Gyroscopic Joint Range of Motion Device

EPICS 151

Spring 2013

4/29/2013

Monday, April 29, 2013

Doctor’s Supply Inc.

4680 Edison Avenue Suite A

Colorado Springs, CO 80915

Dear Mr. Brunelle and Dr. Bach,

Grizzly Design submits this report to explain the team’s final design option for the range of

motion device and potential alternatives. On January 9, 2013, Doctor’s Supply Inc. asked us to

develop a more accurate and reliable electronic joint range of motion device. Since then, Grizzly

Design has developed a simple, easy to use, gyroscope device to solve this problem.

Grizzly Design has engineered a compact, reliable, and easy to use device to accommodate

Doctor Supply Inc.’s needs. The chosen design uses a gyroscope to reliably record maximum

and minimum angles of joint movement. Such a customizable and compact design will be easily

marketed and will not require the assistance of a specialist. Also included are alternative designs

that may also appeal to Doctor Supply Inc.

Grizzly Design is very excited to be working on this project and, with your permission, would

like to continue development of our design. You may contact Grizzly Design at

jomeyer@mines.edu.

Thank you for your time,

Joe Meyer

Liaison, Grizzly Design

cc: Bob Neukirchner

Quinn Wolf

Loren Awalt

Tyler Rockley

Daevin Dev

Gyroscopic Joint Range of Motion Device

Design Report

Loren Awalt//Daevin Dev//Joe Meyer//Tyler Rockley//Quinn Wolf

Colorado School of Mines

EPICS 151 Section J

4/29/2013

Design Report for Gyroscope Range of Motion Device:

Executive Summary

Doctor’s Supply Inc. approached Grizzly Design with the task of researching and

designing a more reliable and easier to use smart device to measure joint range of motion in

physical joint therapy. The team developed a user friendly smart device with the capability of

automatically recording measurements while still being accurate and reliable. The main focus of

the design was to obtain the best data set possible while measuring joint range of motion. The

final design chosen revolves around the use of a gyroscope to measure the angle of joint motion.

The gyroscope is accurate to a hundredth of a degree and more precise than any other industry

standard angle measurement device. In fact, in preliminary testing, the device matched the

deviation in industry standard digital protractors that can cost at least twice as much.

Implementing a gyroscope allows for a super compact, versatile, and accurate design, which will

earn the approval of Doctor Supply Inc. and all physical therapists working with joint range of

motion.

The gyroscope itself and its necessary components are encased inside a sturdy and

durable ABS plastic box to protect it from the elements. All of the electronic components

interact through specially designed software which is fully customizable and adaptable to any of

the client’s or patients’ needs. The protective box for the gyroscope is made of durable,

lightweight material which is attached to a comfortable, lightweight strap. The strap wraps

around the wrist like a watch band and keeps the gyroscope and components securely attached to

the wrist. If a therapist wishes, a free weight can be added to ensure a constant and consistent

(between patients) force is applied to the joint. In this optional case, the patient will lie on their

back, hold the dumbbell at a ninety degree angle and slowly lower their arm to their shoulder.

Some of Grizzly Design’s alternate designs include an external frame goniometer brace

that was unoriginal, bulky, and less accurate. The team also worked on a simplified motion

capture device that used infrared and camera sensors to detect the range of motion. It was too

complex, difficult to use, and only accurate in certain circumstances. Fixing these problems, the

final design is very accurate and reliable, compact, inexpensive, versatile (it can be adapted to

any limb on any patient and can be customized to fit the patient’s exact needs), and easy to use.

An enormous advantage the final design has to other potential designs is its ability to be

marketed. The final cost is estimated and production is estimated to be only $15. Along with its

customizability and accuracy, the final gyroscope design will grasp the interests of all physical

therapists and promote Doctor Supply Inc.

Table of Contents

Introduction………………………………………………………………………………….…….1

Alternate Designs………………………………………………………………………………….1

External Frame Goniometer Brace…………………………………………..……………1

Simplified Motion Capture Using Infrared Mapping…………………………..…………2

Final Design……………………………………………………………………………………….2

Gyroscope…………………………………………………………………......…………..2

Electronics and Software………………………………………………………………………….3

Introduction…………………………………………………………………………..……3

Overall Physical Subsystem Analysis…………………………………..…………………3

Connections to Other Systems………………………………………………………….…3

How it Meets Client’s Requirements…………………………………………………...…3

The Gyroscope Unit…………………………………………………………………….…3

The Analog-to-Digital Converter……………………………………………….…………4

USB Cable and Port Specifications………….……………………………………………4

Software…………………………………………………………...………………………4

A Note about Customization………………………………………………………………5

Assembly…………………………………………………..………………………………5

Test Results………………………………………………..………………………………5

Summary……………………………………………………………..……………………6

Housing and Mounting…………………………………………………...……………………….6

Introduction……………………………………………………………..…………………6

Housing……………………………………………………………………………………6

Wrist Strap……………………………………………………...…………………………7

Assembly………………………………………………………..…………………………7

Summary………………………………………………………………..…………………7

Force System…………………………………………………………………………...………….8

Dumbbell…………………………………………………………………………..………8

Optional Constant-Tension Spring (used only in certain circumstances) ………...………8

Instruction Manual……………………………………………………………………..………….8

Introduction………………………………………………………………..………………8

Paper-Based Instruction Manual………………………..…………………………………9

Computer-Based User Interface Instructions……………….……………………………10

Summary…………………………………………………………………………………10

Operation and Maintenance………………………………………………………………..…….10

Operation…………………………………………………………………………………10

Maintenance…………………………………………………...…………………………10

Economic Analysis: $15 per unit…………………………………………………..…………….11

What’s Next……………………………………………………………………..……………….11

Summary………………………………………………………………………...……………….11

References…………………………………………………………………………………….….12

Figures………………………………………………………………………………...………….15

Appendix……...……………………………………………………………………………...…..23

Project Schedule………………………………………………………….………………23

Team Contract……………………………………………………………………………24

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Introduction ___________________________________

