team rca april 8, 2013 - umass amherst
TRANSCRIPT
1 Department of Electrical and Computer Engineering Department of Electrical and Computer Engineering Advisor: Professor Hollot
Team RCA April 8, 2013
Final Project Review
2 Department of Electrical and Computer Engineering Department of Electrical and Computer Engineering Advisor: Professor Hollot
Kenneth Van Tassell, EE User Interface & Communication
Scott Rosa, CSE Server & Data Analysis
Justin Kober, EE Sensor Network & Power
Timothy Coyle, EE Impact Processing & Communication
RCA (Real-Time Concussion Analyzer)
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Our Solution: Block Diagram
Data Processing
Server
Player DB
Impact DB
GUI
TX/RX Settings
History Server Interface
Impact Data Collection Data Analysis
User Interface
Power Supply
Sensors
Processing TX/RX
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Bessel filter: 3 dB cutoff at 400 Hz Individual sensitivity Placement location and error
• Shifting during impacts
Custom pad for battery Battery test
Sensors & Battery
Sensor Theta Alpha
0 0 20
1 -90 15
2 -180 20
3 90 15
4 75 50
5 -69 50
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System Integration in Helmet
Sensors
IC and battery
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Impact Processing & Communication
SRAM buffer for samples for 20 ms 1.5 kHz sample rate Threshold triggering at 10 g 154 Kbps at 30 m
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Real-Time Algorithm
cos coscos sin
sin
H H
H H
H
HX H
H
α θα θ
α
=
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User Interface
Home Page History Updating
Scrolling Accelerometer Graphs
Hit Histogram
User Settings
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Hypothesis • Hit location & risk preserved
in initial time series acceleration data
Interpolation
• Quadratic • Iterate and connect
segments • Improves
Data Analysis
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Map location correctly and risk will follow
MATLAB code RCA to laptop 160 impact tests
• 10 identical tests in 16 locations Peak sensor values
Data Analysis
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Requirement Specifications
Specification Goal Actual Weight < 5% increase (102 g) 6.2% (120 g) Range 25 m 30 m
Response Time < 2 s < 5 s Battery Life > 5 hr. > 5 hr.
Cost < $5000 per team $5040 Power Consumption < 2 W 1.39 W Acceleration Range +/- 70 g +/- 84 g
Sensitivity Detect only collisions Triggers at 10 g Durable Packaging Stable & Waterproof Stable & partially water
resistant
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Current concussion detection • Train coaches to recognize symptoms
Players may hide or not experience symptoms
right away RCA will monitor each player and alert the
coach with the risk of concussion after each collision
Customer feedback
• College trainers and high school athletic director
Concussion Detection in High School Football
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Material Costs
This cost could be reduced by $1,200 purchasing the RN-41 and designing the BlueTooth modem ourselves
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Requirements Analysis: Specifications
Real-Time continuous impact measurements Player specific adaptability Equipment weight increase less than 5% Effective range 150 m Responds in under two seconds Robust
• Interference • Durable
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Weight Analysis of Riddell Speed Helmet Weight (g)
Helmet w/out our system 1927 Average of offical weight provided from riddell
Our System (Sensors, Battery, Protoboard) 120
Helmet w/ our system 2047
Sensors & Protoboard 45
Battery Unit 75
Empty Battery Case 30
Battery & PCB 45
Percent increase of player's equipment 6.2 1.2% over spec
Percent increase of player's equipment 4.7 0.3% under spec
If we took the components out of the battery case and intergrated them into our system.
Weight Analysis (Justin)
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Worst Case Power (Justin)
Worst Case Power Analysis Device Max Voltage (V) Max Current (mA) Max Power (W)
ATmega32U4 5 200 1
BlueSMiRF Gold 3.3 100 0.33
ADXL 193 5 2 0.01
Total Power (W)
1.39
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Lower frequency response • Vibrations
Mapping to graph
• More data points Cost
Single-Axis VS. Multi-Axis (Justin)
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Data Processing and Storage (Scott) Requirements From MDR
• Calculate a magnitude hit vector from the accelerometer data
• Calculate risk for each hit as well as cumulative risk • Be able to store raw accelerometer data
Accomplished • Calculates the hit vector in an average of 411.6 ms.
The overall program calculates risk in an average of 1.06 s
• Tested and graphed data • Set up server with database to store raw
accelerometer data and hit data
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Computational Analysis (Scott)
Storage and computation can be done on a phone
Server hosts
MySQL database
Max phone memory size: 64 GB Min phone memory size: 2 GB Top Ten Paid apps in Itunes 11/26/12 Max App memory size: 791 MB Min App memory size: 3.1 MB Average of max and min memory size: 397.05 MB
Size of Entry in table is
40 Bytes 0.00004 MB 9926250 hits in total
90 Avg hits per college season per player: 1177 seasons played by college player: 4 hits for college team in 1 years 423720 Team data for 4 years 17 MB Team data per year 4 MB Store data for 99 teams per year Store data for 23 college teams for 4 years
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Application / User Interface and UI Communication (Kenny)
Design Requirements • Simple Operation / User Friendly • Displays Meaningful Information • User Adaptable
− Coach vs. Trainer • Player Adaptable
− Adaptive Threshold Monitoring
Challenges • Improving Processing • Maintaining Continuity • Redesigning Bluetooth Parsing for Variable Hits
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Fully Integrated and Wearable Helmet • Stable battery • Player specific adaptability
Reliable User Friendly Android Application • User specific settings
Risk Calculation with Confidence Interval • Probability of Error
DEMO
• Impact Dummy • Server, Impact Location & Application
Demo Day
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Sensors ADXL 78 MEMS Accelerometer
• +/- 70 g range − +/- 20% above spec
• Ideal 27 mV/g sensitivity • 2-Pole Bessel Filter
− 3 dB cutoff at 400 Hz
Sensitivity Characterization
Vdd Up (mV) St Dev Up Vdd Dn (mV) St Dev Dn Mean Sens Min Sens Max Sens Sensor 0 2441.9 0.1 2497.1 0.2 27.6 27.5 27.7 Sensor 1 2467.2 0.1 2522.2 0.1 27.5 27.4 27.6 Sensor 2 2485.3 0.1 2540.6 0.1 27.6 27.6 27.7 Sensor 3 2479.0 0.1 2534.2 0.1 27.6 27.5 27.7 Sensor 4 2464.1 0.2 2519.7 0.1 27.8 27.7 27.9 Sensor 5 2480.2 0.2 2535.4 0.1 27.6 27.5 27.8
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Placement of Sensors Location and Error in placement
Shifting during impacts • Density of pads
• Pads sealed with glue
• Negligible movement
Theta Alpha
Sensors Theta Alpha Error Min Max Min Max
0 0 20 5% -9 9 15.5 24.5
1 -90 15 5% -99 -81 10.5 19.5
2 -180 20 5% 171 -171 15.5 24.5
3 90 15 5% 81 99 10.5 19.5
4 75 50 5% 66 84 45.5 54.5
5 -69 50 5% -78 -60 45.5 54.5
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ADC Sample Error • Function generator sine &
square waves − 4.5 kHz sample rate
• Changing ADC channel too soon
ADC Solution
• ADC interrupts in code
Impact Processing & Communication Experiments (Tim)
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Experiments • Threshold Estimation
- Mean, Standard Deviation
Hardware (Tim)