Mid-Year Status Report for

Instrumented Football Helmet

By

Louis Criso

Francis Kitrick

Ryan Lewis

Robert Sorbello

Submitted to

Department of Mechanical Engineering

VillanovaUniversity

Due: 12/8/2008

TABLE OF CONTENTS

Page #

Problem Statement 1

Design Tasks 1

Tasks Completed 2

Task Assignments 2

Schedule 4

Budget 5

Appendix A – Circuit Parts List 6

Appendix B – Apparatus Parts List 7

Appendix C – ARM Code 8

Appendix D – Circuit Design 10

Appendix E – Apparatus Analysis 11

Appendix F – Impact Analysis 14

Appendix G – Excel Apparatus Analysis 15

Appendix H – Excel Impact Analysis 16

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  1. Problem Statement: Design a working football helmet that can analyze the force of impact and determine if the impact is dangerous to the person. A microprocessor in the helmet will store data regarding the impact for analysis that can be later uploaded to a computer. A testing apparatus must be erected in order to properly test and calibrate the software for the helmet.
  1. Design Tasks: The following are the design tasks to be completed for completion of the project.
  2. Preliminary research – research must be preformed in order to conclude proper design.
  3. Component Research – need to research the proper components necessary to build the helmet most efficiently.
  4. Order Parts – all of the parts that were previously agreed upon must be ordered.
  5. PIC Programming – the PIC must be properly configured in order for it to convert and handle the incoming data from the accelerometer.
  6. GUI Programming – the graphical software must be produced so that the team trainer can accurately diagnose the player’s condition based on the information from the helmet.
  7. CircuitBuilding – a circuit must be built so that the accelerometer, PIC, and memory all function together inside of the helmet.

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  1. ApparatusBuilding – the testing apparatus must be built so testing of the helmet can be done.
  2. Sensor Calibration – the 3 axis accelerometer must be calibrated so that the software can have a reference point from which to interpret the data.
  3. Helmet Integration – all of the components must be integrated into the helmet.
  4. Final Testing – the completed helmet must be tested on a football field to ensure it functions properly.
  1. Tasks Completed: The following tasks have been completed and the documentation where available will be provided in the appendices.
  2. Preliminary research – Completed.
  3. Component research – Completed
  4. Order Parts – Completed. (See Appendix A for circuit parts list with links to websites where they were purchased. Appendix B contains the apparatus parts list with links to websites where they were purchased.)
  1. Task Assignments: The following tasks are either in progress or have yet to begin.
  2. PIC & GUI Programming – In process. ARM code has been written(See Appendix C for code). Waiting on circuit boards to finish programming the processor. This will be done by Louis Criso and Francis Kitrick.

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  1. CircuitBuilding – In process. Finalizing the schematic for the printed circuit board. (See Appendix D for preliminary circuit design). Once final, the boards can be ordered and the testing of the code can begin. This will be done by Robert Sorbello.
  2. ApparatusBuilding – In process. Finished theoretical analysis of pendulum apparatus (See Appendix E) and finished setup impact analysis sheet in MathCAD (See Appendix F). Also have placed the relevant data into excel sheets so data can be analyzed during calibration. (See Appendix G for Apparatus Sheet and Appendix H for Helmet data to be analyzed). Waiting for ordered parts to come in to begin building actual apparatus (Appendix B contains parts list for Apparatus). This will be done by Ryan Lewis.
  3. Sensor Calibration - Not Started. The accelerometers and pressure sensors will need to be calibrated so the software can have a reference point to start the data. This cannot be completed until the circuit boards have been built and properly programmed. All of the team members will be active during this task.
  4. Helmet Integration – Not Started. Once the circuits have been completed, programmed, and the sensors have been calibrated, the components must be installed into the helmet. A miniaturization of the components may need to take place in order to fit into the helmet. All team members will be working on this task.

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  1. Final Testing – Not Started. Once the components have been installed in the helmet, the helmet can finally begin being tested by the apparatus. The apparatus will strike the helmet at known forces and the helmet should be able to measure the severity of these impacts. All team members will be present during this task.
  1. Schedule: Time frame August 2008 – March 2009 (each | represents one week)

8/08 / 9/08 / 10/08 / 11/08 / 12/08 / 1/09 / 2/09 / 3/09
Prelim. Research (1) / | | | | / | |
Component Research (2) / | | / | |
Order Parts (3) / | / |
PIC Programming (4) / | | | | / | |
GUI Programming (5) / | | | | / | |
CircuitBuilding (6) / | | | | / | |
ApparatusBuilding (7) / | | / | | | | / | | / | |
Sensor Calibration (8) / | | / | | | |
Helmet Integration (9) / | | / | |
Final Testing (10) / | | / | |
Final Report (11) / | |

Page 4

  1. Budget: The following is the budget for our project.

Item / Budget / Actual
Accelerometer / $31.25
Wireless Adaptor / $70.00
PIC Microprocessor / $10.00
Li-Ion Battery and Manager / $10.00
Building Material / $30.00
Testing Material / $50.00
$201.25

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Appendix A – Circuit Parts List

Coridium ARMexpress LITE DIP Module,

Flexiforce Pressure Sensor - 100lbs,

Z-Axis Accelerometer – 250Gs,

2 X-Axis Accelerometers – 50Gs,

PC Card,

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Appendix B – Apparatus Parts List

