Instrumented Football Helmet

Instrumented Football Helmet

Final Proposal

Fall 2008

By:

Louis Criso (ECE)

Francis Kitrick (ECE)

Ryan Lewis (ME)

Robert Sorbello (ECE)

Executive Summary:

The ability to identify and treat head injuries before they are magnified is becoming the focus of many sports trainers and sports doctors. Our focus for this design project, is to aid in identifying if a hit to the helmet may be severe enough to cause a head injury.

First we must research the amount of force a human head can sustain without causing an injury of concern. The Gadd Severity Index[1] uses mathematical equations to establish a threshold of force that will cause damage to the head. We will need to find a way to accurately measure all forces the head will encounter. In order to do this, we will place a tri-axial accelerometer to measure the acceleration of the head in all three dimensions. By measuring the acceleration of the head, we can identify if there was any damage to the brain. When threshold is exceeded, there must be a warning mechanism that will alert the medical staff of a potential concussion. This warning can be in the form of a blinking light on the helmet or a buzzer located on the sidelines. Once the warning has been given, there must be a way to evaluate the data received from the accelerometer. There must be a way to take the data from the helmet and download it to externalsoftware to analyze the data. This must be done either by using a detachable chip such as a flash drive located in the helmet or a wireless transmitter that transmits the data directly to the computer. We will need to develop the software to analyze the data and resolve the forces sustained to the head. Once the software and data acquisition methods are set, we need to safely package all the components in the helmet safely. The packaging should not cause discomfort to the player and should also not diminish the structural integrity of the helmet. Once the packaging is finished we can test our prototype. Through testing in the lab and on the field, we can calibrate our hardware and software.

Table of Contents:

Introduction......

METHODOLOGY......

Design Approach Analysis......

Proposed Approach......

Task Description and Staffing......

Test and Evaluation Plan......

Administration......

Schedule......

Budget......

Facilities and Resources......

References......

Introduction

The impetus of this project is to help monitor and prevent head injuries occurring during football practices and games. According the National Football League (NFL) officials, there are about 160 concussions sustained every year[2]. Some of these concussions occur with the player not being diagnoses about until a few hours later. If left untreated, such an injury could become detrimental to the players long term health. For these reasons, our team decided to make sure that all these possible concussions will be detected for as soon as possible by creating a helmet that will measure the impact of a hit. If the impact force reaches to a threshold, the system will signal a trainerthat a potential concussion may have taken place so that the player can be taken out of the game or practice and the player treated as needed.[3]

In order to complete this project, all the members that are either electrical or computer engineers will have to obtain a full understanding of the sensors and accelerometers that will be placed in the helmet. Some prior work has been done in this area, and, in fact, there is an instrumented helmet in use in the Arena Football League (AFL) currently[4]. The AFL helmet turns on a light embedded in the helmet that can be observed by a trainer, indicating that a major helmet impact has occurred. Also there was work done by an earlier senior project group at Villanova.

Our goals for this project are very similar to the ones stated above. We will place a three axis accelerometer inside the helmet where there will also be a storage element to collect the data recorded. This data will later be exported via a USBconnection or a memory card so that the data can be uploaded onto a computer where the data can be further analyzed. This data will be put onto graphical software where the impact of a hit can be calculated using formulas used in prior Villanova classes. We would like to build upon the project conducted by the VillanovaUniversity students, make the design more riderous and add additional features, time permitting. Some ideas for additional functionality include using wireless techniques to send the information to the sideline for real time results. At the end of the project we will have a working football helmet that will be able to record information whether internally in the helmet or wirelessly so potential concussions will be able to be noticed by team trainers.

We are hoping that the technology that we develop will be able to be used for the Villanova Football team and perhaps have use in other leagues from Pop Warner football to the NFL. The product will be used by team trainers to alert them of a possible concussion that a player may have suffered. In the end, this helmet could possibly save many players careers, and even their quality of life.

The functional specifications of the project will include: a rechargeable long lifetime battery. The measurement system will cause no perceptible change in the weight and balance of the helmet. The system will be easy to use and be reliable. The system will include real time impact measurement software, a means to set and measure impact thresholds, and a means to alert trainers ofimpact that have a high probability of having caused an injury and possible concussions. It is anticipated that the system will include a three axis accelerometer, a microprocessor, A/D converters and possibly a wireless system to send the alert and / or data to a receiving station located on the sidelines.

