Glucose Monitoring Within a Handspring Visor

Members: Jeff Haar

Josh Lemke

Jeremy Saunier

Adam Smith

Advisors: Dr. John Estell

Dr. David Kisor

Diabetes in the United States

• Over 17 Million Americans have Diabetes

• Effects how the Body Regulates Blood Sugar Levels

• Currently No Cure

• Best Treated with Monitoring and Management

Proposed Device

• Take Current Meters and combine with a PDA

• Utilize Intuitive User Interface

• Obtain the Glucose Reading Accurately

Medical Issues

• Intended to Help Diabetics Manage Diabetes

• Must be Reliable

• Same Disclaimer as Common Meters– “Not Intended to Replace Test by Doctor”

• Would Require FDA Approval

Setbacks to our Design

• Abbott Laboratories– Slow to Support

• Development Board– Received with 3 Weeks

Left in the Quarter– Software Shipped Earlier

Analog Hardware

• Designed to use Proprietary “Strips”

• Patent Information was used

• Need Further Support of Abbott Laboratories

Examining Patents

• Patent Instructs– Apply 600 mV – Wait 5 – 60 Seconds – Measure Current

Through Circuit

Building Prototype

• Modeled Strip as Variable Resistance

• Added a 875Ω Resistor to Measure Current

• Measured Voltage Drop of 0 – 14 mV

~607 mV

875 Ω

R1 (~50kΩ – 10MΩ)(electrode modeled as a variable resistor)

Vout - to A/D converter

I1 (~0 - 16μA)

Digital Hardware

• Function Requirements

• Components Used

• Components Description

• Block Diagram

• Verification

Hardware Requirements

• Storage Memory

• Interface to Analog Hardware

• Interface to Visor

• Low Power Consumption

• Low Production Cost

Component Functionality

• CPLD Interface– Xilinx CoolRunner

• SRAM Temporary Storage– 4 mb Toshiba SRAM

• Flash ROM Store Program– 32 mb Toshiba CMOS FLASH MEMORY

Component Functionality Cont…

• 12 bit - A/D Converter – Maximum Resolution of .5mV

• Needed 500 for Glucose levels 0 – 500• Utilizes 1.15 V Reference

– Required Accuracy• 0-14mV For Analog Signal

– To obtain Required Accuracy• Gain of 20 (0 - 14 mV) x 20 = (0 – 280)mv• 280 ÷ .5 = 560 Discrete levels

Block Diagram

The CPLD Interface

• Communicate With Handspring– Triggering System

• A/D Driver– Used Xilinx Provided Program

• SRAM Driver– Used Xilinx Provided Program

• Flash Rom Drive– Untested

VerificationSimulated Verification

0

2

4

6

8

10

12

14

16

18

0 100 200 300 400 500 600 700

Glucose Reading mg/dl

Vo

ltag

e (m

V)

Calculated

Measured

Software Development

• Functional Requirements

• Non-Functional Requirements

• GUI Functions

• Program Overview

Functional Requirements

• Information Storage– Glucose Reading– Date/Time– Comments– Type

• Information Retrieval– Graphically Display Data

• Backup to PC

Non-Functional Requirements

• Simple and Intuitive to Use

• Quick to Input Reading

• Palm Appearance

GUI Interface

• Built our own GUI– Buttons– Drop Down Lists– Graphs

Program Flow

Future Considerations

• Production Costs

• Hardware Improvements

• Software Improvements

Estimated Production Cost

Item SourceApproximate

Price

Module Case Novus Technology $ 0.72

Xilinx Chip XCR3064XL-VQ100 Xilinx $ 4.15

Springboard connectorsJST Products or ATL technology

$ 1.00

EEPROM Memory ~1 MB Mouser (Distributor) $ 5.00

Strip reader A/D Converter Abbott Unknown

Circuit board and assembly Springboard Partner $2

Resistors and Other Components Unknown $1

Total ≈ $15

Future Software Improvements

• Web Interface– Ecivon SQL database– Over both hot sync feature and wireless web access

• PC Interface– Conduit to upload to PC

• Help information within program• Allow multiple users• Manual Entries

Future Hardware Improvements

• Purge design off development board– Create printed circuit board for module – Use CPLD to average and store readings / eliminate SRAM as

temporary storage location

Future Hardware Improvements

• Initialization– Store software in module’s Flash ROM– Begin reading immediately when strip is inserted

• Improve Power consumption– Test power consumption of module

• Adapt design to meet specs of partnering Drug Company – Can’t create our own strips

Conclusion

• Currently have proof of concept device• Software functional• Accurate hardware depends on proprietary strips

For Further Information:

• http://www2.onu.edu/~stu5583/senior

Any Questions?

• References– http://www.niddk.nih.gov/health/diabetes/pubs/dmstats/dmstats.htm – Bayer, U.S. Patent No. 5,120,420 (June 9, 1992)

Software Decision Matrix

Code Warrior Web Clippings Pocket C

Functionality 10 3 7

Usability 1 10 7

Price 1 5 7

Time Frame 10 10 7

Dev. Board 5 0 10

Total 27 No consideration 38

Software Block Diagram

Start

Databasepresent

Welcome screen

Create database

Button tapExit

Enter commentsand type

Insert Stripe

Do you want tosave

Store record tothe database

View data screen

Button Tap

Button TapGoto next or

previous record

Change to a newdate

Sure want todelete

Delete record andgoto the next

record

Graph screen

Button tap

Button tap

Take lines away orput lines back

Show specificreading

information

Goto the next orprevious time

frame

Zoom in or out today, week, or

month

No

Yes

No

View Data

Create Data

Exit

DonePick Date

Next/Previous Delete

Graph

+/-

ClickPointDone

Lines

Yes

No

GlucoMon Flow Chart

Other

Other

View readinginformation

Yes

Software Verification

• Sample Database Created– 2404 Records Spanning 2+ Years– 109 Kilobytes in size– Tested Leap Year

• Platform Testing– Used POSE to Test Different Operating

Systems

• Total Installed Program Size– 117 Kilobytes

Extended Economic Information

Item SourceApproximate

Price

Code Warrior Software Development System Metrowerks $499

Palm OS Emulator Palm Free

Handspring Visor PDA Visor $200.00

Insight Technologies Development board Included PocketC Environment

Insight $ 350.00