DocumentCode :
3204888
Title :
A Battery-Free Tag for Wireless Monitoring of Heart Sounds
Author :
Mandal, Soumyajit ; Turicchia, Lorenzo ; Sarpeshkar, Rahul
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Massachusetts Inst. of Technol., Cambridge, MA, USA
fYear :
2009
fDate :
3-5 June 2009
Firstpage :
201
Lastpage :
206
Abstract :
We have developed a wearable, battery-free tag that monitors heart sounds. The tag powers up by harvesting ambient RF energy, and contains a low-power integrated circuit, an antenna and up to four microphones. The chip, which consumes only 1.0 uW of power, generates digital events when the outputs of any of the microphones exceeds a programmable threshold voltage, combines such events together by using a programmable logic array, and transmits them to a base station by using backscatter modulation. The chip can also be programmed to trade-off microphone sensitivity for power consumption. In this paper, we demonstrate that the tag, when attached to the chest, can reliably measure heart rate at distances up to 7 m from an FCC-compliant RF power source. We also suggest how delays between signals measured by microphones at the wrist and neck can be used to provide information about relative blood-pressure variations.
Keywords :
biomedical electronics; biomedical ultrasonics; body area networks; cardiology; energy harvesting; low-power electronics; microphones; patient monitoring; wireless sensor networks; FCC-compliant RF power source; ambient RF energy; antenna; backscatter modulation; battery-free tag; energy harvesting; heart sound monitoring; low-power integrated circuit; microphones; neck; power consumption; programmable logic array; programmable threshold voltage; relative blood-pressure variation; wearable sensors; wireless monitoring; wrist; Base stations; Biomedical monitoring; Heart; Microphone arrays; Power generation; Programmable logic arrays; Radio frequency; Radiofrequency integrated circuits; Semiconductor device measurement; Threshold voltage; battery-free; heart sounds; low power; wearable sensors; wireless health monitoring;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Wearable and Implantable Body Sensor Networks, 2009. BSN 2009. Sixth International Workshop on
Conference_Location :
Berkeley, CA
Print_ISBN :
978-0-7695-3644-6
Type :
conf
DOI :
10.1109/BSN.2009.11
Filename :
5226893
Link To Document :
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