Doctor’s Supply Inc. approached Grizzly Design with the task of researching and designing a

more reliable and easier to use smart device to measure joint range of motion in physical joint

therapy. The team was asked to consider an electronic recording device, mounting fixtures, a

patient-readable scale, and the ability to monitor the force applied to the joint [1]. The main area

of focus is on the elbow but the device should be easily adapted to fit other joints as well. The

biggest constraints on the device are accuracy, reliability, and the production cost [1]. Grizzly

Design’s goal is to produce a device that incorporates all of the client’s needs into one simple

and easy to use device.

Grizzly Design developed a user friendly smart gyroscope device with the capability of

automatically recording measurements while still being very accurate and reliable. After

thorough research on the topic, the team has developed a compact final design that will meet all

of Doctor Supply Inc.’s considerations. The final design incorporates a gyroscope to measure

joint range of motion as depicted in Figure 0 (a more detailed collection of figures can be found

in the Graphics Portfolio). The use of a gyroscope makes Grizzly Design’s device more reliable,

accurate and faster than currently used devices. Patients will also be able to automatically record

angle measurements to a nearby computer to check individual progress without the help of a

therapist. Incorporating a gyroscope to measure the joint range of motion allows for a compact

and customizable final design. The device can be fit to any size and can be used for more than

just the elbow. These considerations by Grizzly Design will make their device easily marketed in

the health industry.

This report will begin by discussing Alternate Designs that were considered in the early phases

of the design process. This is followed by a detailed description of the Final Design including

the four main subsystems: Electronics and Software, Housing and Mounting, Force, and

Instruction Manuals. It concludes with a operation and maintenance instructions followed by the

details of the cost estimate and the figures referenced throughout the report.

Alternative Designs___________________________________

External Frame Goniometer Brace The first design proposed was based on current goniometers and elbow braces. The brace can be

consistently attached to a patient’s arm in line with the correct landmark points used for joint

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range of motion measurement using calibrated hardware and straps. A digital protractor attached

to the brace would also line up with the landmark points, allowing for consistent measurements

from patient to patient and consistency between multiple measurements on the same patient. See

Figure 1. This design was not much different from the current goniometers, but it took away the

potential for error in lining up the goniometer to the patient’s landmark points on their arm. The

digital protractor is also much more accurate and precise than the current basic goniometers in

use. This design was eliminated because of its bulkiness, unoriginality, and difficulty to

universalize to any size patient.

Simplified Motion Capture using Infrared Mapping Another alternative considered was an infrared motion mapping system to measure the range of

motion of a joint. Infrared markers would be placed like stickers on each of the landmark point,

and on the actual joint itself, and a camera would track the motion of the three points relative to

each other. See Figure 2. Software would determine an angle of movement from that tracking

data, which would be the final reading delivered to the patient [2]. As long as the motion was in

the same plane, and the markers were attached properly, this would be a very accurate system,

but it would be expensive relative to the other designs, much more complex, harder to use alone

or at home, and there could be inaccuracies in attaching the markers [3]. See Figure 3 for the

Decision Matrix used to quantify the advantages and disadvantages of these designs.

Final Design_________________________________________

Gyroscope The final design was picked for its advantages of compactness; accuracy; precision between

readings, patients, and therapists; ease of use; customizability; and low cost. The client’s most

important requests for the new design are accuracy and precision, and the gyroscope is both very

accurate and precise [1]. The gyroscope was tested against a digital protractor, and proved to be

just as accurate in measuring the angle. The gyroscope, however, is much more compact and

customizable than the digital protractor. The electronics and their protective enclosure could

easily be as small as a wristwatch. See Figure 0. The patient can simply strap the device onto

their wrist, zero it when the arm is fully extended, and then move their arm to its full range of

motion, as the gyroscope measures the angle. The gyroscope measures accurately as long as the

upper arm does not move, and it requires nothing more than a small device strapped to the

patient’s wrist. The device has a USB cable connected to a computer where the data from the

gyroscope is interpreted by a program and gives the patient a large-font view of their joint’s

angle of rotation. Because the data is recorded to the computer, it can all be stored electronically

and can be easily sent to a therapist to interpret the results and track the patient’s progress. The

nature of the gyroscope makes it compact, lightweight, and easy to use. It is easy for the patient

to use without a therapist present, allowing a single therapist to service more patients. The

current goniometers need to be lined up to landmark points on the patient to get a proper reading,

but the gyroscope only needs to be securely attached to the patient’s wrist (so that it does not

move relative to the wrist during the test), just like a watch, in order to get accurate readings.

This removes a lot of the error in current goniometer measurements by using relative changes

rather than absolute angles (which produce the same reading). The gyroscope device is a very

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compact and easy to use design that does not sacrifice accuracy or precision, giving consistent

readings while being small enough to be comfortably worn and easily operated.