Snap Hook: part # 18020450 Quantity: 2

Wire rope: # 01016WC619B Quantity: 30 feet

Wire Rope Clips: # 11016MC Quantity: 6

40 Pound Dumbbell: Local Gym Source

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Appendix C – ARM Code

'Code to write A/D ouput to flash memory

#include <SPI.bas>

#include <RTC.bas>

INPUT(3)

INPUT(8)

INPUT(9)

INPUT(10)

OUTPUT(1)

OUTPUT(2)

OUTPUT(4)

DIM X(256)

DIM Y(256)

DIM Z(256)

DIM Q(256)

threshold = 1000

i=$5000

j=$5100

k=$5200

c=0

WHILE i =< 0x6000 AND j =< 0x6000 AND k =< 0x6000

WHILE count < 256

Xhold=AD(2)

Yhold=AD(5)

Zhold=AD(1)

IF Xhold > threshold OR Yhold > threshold OR Zhold > threshold THEN

X(count)=Xhold

Y(count)=Yhold

Z(count)=Zhold

count = count + 1

ENDIF

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LOOP

WRITE (i, X, 256)

WRITE (j, Y, 256)

WRITE (k, Z, 256)

i = i + 0x300

j = j + 0x300

k = k + 0x300

LOOP

'Code to write to memory card

FREAD ($6000, X$, 256)

FREAD ($6100, Y$, 256)

FREAD ($6200, Z$, 256)

SPIOUT (1,2,4,0,256,X$)

SPIOUT (1,2,4,0,256,Y$)

SPIOUT (1,2,4,0,256,Z$)

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Appendix D – Circuit Design

Page 10

Appendix E – Apparatus Analysis

Instrumented Football Helmet

Apparatus Calculations

Acceleration due to gravity: g

Length of mass center to the piviot point: L

Circumference of the circle: C

Mass of the compound pendulum: m

Initial displacement from vertical axis: θ0

Moment of inertia: I

Natural Frequency of the pendulum: ωn

Period of the cycle: tp

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Frequency of the pendulum: f

Maximum Velocity reached by pendulum: Vmax

Torque on the pivot: τ

Angular acceleration: α

Force acting horizontally when pendulum is completely vertical: Fx

Distance above rest position on y axis: Δy

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P E of system: U

Power of impact: P

Arc Length:s

Linear Acceleration: A

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Appendix F – Impact Analysis

Instrumented Football Helmet

Impact Analysis

Head Acceleration (in G's): a (m/s2)

Time of Peak Impact: t (s)

Gadd Severity Index: GSI

Resultant Head Acceleration (in G's): a (m/s2)

Time of Impact: t (s)

Head Injury Criterion: HIC

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Appendix G – Excel Apparatus Analysis

Apparatus Characteristics:
Gravity= / 9.807 / m/s2 / 32.174 / ft/s2
Length= / 2 / m / 6.562 / ft
Mass= / 18.14 / kg / 40 / lbm
Moment of Inertia= / 72.56 / m2*kg / 1722.394 / ft2*lbm
Natural Frequency= / 2.214 / 1/s / 2.214 / 1/s
Period= / 2.837 / s / 2.838 / s
Apparatus Information:
Run # / Angle (Degrees) / Angle (Radians) / Vmax(m/s) / ά (rad/s2) / Fx (N) / Impact Energy (J)
1 / 30 / 0.524 / 2.319 / 2.452 / 88.949 / 47.668
2 / 35 / 0.611 / 2.705 / 2.813 / 102.039 / 64.345
3 / 40 / 0.698 / 3.092 / 3.152 / 114.351 / 83.241
4 / 45 / 0.785 / 3.478 / 3.467 / 125.794 / 104.211
5 / 50 / 0.873 / 3.865 / 3.756 / 136.279 / 127.095
6 / 55 / 0.960 / 4.251 / 4.017 / 145.726 / 151.721
7 / 60 / 1.047 / 4.638 / 4.247 / 154.065 / 177.899
8 / 65 / 1.134 / 5.024 / 4.444 / 161.231 / 205.431
9 / 70 / 1.222 / 5.411 / 4.608 / 167.170 / 234.108
10 / 75 / 1.309 / 5.797 / 4.736 / 171.837 / 263.711

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Appendix H – Excel Impact Analysis

Data Taken from Accelerometers
Limits: / 0.036 s / 1000 / 1000
0.015 s / 700 / 700
Run / Head Acceleration (in G's) (m/s2) / Time of Impact (s) / Severity Index / HIC
1 / 5 / 0.036 / 2.01 / 2.01
2 / 10 / 0.036 / 11.38 / 11.38
3 / 15 / 0.036 / 31.37 / 31.37
4 / 20 / 0.036 / 64.40 / 64.40
5 / 25 / 0.036 / 112.50 / 112.50
6 / 30 / 0.036 / 177.46 / 177.46
7 / 35 / 0.036 / 260.90 / 260.90
8 / 40 / 0.036 / 364.29 / 364.29
9 / 45 / 0.036 / 489.03 / 489.03
10 / 50 / 0.036 / 636.40 / 636.40

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