1 spring 2007 engineering expo colby austin - biological systems engineering laila cornwall –...
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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