Electronics and Software ______________________________

Introduction This section outlines the details concerning the actual gyroscope, the processing unit, and the

software that makes the components work with very little user interaction. The actual gyroscope

itself and its necessary intermediate components are encased inside a sturdy and durable ABS

plastic box to protect it from the elements. This protected unit is attached to a watch-like brace

that connects it to the arm. See Figure 0. It starts with the overall layout and how the subsystem

fits in with the rest of the design and how it meets the client’s requirements. It then specifies the

details of the actual gyroscope, intermediate components, and software before concluding with

assembly information and testing results.

Overall Physical Subsystem Layout The gyroscope is connected to an analog-to-digital converter (ADC). The ADC is then

connected to a micro USB port that connects the computer to the device via a micro USB cable,

and the computer displays the angle of joint rotation. The entire system sits on a printed circuit

board (PCB) approximately the size of a wristwatch. See Figure 4.

Connections to Other Subsystems The PCB is glued to a watch band that straps onto the patient’s wrist. This entire system is

secured and enclosed inside a protective box that is attached to a brace that straps onto the lower

arm. See Figure 0.

How it Meets Client Requirements The electrical nature of the digital gyroscope is for accuracy and precision, which are the most

important aspects of this new range of motion device. Furthermore, the software is completely

automated and user-friendly so that the patient simply plugs the device into their computer and

does the test. This makes it extremely easy to use, another important client requirement [1].

The Gyroscope Unit How Gyroscopes Work

A gyroscope is simply a spinning wheel. Anything that spins has an angular momentum that

keeps it spinning in its current plane thus preserving the gyroscope’s orientation in space. This

resistance to a change in its orientation is called a Coriolis force [4]. Micro-electro-mechanical

(MEM) gyroscopes have been developed that use similar principles at a fraction of the size and

cost of the fully mechanical units. The digital gyroscope oscillates a small mass to produce the

displacement and when the gyroscope is rotated by an arm in physical joint therapy, there is a

Coriolis force that resists the initial displacement. Since the initial displacement is known, the

change can be measured as a capacitance difference that is then converted to an analog signal

that a computer can read [5].

Gyroscope Specifications

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The gyroscope is a relatively simple silicon chip with 10 solder points to connect it to the PCB.

It is the LPY503AL model from Karlsson Robotics. It has dual axis capabilities (it can measure

the rotation of two axes simultaneously) and runs off of 3.3 volts with a sensitivity of 8.3 mV/º/s.

It is approximately 5mm x 5mm x 1.5mm in length, width, and height and weighs effectively

nothing. It costs about $5 retail [6]. See Figure 0. There is a direct relationship between cost

and precision in these digital gyroscopes, and that optimal tradeoff can be customized to fit the

client’s needs.

PCB Specifications

The printed circuit board (PCB) is circular in shape and approximately 30mm in diameter. The

exact shape and size of the board is based on how exactly the electrical engineer designs the

board. This means that it requires an outside consultant for a one-time design of the PCB. But

once it is designed once, it can be mass produced very inexpensively [7][8].

The Analog-to-Digital Converter The Analog-to-Digital converter (ADC) converts the analog signals which are just a flow of

electrons from the gyroscope into a binary number that can be transmitted through the USB port

to the computer [9]. The computer then performs all the calculations and displays the current

angle of rotation in a large font on the screen.

ADC Specifications

The ADC is a simple silicon chip with 8 solder points to connect it to the PCB. It is the

MCP3002 model from Karlsson Robotics. It has a 10-bit converter, which is more than enough

to get the desired .01 degree level of accuracy. It runs at just under 1MHz and also requires

3.3V. It is approximately 18mm x 15mm x 6mm in length, width, and height and weighs

effectively nothing. It costs $2.30 retail [10].

USB Cable and Port Specifications The USB port simply transfers the binary numbers from the ADC to the computer. It is the

standard Micro USB port from Karlsson Robotics. It is 4.8mm x 9.8mm x 2.9mm in length,

width, and height and weighs effectively nothing. It retails for $1.50 [11]. The cable is a 6-foot

(once again the length is customizable) male-to-male Type A to Micro USB cable. It retails for

less than $0.50 at a variety of outlets [12].

Software The software is the heart of this design. It is fully customizable and adaptable to any of the

client’s or patients’ needs. The patient simply plugs the USB cable into their computer and the

software automatically loads the instruction slides and then the necessary user interface for the

patient to conduct the test. The patient then gets in position, presses the start button on the

computer, then goes through the motion and the angle is displayed in real time right in front of

them on the computer screen. The patient presses the stop button and the program then saves the

angle for patient records. Since the software is open source, there is no need to re-download any

programs or be connected to the internet in any way; after a one-time download, the computer

recognizes the device and automatically opens the correct software so the patient can conduct

their tests.

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Details of Programming

The program uses an Arduino user interface with the C programming language. The actual

program is fairly simple. Upon launching, the program enters a while loop that waits for the user

to press the start button. Once this happens, the first loop is broken, and the program enters a

series of short integration loops. Inside these short loops, the gyroscope sends the raw signals to

the computer (through the ADC and USB cable). The computer processes the signals and then

converts them to the correct units of degrees/second. To get the current angle, these values are

integrated with respect to time. Because each integration loop lasts 5 milliseconds, the angular

velocity measured at the beginning of each loop (at each 5 millisecond interval) is multiplied by

.005 seconds to get the change in angle. Then all the changes in angle are summed up to get the

current angle [13]. It’s not a perfect integration, but in reality, the angular velocity does not

change very much, if at all, in the 5 millisecond integration loop. Once again, faster, and more

expensive, hardware will be able to increase the accuracy, but this is a small gain that can be

decided on by the customer if desired [14].

