein the controller comprises a switch for transmitting in a case of emergency, and

wherein the controller comprises steps of waiting until a predetermined period time elapses after the switch is operated, determining whether or not the switch is operated again after the predetermined period of time elapses, and supplying power to the radio communication circuit when a switch is operated as a result of the determination to perform communication for emergency.