18-549 Spring 2007

HeartSaver: Wearable Real-time Cardiac Monitoring SystemChris Hoffman, Ryan Kellogg, Mike ZizzaMotivation Architecture

Results

This project addresses a need in the cardiac monitoring/diagnostics market for a device that:

•Can collect and analyze ECG signal data over extended periods of time (weeks – years)• Is comfortable for the patient and can be worn unnoticed during daily activities• Improves on robustness and accuracy of existing systems (electrodes stay intact, reduced sensitivity to noise, higher comfort)

http://www.ece.cmu.edu/~ece549/spring07/team5

Objective Forgettable, ambulatory ECG recording/diagnostics

Enables continuous, extended (> 48 hrs) monitoring Performs real-time analysis and alerts in emergency

Development Environment

Holter monitor – existing device (cumbersome,

electrode discomfort, 48 hour wear limit due to battery).

Hardware: • Gumstix: Basix 400xm-bt / Robostix• USB Serial Interface Assembly • Electrodes "Nikotabs"• ECG amplifier circuit • Laptop (Mac PowerBook) /

SmartPhoneSoftware:

• C/C++ ECG signal processing software

•Protocols: • Bluetooth • I2c (inter-integrated circuit) • Data Transfer over Serial

•Amplify and filter signal off body• Processing ECG signal on the fly•Display information to user graphically• Sample and store incoming signal

Heart signal is acquired from body via electrodes in shirt, transmitted over

bluetooth to console, ECG signal displayed and heart rate is calculated in real-time.

Amplification and filtering circuit [www.piconet.com]

Real-time monitoring, processing, and feedback about ECG data

now possible..

LocalCache

Text to Speech

Network Module

Input HandlerUPC

Request Handler

Local Cache

Database Driver

HTTP Handler

End-User

Local DB (Pricing) (RFID)

WWW Database

(UPC)

1. Bluetooth2. Application Protocol (TCP)3. Database Driver4. HTTP (TCP)

2

1

36620 Application

Remote Server – TCP Proxy

4

Aisle

Rack

Shelf

Product

Current Implementation

Sequential processing Products are processed one at a time

Blocking requests Finish current processing before handling next product

Caching Cache frequently used products on the phone Mitigates weak connectivity over the Internet

Concurrency Incoming calls, other applications may interfere Assume no other applications are running

Hardware Nokia 6620 smart phoneBluetooth serial module, Baracoda Pencil/IDBlue

Software TALKS C++ language Symbian OS on Nokia phone

Existing infrastructure UPC on products, cellphone’s Internet capability

Initial set of experiments Prototype completed, works with various products in Entropy Enabled our blind human subject to discover a product without assistance

Initial usability studies with blind human subject Limitations of COTS device (lack of aural feedback, timeouts) Never underestimate a blind person’s sensory capabilities