Customizable and Optional Features of the Software

Voice activation in place of the start and/or stop buttons

Wireless connection to the computer (no USB cable needed)

Ability to hide results from patient

Progress chart that maps the range of motion versus the time since starting the treatment

Automatic result communication with the therapist (email results and/or progress chart)

Automatic notification via email, SMS, or other alarm alerting the patient when to

conduct the test

Live video feed with the therapist so the therapist can see the results real time

Anything else the client or patient may need

A Note about Customization One of the biggest attractions about this design is the ability to customize it perfectly for the

client’s needs. The software lends itself to being able to adapt to any of the client’s requests,

thus allowing customers to get exactly what they want. However, it is understandable that the

client will not have the answers to all these customizable features. For this reason, the standard

components are the pieces that appear to be the best based on the information received from the

client and detailed research about each component. However, it is important to have all these

features so that the client does not feel pressured into buying one, very specific design, but rather

one that they can make their own if they want to.

Assembly Everything within this subsystem is mass produced on a PCB assembly line in a factory.

Assembly costs are very low if not effectively zero assuming that at least several thousand of

them are made [8].

Testing Results A working prototype of the design underwent real-world testing and produced very encouraging

results. The gyroscope was mounted to an industry-standard digital protractor. The gyroscope

was rotated through the same angle five times and produced a relative standard deviation

6

matching that of the digital protractor (.13%). This means that the gyroscope is at least as

precise as the industry-standard digital protractor. Later, the device underwent a rotation of 90° using the board as a right angle and produced a standard deviation of less than half a degree.

This is ten times better than current goniometers which are considered precise with a standard

deviation of 5 degrees. This test still had human error associated with it as the sides of the board

are not perfectly flat, but it was conducted to see how it performed off of the digital protractor.

Finally, the device was run through real-world simulations of actual joint range of motion tests.

This produced a consistent standard deviation of slightly less than 3 degrees. Most of this error

comes from the fact that nobody can rotate their arm the exact same amount ten times in a row.

Furthermore, the device was not strapped to the wrist, so a significant part of that error came

from relative movement between the device and the wrist, which does not happen when it is

worn with the strap.

Summary A digital gyroscope measures and calculates the angle of rotation and then displays it on a

computer screen while meeting all of the client’s requirements [1]. The gyroscope and ADC are

kept in a protective box and is then attached to a watch-like brace that secures it to the arm.

There is a USB cable connecting it to the computer that displays the current angle of rotation.

See Figure 0. The gyroscope is extremely accurate and precise and the software is explicitly

designed for ease of use. Experimental results proved promising and showed that the gyroscope

is at least as precise as industry-standard digital protractors. The software is fully customizable

and designed with patient ease of use in mind. There is a direct relationship between precision

and cost of the electronic components, which can be customized based on client’s needs. This

shows an important aspect of this design. It is fully customizable (or fully uncustomizable and

everywhere in between) to whatever the client wants or needs. Finally, this subsystem is mass

produced in a factory making assembly cost negligible (assuming high quantity). Total cost for

this system is estimated to be less than $10 retail.

Housing and Mounting ______________________________

Introduction This section details the protective housing for the gyroscope and its related electronic

components as well as the strap system used to attach the housing to the patient. It begins with

the protective housing for the electronics and explaining how it meets client’s requirements

before detailing the exact structure and how it fits into the other systems. It then moves on to

detailing the wrist strap and the assembly process.

Housing The gyroscope housing needs to be made out of a durable, lightweight material that is non-

conductive to avoid possible damage to the electronics; it should be as inexpensive as possible

while maintaining good structural durability. It needs to be stiff and able to be easily cleaned by

common chemicals and machines. The materials that were considered were: ABS plastic,

Aircraft Aluminum, and PVC plastic. The Aircraft Aluminum was more expensive than the

plastics and is much more conductive than the plastics. The PVC was inexpensive, but it was too

7

soft and did not have the required durability and was sensitive to chemicals and light [15].

Therefore, it was determined that ABS is the best material.

The housing is made of ABS plastic; ABS is very durable, costs only about $0.30/lb., is easily

formed into the necessary shapes, is non-conductive, resistant to chemicals, and is durable

enough to withstand continued use [16][17]. ABS has a flexural modulus of 300,000 psi [18] so

it resists deformation more than sufficiently for normal use. The client wanted a unit that was

durable enough to last for many uses, could be inexpensively produced for large scale

distribution, and could be used for a variety of patient sizes; therefore ABS is ideal for the

client’s specifications [1][15].

The Housing consists of a small circular back plate with two holes in it to secure the circuit

board and the back plate to the rest of the housing, and a cylindrical housing shell for the

electronics that has a small hole in it to accommodate the micro USB cable. The bolts used to

secure the housing together are carriage bolts to reduce any discomfort on the patient from the

bolts. See Figure 6.

The gyroscope housing and back plate consists of pieces of 2mm thick ABS plastic sheeting to

make a cylindrical shell around it with a rectangular whole open in one side for the computer

plug in. The bolts should be stainless steel to resist corrosion and possible allergic reactions of

the patients that could arise from the use of other metals.

Wrist Strap The wrist mounting system needs to be lightweight, flexible, easily cleaned, durable, and

comfortable for the patient. The best material would be some form of cloth or flexible plastic.