METHODOLOGY

Design Approach Analysis:

Three different approaches were discussed in an effort to meet the goals of this project. Each approach differed in the way that the concussion data would be delivered and presented to the intended recipient. The approaches all varied in degree of difficulty.

Approach 1:

The first approach can also be seen as the simplest approach, and requires a 3 axis accelerometer[5]. This accelerometer would then be used to send analog signals to an A/D converter[6]embedded in a microprocessor. The microprocessor would then compute whether or not the data represents an impact large enough to cause a concussion. If an impact measurement has exceeded the threshold, the microprocessor would send a signal to an attached light which would flash after a dangerous hit. The pro of this approach is that it would be relatively simple to design and implement since there would be no need for significant memory on the helmet or to transfer the data to an external device. The con of this approach is that the data would only need to be represented by a simple on/off flashing light. This does not provide enough detail to team trainers in terms of the amount of hits that a player is taking or the intensity of such hits, but does signal a possible problem. Another issue is the difficulty in embedding a safe, easily observable light in the player’s helmet.

Approach 2:

The second approach would be the same as the first approach, except that the helmet would include significant memory storage on board and a light will not be used as a signal. The microprocessor would transfer the digital data to the on helmet’s memory card. The data would later be downloaded to a main sideline computer where it could be analyzed and displayed graphically by specially designed software. The pro of this approach is that the trainer would be able to visualize the data and observe every significant hit the player might have taken throughout the game. The con of this approach is that the trainer would not have any access to information during the game, which could be problematic if a player sustains a dangerously substantial hit.

Approach 3:

The third approach involves wirelessly transmitting the data to a sideline receiver. Under this approach, everything would be similar to approach 1 except that the data would be instantly sent to a special receiver which would be monitored by the team trainer. This would involve a one-way transmitter, and the data receiver would contain a numerical display which would correspond to the intensity of the current hit. The pro of this approach would be that the team trainer would receive instant feedback which could be crucial in the cases of extreme hits. The con of this approach would be that the team trainer couldbe overwhelmed with a large amount of information, and he/she would not receive the graphical representation that he would have using approach 2.

Proposed Approach:

After considering the possible approaches, the team decided that a 3 axis accelerometer[7] would be best for this project. The accelerometer would act as the lone sensor in the helmet. It would calculate the force in all three directions. The analog signals would then be converted to digital through the use of the A/D converter[8] on board the chosen microprocessor. It was tentatively decided to use the PIC 30F6011 as the microprocessor. This version of the PIC contains EEPROM memory which is non-volatile. This microprocessor also contains the necessary A/D converter which is needed to convert the signals from the 3 axis accelerometer. After the data is processed, it would be stored in an attached memory card.

The data would then be downloaded after the game to a computer. From there, a software program would analyze and graphically display the data so that the team trainer could review the information and make the proper judgment on the player’s health. As far as batteries are concerned, it is anticipated that the helmet will employa lithium battery[9] to power the PIC and the accelerometer.This approach was selected instead of the other approaches because it appears to be the most realistic design. It gives graphical information on the hits a player takes, instead of just providing an on/off light which doesn’t provide detail. However, it will not try to provide the unnecessary real time data whichmay proveconfusing for a trainer during a game when he/she has many other duties.

Task Description and Staffing:

Preliminary research – research must be preformed in order to conclude proper design. All group members will take part in this task.

Component Research – need to research the proper components necessary to build the helmet most efficiently. Louis Criso and Francis Kitrick will be responsible for this task.

Order Parts – all of the parts that were previously agreed upon must be ordered. Louis Criso, Francis Kitrick, and Rob Sorbello will be responsible for this.

PIC Programming – the PIC must be properly configured in order for it to convert and handle the incoming data from the accelerometer.Louis Criso and Francis Kitrick will be responsible for this.

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. Louis Criso, Francis Kitrick, and Ryan Lewis will be responsible for this.

CircuitBuilding – a circuit must be built so that the accelerometer, PIC, and memory all function together inside of the helmet. Rob Sorbello will be responsible for this.

ApparatusBuilding – the testing apparatus must be built so testing of the helmet can be done. Ryan Lewis is responsible for this building and the equations of motion for the apparatus.

Sensor Calibration – the 3 axis accelerometer must be calibrated so that the software can have a reference point from which to interpret the data. Ryan Lewis will be responsible for this using the apparatus and its equations of motion.

