A Framework for Patient
Monitoring
A. L. Praveen Aroul, William Walker, Dinesh
Bhatia
Department of Electrical Engineering
University of Texas at Dallas
Outline





Introduction
Node architecture
Software Infrastructure
Network architecture
Microsoft HealthVault
Hardware – wrist module
 Biote is built into a wrist module
which houses an accelerometer, biopotential sensors interfaces, a
microcontroller, and an RF
communication transceiver.
Node Architecture - Biote
Sensing subsystem
 BMA 150 – accelerometer
 Primary used for Activity Monitoring
framework
 Provide a ranging form ±2g to ±8g
 Interfaced to MSP430 using SPI
 Bio-Potential sensors using UART
Processing subsystem





MSP430 microcontroller
16bit RISC CPU
120 kb ISP flash and 4Kb RAM
5 low power mode – save battery life
On chip Digital controlled oscillator
allows it wakeup within 1µs
Communication subsystem
 CC2420 RF transceiver
 Operate on 2.4 GHz ISM bands
 Extensive hardware support for
packet handling, data buffering, burst
transmission, data encryption,
authentication.
 Interface to MSP430 with SPI
Software Infrastructure
 Use TI-Z-Stack as the communication
protocol stack
 Compatible with ZigBee 2006 specification
 Low cost, low power and reliable device
monitoring and control
 Operating System Abstraction Layer of the
TI Z-stack provides scheduling, memory
management and messaging features
Network Architecture
 Network coordinator node
 Connect to the base station or mobile gateway,
which links to central server
 Initiate the network, allowing other nodes to join
the network by issuing the PAN address
 Performs routing operation as a router node
 Power is consumed mostly during the
transmission and reception of data on wireless
radio
 Preconfigured and fixed using traditional power
Bio-potential Sensor Interface
 SpO2 Data acquisition
 ECG measurement
 Blood pressure & Heart rate
SpO2 Data acquisition
 PM 31392B1 Micro Power Oximeter board
 Continuously monitor SpO2 and Pulse rate
 Transmit data as soon as readings are
received
 Require no command to start
communication
 Send data every 6 seconds initially
 Periodically check battery status, forward
low battery warning to the monitoring
station
ECG measurement
 GmBH EG1000 one channel ECG
module
 Continuously monitor cardiac rhythm
and pulse rate, sending out data
using on board serial port
 Programmable sample rate of
50,100,300
 Transmission is automatic once ECG
data bytes are received
BPM interface
 UA-767PC BPM provides BP and hear rate
reading
 The sensor node sends a start signal to BPM to
switch into communication mode and open the
communication port. BPM now ready to receive
 Sensor issues a command to take a
measurement
 Readings are sent to the sensor node when the
reading process has complete
 Limited processing is performed by the sensor
node on the data before previous data has
been transmitted
Turn on message
55
Open Comm Port message
02 43 50 43 30 35 3B
ACKnowledment
01 37 30 50 43 06
Take Reading
02 43 50 43 31 30 37
Data Message
38 30 33 43 33 43 34 36 5C 62
Microsoft Health Vault
 A free online database used to store
and share health related information
 Web based, it doesn’t support offline
access currently
 A certificate identifies the intended
application only, access is granted to
only the registered application
Records in Health Vault
 A record can contain personal
information such as name, blood
pressure readings, glucose level
readings, known allergies, etc.
 It s possible to view and change other
records depending on permission
granted
 Records can be shared
Master Record
 A Master Record is a person who is
interested in monitoring one or more
persons
 Two types of relationships
 Doctor/hospital to patient
 Family member to another member
 This system can be depicted as a tree with
the Master Record at the root and the
patient/member as the leaves
Basic System Interface
 1. Sensor to wireless sensor network
 2. Wireless sensor network to an
internet accessible device
 3. Internet accessible device to the
website
 4. Human to the website
 5. Website to Health Vault database
Question and Comment …