Materials that were considered were: nylon cloth, rubber, silicon, PVC, high-density

polyethylene (HDPE), and aircraft aluminum. Nylon was dismissed because it is not easily

cleaned between patients [19]. Silicon and PVC were both not durable enough to withstand

repeated use. Aluminum was also dismissed because it is considerably more expensive,

potentially difficult to adjust to different patients, and less comfortable. Rubber is more

expensive than HDPE and is less resistant to wear [20]. Therefore, HDPE is the optimal material

for the wrist strap, since it is durable, inexpensive at only about $0.65/lbs., easy to clean,

flexible, and relatively lightweight [21]. It is fashioned with a buckle system to secure it to

different sized wrists easily. See Figure 7.

Assembly The gyroscope housing is attached to the wrist strap by spring pins similar to that of a common

wrist watch. The electronics unit is attached to the protective housing by two carriage bolts. The

PCB has the carriage bolts running through it to the top of the housing to secure the electronics

unit inside the protective housing. See Figure 6. Assembly costs are approximately $3 due to

the tedious task of preparing and assembling the plastic and attaching the wrist strap.

Summary The housing and mounting system consists of 3 main pieces, the electronics unit, the protective

housing unit, and the wrist strap. The housing is constructed of ABS plastic. The electronics unit

is secured inside the protective housing by two carriage bolts. The housing is secured to the

8

wrist brace by a set of spring pins. See Figure 6. The wrist strap is made of HDPE with a buckle

system to secure it to a wide variety of patients (see Figure 7). The total estimated cost for this

system is less than $5.

Force System ______________________________

Dumbbell To apply a consistent force on the patient to ensure that there are no inconsistencies in the

readings caused by differing amounts of applied force, the patient will hold a known weight like

a dumbbell [1] in their hand. The exact amount of weight will be determined by the therapist but

will otherwise remain constant during therapy. To apply this force the patient will lay with their

back parallel to the ground and their arm to their side with the weight in their hand. The patient

will then raise their arm and bring it past the 90 degree point and then relax their arm so that the

weight will apply a constant force to the joint to assist in its bending. Since the weight will be

constant and no force from the patient or the therapist is used then the force applied will be

consistent for all readings during therapy. This system also does not require the therapist

presence to take readings, allowing for therapists to service a much greater number of patients

and for patients to take more readings to get a more reliable data set [1]. Assuming the therapist

or the patient has a dumbbell or other known weight, the cost of this system is zero.

Optional Constant-Tension Spring (used only in certain circumstances) Another way of providing a constant and consistent force on the joint is to connect the lower

moveable part of the joint with the stationary upper part via a constant tension spring. Constant

tension springs provide the same amount of force no matter the extent of the spring extension.

They are the same springs used in tape measurers. They wind up into a convenient little cylinder

less than a cubic inch in volume. The solution is to attach it to the wrist mount, and to another

mount on the patient’s shoulder (see Figure 8). The wrist mount is simply a bolt that the spring

rests on as shown in Figures 9 and 10. This would apply a constant force to the joint, eliminating

the need for a therapist to apply a force and guess at whether or not it was actually constant or

consistent across different measurements. The spring used is from McMaster-Carr. It is

19.05mm in diameter and 12.7mm in width and can extend to 66cm in length (which is well

beyond the length of any arm). It provides a constant force of 7.2 newtons and retails for about

$10 [22]. The spring system does have a few safety and design concerns, which is why it is

optional. First, it is difficult to take off quickly should the patient reinjure the joint. Second, it is

bulky and almost doubles the cost of the device. However, it does not require the patient to lay

parallel to the floor, so a patient who has difficulty lying down can do the exercises against a

wall. It is also more accurate in providing a constant force all the way through the exercise.

Instruction Manual ______________________________

Introduction The instruction manual will serve as an overall comprehensive guideline for users on how each

component should be used to attain proper data. It will also contain troubleshooting information

and also regulatory code compliance information for each subsystem. The instruction manual is

9

divided into two components, namely the paper-based instruction manual and the computer-

based user interactive instruction and troubleshooting manual.

Paper-Based Instruction Manual The instruction manual is a medium for Grizzly Design to communicate the operating principal

of the gyroscope device to potential users in a simplified manner. The instruction manual will

consist of two main components; the paper-based manual (see Figure 11) and the computer-

based user interactive instructions (see Figures 12 and 13). It will contain assembly, usage,

maintenance, and safety precautionary information for all components of the device. The initial

instruction manual will be compiled in English with the assumption that potential users can read

and understand the English language. However, translated versions of the instruction manual can

be printed if deemed necessary in the future.

The following are the main components of the paper based instruction manual, arranged in order

of priority, along with a detailed description of what it entails:

Safety Instructions

This includes all safety precautions and warnings against unsafe actions concerning the

gyroscope and force system. This section is necessary to protect the safety of the patients and for

potential liability reasons as accidents may occur [23].

Product Diagram & Assembly Instructions

This section pertains to the assembly of the Gyroscope since it is a multiple-piece based product.

This section contains labeled pictorial instructions so users can easily visualize the assembly and

mounting process [24].

Software Installation/Requirements

This section is linked to the electronics and software subsystem. This section contains the initial

software installation setup for the gyroscope as well as software requirements such as a list of

supported computer operating systems. Users require this information in order to ensure their

computers are capable of installing the necessary software.

Quick Start Guide

This section contains a step by step guide to begin using the gyroscope device. Users read this on

their computer after having performed the software installation.

-Refer to the computer based user interactive instructions below.

