Title: A Mobile Wireless Electrocardiogram System for Health Care Facilities
1A 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
2Project 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
3Design 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
4Two Stage Implementation
5Stage 1Measuring 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
6Front End Circuitry
7AD624ADPrecision 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
8Linear Bandpass Filter
- No battery power consumption
- Loss of half the signal strength during testing
- Bandwidth 1 Hz 20 Hz
9Linear Bandpass Filter Bode Plot
10Reducing Input Signal Noise
Before Filter
After Filter
http//www.analog.com/library/analogDialogue/archi
ves/37-11/ecg.html
11Stage 2EKG Data Acquisition
USB
http//f.ipc2u.ru/files/products/34462/ebox2300.jp
g
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
12Mobile 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
13Wireless Communication
http//z.about.com/d/compnetworking/1/0/q/3/linksy
s_wrt54g.jpg
http//www.embeddedpc.net/Portals/6/WiFi_Option.jp
g
- 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
14Base Station GUI
- Select patient from drop-down menu
- Patients information is displayed in text boxes
- Select desired heart data from list box to be
graphed
15Design Choices
16Project Timeline
17Future 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
18- This year an estimated 1.2 million Americans
will have a new or recurrent coronary attack.
http//www.americanheart.org/presenter.jhtml?ident
ifier4478