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A Mobile Wireless Electrocardiogram System for Health Care Facilities. John Farner Jason Fritts Julian Jaeger Joe Richard. Georgia Institute of Technology School of Electrical and Computer Engineering. Project Overview.
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A Mobile Wireless Electrocardiogram System for Health Care Facilities John Farner Jason Fritts Julian Jaeger Joe Richard Georgia Institute of Technology School of Electrical and Computer Engineering
Project Overview • A mobile wireless EKG system that will track and store heart rhythm data, allow patients freedom of movement, and communicate with a central base station • Marketed to hospitals, nursing homes, and other health facilities to assist medical staff and increase patient care quality • Provide a reasonable alternative to conventional EKG systems at a reduced cost
Design Objectives • Safe for user • Reliable EKG data under a variety of circumstances • Base station interface • Easy to use mobile system • Lightweight and small size • Long range wireless data transfer
Stage 1:Measuring Potential Across the Human Body • Average Heartbeat • Men: 70 bpm • Women: 75 bpm • Up to 200 bpm Exercising • Chest Voltage, 0.5 mV to 5.0 mV
AD624ADPrecision Instrumentation Amplifier • Programmable gain between 1 and 1000 • CMRR exceeds 110 dB when the gain is set to 1000 http://www.ortodoxism.ro/datasheets/analogdevices/AD624BD.pdf
Linear Bandpass Filter • No battery power consumption • Loss of half the signal strength during testing • Bandwidth ≈ 1 Hz – 20 Hz
Reducing Input Signal Noise Before Filter After Filter http://www.analog.com/library/analogDialogue/archives/37-11/ecg.html
Stage 2:EKG Data Acquisition USB http://f.ipc2u.ru/files/products/34462/ebox2300.jpg http://robot.lonningdal.net/parts/phidgets.jpg • A Phidgets voltage sensor gathers data from the output of the front end circuitry • An onboard ADC converts analog signal to digital values • A C# OS subproject stores the digital data for later transmission to the base station
Mobile System Software Gather initial analog input values Store digitally as Y0 Start Initialize timer Store time as X0 Event Handling Have analog inputs changed? Has timer reached 5 sec? NO NO YES YES Read analog input Store digitally as Yi Run a second timer to wait 5 min between EKG readings Read system time Store time as Xi
Wireless Communication http://z.about.com/d/compnetworking/1/0/q/3/linksys_wrt54g.jpg http://www.embeddedpc.net/Portals/6/WiFi_Option.jpg • Files shared using Windows CE filesharing on a local area network. • eBOX uses a mini PCI 802.11g WiFi card • Base station connected to a Linksys 802.11g WiFi router • 802.11g WiFi Standard • Provides sufficient range (up to 38 meters) • Provides data transfer rate of 54 Mbps
Base Station GUI • Select patient from drop-down menu • Patient’s information is displayed in text boxes • Select desired heart data from list box to be graphed
Future Work • Integration of stage 1 and stage 2 • Data transfer • Connection between eBOX and base station • Automated file sharing • Mobile power options: • Use a 2nd voltage regulator or voltage supply • Use a 5V rail voltage • Packaging for mobility
“This year an estimated 1.2 million Americans will have a new or recurrent coronary attack.” http://www.americanheart.org/presenter.jhtml?identifier=4478