Troubleshooting

This section contains information necessary for software, hardware or physical component

troubleshooting. It contains a logical and systematic set of guides for the user to first identify the

source of the problem and the corresponding solution to the problem. The information here is a

compilation of most likely error that could surface from other subsystem, and its solution.

Regulatory Code of Compliance

This section lists all compliance codes and standards to which the gyroscope device adheres to.

These codes are generally those from the International Standard of Organizations (ISO) and the

10

American National Standards Institutes (ANSI). A list of code of compliance is necessary since

the gyroscope is an electronic device. Potential users have the right to know that this electronic

device complies with all required standards. It reassures users that the device is safe to use.

Technical Specifications & Maintenance

This section contains all technical data regarding the device such as the type of electronic

component along with relevant model numbers. It also contains power, voltage, and current

information. The maintenance section provides simple maintenance procedures to ensure the

device is always in a proper working condition.

Warranty and Customer Support

The final section contains warranty and customer support contact information in case the device

needs repair or part replacement.

The physical manual itself is designed to maximize user readability and comprehension. It is in a

booklet form, printed on paper. See Figure 11. It has a high text-to-background contrast, which is

accomplished best with the colors black and white. The same font type and page layout are used

throughout the manual to avoid confusion. Varying font sizes are used to denote importance. The

text and images are arranged such that there is ample white space surrounding them. This is to

prevent the user from feeling overwhelmed with information [25].

Computer Based User Interactive Instructions

Upon the initial setup, the user is prompted on the computer with a set of simple quick guide

steps to start using the device as depicted in Figure 12. The instructions here are pictorial and

animation based so as to make the operating principle as interactive and visual as possible. See

Figure 13. The interactive aspect allows the software to immediately detect any user based error

and prompt the user to make amends before proceeding to the next step as depicted in Figure 14.

Summary Overall, the instruction manual consists of two components, the paper based instruction manual

and the computer based user interactive instructions. Both components must be used jointly in

order to fully understand and successfully attain data from the gyroscope.

Operation and Maintenance ________________________

Operation One of the biggest advantages of the gyroscope design is that it is extremely easy to use. There

is a simple 4-step process that the patient follows to conduct their test effectively. First, the

patient straps on the device to their arm like a watch. Second, the patient fully extends the arm

keeping the upper arm still throughout the entire exercise. Third, the patient presses the start

button and begins the exercise. Fourth, the patient relaxes the arm after the 90 degree point and

lets the gravitational force pull the arm to the completion of the test.

Maintenance

11

The device is very stable and durable. The parts should only be damaged in the most violent of

situations. Patients can refer to the instruction manual for part replacement information. In

general, the device should be able to withstand above normal usage. For software issues,

patients can refer to the troubleshooting section of the instruction manual.

Economic Analysis: $15 per unit________________________

One of the main attractions of the gyroscope design is its low production cost. The materials

(electronic components, plastic, and watch strap) retail for about $11. This means that buying in

bulk and directly from the manufacturer will save around 10%-20%. The software and

instruction manual require a one-time consultant to professionally design it and work out all the

flaws. This cost per unit becomes only a few cents (for paper and ink) after several thousand

units are produced. Likewise, the PCB requires a one-time consultant to professionally design

the circuit board, but the cost per unit also becomes very small (less than $0.50) assuming

several thousand units are produced. Again, the electronics are assembled on the PCB in an

assembly line factory where the cost per unit is effectively nothing [8]. The production cost of

the housing unit is no more than $4 putting the entire device at about $15 per unit (see Figure

15). This is remarkably inexpensive for such an accurate and precise device that is also compact

and easy to use (see Figure 15).

What’s Next? ___________________________________

The gyroscope device is a very exciting and innovative design that will change the medical

world. Even so, Grizzly Design is still fully invested and committed in the device’s continual

progression and advancement. For example, the team, given the chance, would like to adapt the

device to all joints including multi-dimensional ones like hips, wrists, ankles, and fingers.

Furthermore, Grizzly Design would like to bring this technology into other professions like

sports training where angles of rotation of the arm would be useful to know while doing bicep

curls, for example. The possibilities are nearly endless and Grizzly Design looks forward to

working with Doctor’s Supply Inc. in developing this design and using it to help change the

world.

Summary ___________________________________

Grizzly Design is confident that their design is the best device to fulfill Doctor Supply Inc.’s

need for a new range of motion device. The new smart gyroscope has several advantages over

current devices. The design is compact and simply attaches to the wrist, which allows for

versatility between patients and limbs. From therapist to therapist, patient to patient, and reading

to reading the gyroscope is the most precise angle measurement device on the market (less than

half of a degree of deviation in preliminary testing) while still being cost effective. The device is

extremely simple to use and the display is patient readable, so a therapist is not necessary all the

time allowing each therapist to see more patients. Above all, the new device will give the best,

most accurate data set possible for joint range of motion [1].

12

Current joint measurement devices, such as goniometers, are not effective enough for current

physical therapy. They depend on therapists’ subjective judgment to read the measurement on a

protractor. There is a significant problem with accuracy and precision dealing with different

therapists, patients, and readings. Currently, a therapist is necessary to take the measurement,

and readings from different therapists cannot be compared because each therapist may read a

goniometer slightly different. Grizzly Design’s new smart device is able to fix all of these

problems while still remaining inexpensive. The cost estimate for the new device is around $15.