Helmet Integration – all of the components must be integrated into the helmet. All team members will participate in this task.

Final Testing – the completed helmet must be tested on a football field to ensure it functions properly. All team members will participate in this task.

Final Report – the final report will contain all possible information that is associated with the project in an effort to create an overview of all the activity which occurred during the helmet’s creation. All team members will participate in this task.

Test and Evaluation Plan:

The following aspects of this helmet system will need to be tested in order to ensure the proper operation of the helmet as a whole:

1. 3 axis accelerometer – the accelerometer itself must be tested to ensure that it is providing the necessary information.
2. A/D conversion of the accelerometer signal – it must be tested to make sure that the proper digital information is being stored based on the analog output of the accelerometer.
3. Transferring the information from the helmet to the main computer – this is a crucial aspect of the project because if the information cannot be taken successful from the helmet, then it is useless.
4. Graphically analyzing the downloaded information – it is imperative that accurate and readable graphical representations of the downloaded information are simulated so that the team trainer can make use of the data to make further conclusions on the health of the player.
5. Battery life – the helmet must show that it can operate for at least two times the length of an average football game. This is to take into account any unexpected delays, overtimes, or misuse (such as the player or trainer forgetting to turn off the helmet during a previously mentioned delay). This means that a fully charged helmet should work for around 5 to 6 hours before losing power.
6. Stability – all of the components of the helmet need to be tested in order to prove that they can withstand the impact of the hits which occur during a football game. The components must be secure, but also cannot be sheltered to the effect that they compromise the data that is recorded.

Administration

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) / | |

1. Preliminary and follow up research on football head/neck injuries. Gather statistics and also information on Head Injury Criterion (HIC) for later calculations. Figure out thresholds for what constitutes possible head trauma, injury, concussion, etc.

2. Design component research. Figure out with exact parts fit the specifications for the project. PIC should have analog to digital converter and ideally can accept 3 simultaneous inputs from accelerometer. Battery system needs to be able to power all the electronics for at least 5 hours. Memory card needs to be able to store all the data from the sensor at a high resolution

3. Ordering parts should be during the October Break.

4. PIC programming needs to take 3 inputs from accelerometer and convert into comparable force, also write memory interface exchange.

5. GUI programming needs to read the processed data off of the memory card and display on computer. Program should show chart of hits and how large impacts were. Another advanced goal in GUI software is to have a 3d model of head displayed showing force vectors of the hit.

6. Circuit prototyping/testing. Circuit takes output from accelerometer which is processed by the PIC. Data is stored on memory card. In final product this will all be on a printed circuit board.

7. ApparatusBuilding need to devise a way to build a testing apparatus with the ability to deliver enough force to test the helmet under accurate football conditions.

8. Sensor calibration/acceleration calculations. Use Acceleration Severity Index (ASI) to determine thresholds for forces. Measure known forces in order to make sure programming calculations and accelerometer are accurate[10].

9. Hardware integration w/ helmet. Everything has to be fitted securely within helmet. Placement of components to ensure reliability, safety, and accuracy

10. Testing of final product. “In game” simulation testing, use some sort of mechanical neck to test helmet.

11. Final Report and Presentation

Budget

Similar existing products cost thousands of dollars. Such as the Simbex HIT System. Goal is to create product that produces same results for far less.

Item / Budget / Actual
Accelerometer / $31.25
Wireless Adaptor / $70.00
PIC Microprocessor / $10.00
Li-Ion Battery and Manager / $10.00
Building Material / $50.00
Testing Material / $50.00
$221.25

Facilities and Resources

In order to implement this project, we will require microcontroller lab testing, access to circuit board printer/fabricator and also facilities to conduct impact testing and acceleration calculations. All the programming will be done C++ for the GUI software.

References

1. Hitachi H48C Tri-Axis Accelerometer Module,

1. Brain Injury in Sports,

1. 8-Bit A/D Converter,

1. Is the Lithium-ion the ideal Battery?,

1. Standard Performance Specification for Newly Manufactured Football Helmets,

1. Effects of Collisions on People,

1. Sports-Related Head Injury,

1. Caution Lights,

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[1] Reference # 6

[2] Reference # 7

[3] Reference #2

[4] Reference # 8

[5] Reference #1

[6] Reference #3

[7] Reference #1

[8] Reference #3

[9] Reference #4

[10] Reference #5