Team RCA April 8, 2013 - UMass Amherst

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)

3 Department of Electrical and Computer Engineering

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


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


System Integration in Helmet

Sensors

IC and battery


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


Calculating Risk

αH


Real-Time Algorithm

cos coscos sin

sin

H H

H H

H

HX H

H

α θα θ

α

=


User Interface

Home Page History Updating

Scrolling Accelerometer Graphs

Hit Histogram

User Settings


Hypothesis • Hit location & risk preserved

in initial time series acceleration data

Interpolation

• Quadratic • Iterate and connect

segments • Improves

Data Analysis


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


Data Analysis 3 ms vs. 1 ms


Data Analysis Theta +/- 30.8° Alpha +/- 35.0°


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


Demo

Demo


Questions

Thank You


Questions

Thank You


Backup Slides

Thank You


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


Material Costs

This cost could be reduced by $1,200 purchasing the RN-41 and designing the BlueTooth modem ourselves


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


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)


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


Lower frequency response • Vibrations

Mapping to graph

• More data points Cost

Single-Axis VS. Multi-Axis (Justin)


Measured System Energy Consumption (Tim)


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


Risk Function (Scott)

C1= -12.531 C2= 0.0020


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


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


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


Timeline


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


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


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)


Experiments • Threshold Estimation

- Mean, Standard Deviation

Hardware (Tim)


Battery System Power Requirements

• Maximum current ≈ 300 mA • 5 volts • 5 hour duration • Total energy consumption = 1390 mAh

USB Battery Pack • 2000 mAh • 5.5 V, 700 mA • Rechargeable

Documents

Team RCA April 8, 2013 - UMass Amherst