This price is slightly more than current goniometers, priced around$3-$10, but the accuracy,

durability, and customizability make the gyroscope device worth the extra cost. In fact, in

preliminary testing, the device matched the deviation in industry standard digital protractors that

can cost at least twice as much. The last consideration Grizzly Design solved was the ability to

measure force applied to the limb. The team decided to use standard weight, such as a dumbbell,

to keep a constant force contracting the limb. The weight will be completely optional and will

not be used by all patients. For more detailed information on all aspects of the design, a

collection of graphics, figures, and drawings can be found in the Graphics Portfolio.

Some of Grizzly Design’s alternate designs include an external frame goniometer brace that was

unoriginal, bulky, and less accurate. The team also worked on a simplified motion capture

device that used infrared and camera sensors to detect the range of motion. It was too complex,

difficult to use, and only accurate in certain circumstances. Fixing all these problems, the final

design is very accurate and reliable, compact, inexpensive, versatile (it can be adapted to any

limb on any patient and can be customized to fit the patient’s exact needs), and easy to use.

Grizzly Design is confident their design will greatly increase the efficiency of joint range of

motion devices. With the final design, all of Doctor Supply Inc.’s requirements have been

resolved in a simple compact device. The final design was chosen because it is accurate, precise

between patients and therapists, easy to use, and will be easily marketed. Grizzly Design is

excited and confident of their final design and hopes Doctor Supply Inc. is as well. If there are

any questions, Grizzly Design can be contacted through Joe Meyer at jomeyer@mines.edu.

Thank you for choosing this team to help improve Doctor Supply Inc.’s product.

References ___________________________________

[1] B. Brunelle and R. Bach, “Smart Goniometer for Joint Physical Therapy,” Doctor’s Supply

Inc., Colorado Springs, CO, Colorado School of Mines, Jan. 2013.

[2] "Computing Research Association Distributed Mentor Project," Real-time Motion Capture,

Feb. 2013. [Online]. Available:

http://http://www.cs.utah.edu/~halzahaw/MotionCapture_main.html. [Accessed Feb. 24, 2013].

[3] “Occam Robotics,” Impulse Motion Capture, 2013. [Online]. Available:

http://www.occamrobotics.com/wp/?page_id=88. [Accessed Apr. 24, 2013].

[4] Gabriel Gache, "Softpedia," How do Gyroscopes Work?, Feb. 2008. [Online]. Available:

http://news.softpedia.com/news/How-do-Gyroscopes-Work-77809.shtml. [Accessed Mar. 17,

2013].

13

[5] J.E. Esfandyari, J.E. De Nuccio & J.E. Xu, "Solid Stats Technology: Insights for Electronics

Manufacturing," Introduction to Mems Gyroscopes, Nov. 2010. [Online]. Available:

http://www.electroiq.com/articles/stm/2010/11/introduction-to-mems-gyroscopes.html.

[Accessed Mar. 17, 2013].

[6] “Karlsson Robotics,” Dual Axis Gyro - LPR503AL - 30?/s, Mar. 2013. [Online]. Available:

https://www.karlssonrobotics.com/shop/dual-axis-gyro-lpr503al-30s/. [Accessed Mar. 28, 2013].

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pcb.htm. [Accessed Apr. 24, 2013].

[8] “Bittele,” PCB Quote Online, Apr. 2013. [Online]. Available: http://www.bittele.com/pcb-

quote-

online_T.asp?total=38,378.75&a24=4&c5=100000&c7=3&e7=1&c9=0.031&c11=2&c13=1&c1

5=Green&c17=1&c19=1. [Accessed Apr. 24, 2013].

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http://www.analog.com/en/analog-to-digital-converters/products/index.html. [Accessed Apr. 24,

2013].

[10] “Karlsson Robotics,” Analog to Digital Converter - MCP3002, Mar. 2013. [Online].

Available: https://www.karlssonrobotics.com/shop/analog-to-digital-converter-mcp3002/.

[Accessed Mar. 28, 2013].

[11] “Karlsson Robotics,” USB micro USB SMD Connector, Mar. 2013. [Online]. Available:

https://www.karlssonrobotics.com/shop/usb-micro-usb-smd-connector/. [Accessed Mar. 28,

2013].

[12] “MonoPrice,” 6ft USB 2.0 A Male to Micro 5pin Male 28/28AWG Cable, Mar. 2013.

[Online]. Available:

http://www.monoprice.com/products/product.asp?seq=1&format=2&p_id=4868&CAWELAID=

1329450556&catargetid=320013720000010917&cagpspn=pla&gclid=COOptN_G5rYCFck-

MgodehUAVw. [Accessed Mar. 28, 2013].

[13] “Arduino,” Guide to gyro and accelerometer with Arduino including Kalman filtering, Apr.

2011. [Online]. Available: http://arduino.cc/forum/index.php?topic=58048.0. [Accessed Feb. 24,

2013].

[14] “Hobby Electronics,” Accelerometer and Gyro Integration, 2013. [Online]. Available:

http://www.hobbytronics.co.uk/accelerometer-gyro. [Accessed Apr. 24, 2013].

[15] “Diffen,” ABS vs PVC. [Online]. Available:

http://www.diffen.com/difference/ABS_vs_PVC. [Accessed Apr. 24, 2013].

14

[16] “UL IDES.” Resin Material Prices: Secondary Markets, 2013. [Online]. Available:

http://www.ides.com. [Accessed Mar. 18, 2013].

[17] “MakerBot,” What’s the cost of printing with a MakerBot. [Online]. Available:

http://makerblock.com/2010/08/whats-the-cost-of-printing-with-a-makerbot/. [Accessed Apr. 24,

2013].

