1 Spring 2007 Engineering Expo Colby Austin - Biological Systems Engineering Laila Cornwall – Clothing, Textiles & Design Chris Curtis - Biological Systems.

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Spring 2007 Engineering Expo

Colby Austin - Biological Systems Engineering Laila Cornwall – Clothing, Textiles & Design Chris Curtis - Biological Systems Engineering

Lloyd Daugherty- Computer Engineering Jennifer Hasenoehrl - Mechanical Engineering

Jeff Otto - Electrical EngineeringBart Semmler - Mechanical Engineering

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Project Objectives

• Develop an infant monitor for in-home use to detect when baby stops breathing while sleeping.

• Product Goals:– Ease of Use – simple operation for caregivers– Reliability – no false alarms and durability– Compliance – IEC and Child Safety Regulations– Infant Safety – no shock or swallow hazards– Affordable off-the-shelf design, less than $300

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Why is this important?

• Over 4,500 infant deaths are reported every year in the United States which cannot be explained through any medical reasoning.

• Many medical experts believe that there is a link between the deaths and the babies’ breathing patterns.

• Some of these deaths could have been prevented had the discontinued breathing been detected and CPR administered.

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Concept Development

Ideas Considered:– Thermal imaging– Heart rate monitoring– Pressure sensors beneath the infant– Strain gages beneath the infant

– CO2 detectors

Final Design:– Wireless variable inductance strap

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System Architecture

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Infant Shirt Design

Areas of Focus:

• Functionality

- Ease of donning and doffing

• Safety - No access to internal hardware

• Manufacturability-Aesthetically pleasing & serve a function at the same time

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Infant Shirt ConstructionUse of the “French Seam” for lateral wire runs

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Modified Colpitts Oscillator Layout

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The State MachineInput: numeric representation of frequency Output: alarm

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The State Machine

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Transceiver

Digital Filter

Microcontroller

VariableOscillator

ComparatorCrystal

Oscillator

ComplexProgrammableLogic Device

Transmitter

Garment

Base

Unit

In Base Unit

On Garment

VariableInductance

Sensor

Amplifier& Speaker

Electrical Architecture

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ITEM AND FUNCTION

POTENTIAL FAILURE MODE(S)

POTENTIAL EFFECT(S) OF

FAILURE

SEVER

POTENTIAL CAUSE(S) OF

FAILURE

OCCUR

CURRENT DESIGN CONTROLS

DETECT

RN

OscillatorElectrical Failure

No Transmission 8

Bad Solder, Dead Battery 5 Warning 1 40

 Erroneous Readings

Processor Malfunction 8

 Hardware Damage 1

Comparator Accuracy 1 8

 Electrical Short Circuit

Electrical Shock  10 Insulation Wear 2

Proper Insulation/ Connections 5 40

 Disconnected from Shirt

No Transmission 8

Accidental Unsnapping 6 Warning Alarm 1 48

Shirt and Inductor

Sensor Bunched No Reading 5 Infant Movement 8

Proper Placement and Multiple Sensors 3 120

 Elastic Overstretched No Reading 5

Manufacturing Error 2 Proper Manufacturing 1 15

  Wire Broken No Reading 8 Fatigue 2Use 32 gage AWG wire 2 32

  Shirt Too Lose No Reading 5Inappropriate Sizing 3

Multiple Shirt Designs 2 30

Base Unit Receiver FailurePoor Signal Receiving 8

Improper Handling 2 Circuitry Casing 2 32

  No Alarm Broken Alarm 8Loose Connection 2 Soldering 3 48

TransmitterPoor Transmission

Transmitter Damage 5

Improper Handling 2

Small Transmitter Size 5 50

DFMEA (Design Failure Modes & Analysis)

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Product Component PricesItem Cost Electronics Cost

Thread $0.03 Crystal Oscillator $0.68

Wire $4.50 Pro-Logic Device $0.25

Elastic $0.05 Transceiver $3.23

Fabric $5.10 Transmitter $1.75

Button/Snaps $0.20 Receiver $2.47

Resistors $0.00

Capacitors $0.00

Inductors $2.00

Op Amp $3.79

Lithium Ion Battery $10.00

Battery Holder $0.73

Speaker $2.68

Audio Op Amp $0.58

AC Adapter $6.00

Screws/ Connecting Pieces $0.30

ASIC Production $0.50

Microphone $0.49

Microphone Holder $0.16

Total Garment Cost $9.88 Total Electronics Cost $35.59

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Final Design Rational

• Placed directly in the garment

• Less chance of interference

• Is unobtrusive and comfortable

• Allows for a wireless transmission

• Is cheap to produce

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Thanks to:• Idaho National Laboratory• University of Idaho• Professor Don Elger, Project Advisor• Mr. Dale Wahlquist• Mr. Gene Merrell• Gritman Sleep Center• Mr. Lloyd Gallup• Ms. Molly Steiner• Ms. Andrea Redmond• Professor Richard Wells• Mr. James FrenzelAnd everybody else who has assisted us in our project