[18] “TAP Plastics,” ABS Extruded Sheet • High Impact ABS (Acrylonitrile-Butadiene- Styrene)

Technical Data, 2013. [Online]. Available: http://www.tapplastics.com. [Accessed Mar. 17,

2013].

[19] “Brunson,” HDPE Versus Nylon. [Online]. Available:

http://www.brunsonnet.com/index.cfm?fuseaction=page.display&page_id=47. [Accessed Apr.

24, 2013].

[20] “Arihant Gold Plast,” Products. [Online]. Available:

http://www.plastemart.com/upload/home/plastic-sheets-ABS-arihant.asp. [Accessed Apr. 24,

2013].

[21] “Stress Engineering Services,” Resin Prices, Dec. 2009. [Online]. Available:

http://www.stress.com/BMQtrly.php?pid=342. [Accessed Apr. 24, 2013].

[22] “McMaster-Carr,” Constant-Force Springs, 2013. [Online]. Available:

http://www.mcmaster.com/#constant-force-springs/=mgue1e. [Accessed Mar. 6, 2013].

[23] L. Guren. “Writers UA,” Ten Tips for Tasks: Best Practices for Writing Effective

Procedures and Instruction Sets, 2011. [Online]. Available:

http://www.writersua.com/articles/tentips/. [Accessed Mar. 19, 2013].

[24] A. Gregory. “Sitepoint,” 7 Tips for Writing an Effective Instruction Manual, Mar. 16, 2010.

[Online]. Available: http://www.sitepoint.com/7-tips-for-writing-an-effective-instruction-

manual/. [Accessed Mar. 18, 2013].

[25] Dr. P. Hodgson. “UserFocus,” Tips for writing user manuals, June 4, 2007. [Online].

Available: http://www.userfocus.co.uk/articles/usermanuals.html#Anchor-How-14210.

[Accessed Mar. 20, 2013].

15

Figures ___________________________________

Figure 0: Compact Gyroscope (Final Design)

Figure 1: External Frame Goniometer Brace (Alternate Design)

Strap

Electronics

Housing

USB port

16

Figure 2: Simplified Motion Capture using Infrared Mapping(Alternate Design)

Figure 3: Decision Matrix

17

Figure 4: Electronics

Figure 5: Preliminary Testing Results

Trial Angle (90) Trial Angle Trial Angle

1 90.55 1 125.52 1 128.08

2 90.01 2 131.29 2 131.24

3 90.23 3 131.05 3 132.78

4 90.25 4 125.07 4 128.07

5 90.46 5 127.98 5 134.05

6 89.71 6 122.08 6 135.4

7 91.3 7 124.76 7 133.42

8 90 8 127.8 8 135.89

9 90.31 9 125.63 9 135.24

10 90.07 10 130.01 10 131.23

Average 90.289 Average 127.119 Average 132.54

Std. Dev. 0.430696 Std.

Dev. 2.869524 Std. Dev. 2.703383

PCB

ADC

PCB

Gyroscope

USB port

18

Figure 6: Protective Housing

Figure 7: Wrist Strap (adjustment buckle not shown)

USB port

Carriage Bolts

Strap Spring Pins

Diameter: 50.8mm

19

Figure 8: Optional Spring Shoulder/Upper Arm Connection System (Simplfied)

Figure 9: Housing with Optional Spring Holder

Figure 10: Entire Device with Optional Spring

Constant Tension Spring

Shoulder Strap

20

Figure 11: Paper-Based Instruction Manual

21

Figure 12: The Computer Based User Interactive Instructions

Figure 13: Quick Start Guide- Calibration Message

Picture based

instructions to

make

instructions as

visual as

possible.

22

Figure 14: Immediate Error Message Prompt

Figure 15: Exploded View with Cost Information

Gyroscope ($5)

USB port

($1.50)

Gyroscope

Gyroscope

ADC

($2.30)

PCB

($0.40) Housing

($0.10)

Housing

($0.10)

Wrist Strap

($0.50)

Carriage Bolts

($0.10)

23

Appendix ___________________________________

Project Schedule

24

Team Contract

Grizzly Designs hereby declares a team contract to develop a professional system of

accountability for and understanding of expected behaviors while working in the team

environment.

Grizzly Designs paramount objective is to develop a revolutionary range-of-motion device for

Doctor’s Supply Inc. that meets all of the client’s needs as detailed in their letter to us. Grizzly

Designs also strives for all work to be completed and submitted on time and in a professional,

organized, and intelligent manner.

Team members should try to respectfully convey ideas and/or opinions.

For disagreements the team will vote, the majority decision will be upheld by the whole team.

Team members will be responsible for completing their assigned tasks on time.

Team members will not submit any important documents without first submitting them to

another team member for review.

All team members need to be functional and productive at all team meetings and team time.

If you cannot make a scheduled meeting time or due date inform any concerned parties as far in

advance as possible.

All projects should be completed as early as possible with a minimum of 24 hours prior to due

date.

All expenditures will be prior approved by the whole team and will be evenly divided. Any

disagreements will be decided by a majority vote. Any expenditure spent without the approval of

the team will be the responsibility of the involved parties.

If a team member has any grievances they will be brought up and addressed as needed.

These signatures represent the promise of the team members to uphold the terms of this contract

to the fullest extent of their ability and their understanding of the potential consequences for their

actions or their inability to honor this commitment.

Quinn Wolf Tyler Rockley Loren Awalt Deavin Dev Joe Meyer