P11011: MOTION-TRACKING SYSTEMDETAILED DESIGN REVIEWBrittany BochetteLindsey ClarkMike OstertagMaya RamaswamyAndrei Stihi

AGENDA• Project Background• Knee Flexion System

– Updated Customer Needs– Updated Engineering Specs– Sensor and Attachment Choices– Test Plans

• Head Tilt System– Updated Customer Needs– Updated Engineering Specs– Sensor and Attachment Choices– Test Plans

• Project Budget• Risks• Project Plan• Questions for Audience

PROJECT BACKGROUND Motion-tracking system that measures knee

flexion and head-tilt Continuation of past senior design groups

P10010 Sensors P10011 Attachment Methods

Customers are Nazareth Physical Therapy Clinic and Rochester General Hospital

KNEE FLEXION Clinicians and students work with patients

recovering from strokes

Goal is to see improvement in flexion

Sessions are short

Measuring is done by goniometers

UPDATED CUSTOMER NEEDS

Sanitation

Cost

UPDATED ENGINEERING SPECSTwo new engineering specs were added to address issues of the device needing to be sanitizable, as well as not impeding patients by its size.

-The final device will need to either be wipe able, or have removable sleeves that can be washed about once a week.

-The outwards size of the device will need to be minimized so that patients are not impeded or hit the device against something.

SENSOR SELECTION CRITERIA Cost Ease of Use Durability Precision Ease of Attachment to the Rest of the System Size – To Fit Into Attachment Method (Low

Profile)

BENDSHORT FLEX SENSOR

Pros:•Size •Ease of Use

Cons:•Cost•Durability•Precision•Ease of Attachment

INCLINOMETER

Durability Precision Size

Cons:

Pros:

• Cost• Ease of Use• Ease of Attachment

HONEYWELL 785-381L25K POTENTIOMETER

Pros: Cost Ease of Use Precision Ease of Attachment Size

Cons: Durability

BI TECHNOLOGIES POTENTIOMETER

Pros: Ease of Use Durability Precision Ease of Attachment

Cons: Cost Size

HONEYWELL 785-380C3100K POTENTIOMETER (Used as Baseline)

Cost Ease of Use Durability Precision Ease of Attachment

Pros:

Cons: Size

DETAILED SCHEMATIC

ATTACHMENT SELECTION Utilizing the potentiometer sensor, two

arms need to extend from either side of it to measure knee flexion.

Slide a neoprene sleeve up the leg with the device attached to the outside of it.

Typical knee brace with Velcro straps around the upper and lower legs.

Wrapping leg in Ace bandages.

ATTACHMENT SCHEMATIC

Designed to be incorporated into existing knee braces

TEST PLANS Included in packet

Based heavily off of last years test plans (same needs apply for most part)

Includes impact testing on enclosure and maximum torque required to impede motion

HEAD TILT Studying movement of patients with cervical

dystonia

Primarily a research setting

Goal is to see accurate measurement of several movements

Measuring is done by goniometers

UPDATED CUSTOMER NEEDS

Sanitation

Ability to walk around while using the device

UPDATED ENGINEERING SPECS Ability to measure shift of head

Measured in centimeters

Ability to measure while walking Measured as error to expected value

Ability to be sterilized Materials must be able to be cleaned by alcohol

wipes Examination for level of sterilization, not required

SENSOR SELECTION CRITERIA

Cost

Ease of Use

Weight/Size

SENSOR SELECTION

Atomic IMULarge form factor6 degrees of freedomExpensive

Razor Ultra-ThinNo on-board regulation6 degrees of freedom

AccelerometerCan’t measure all directionsNo on-board regulationVery inexpensiveLarge form factor

SENSOR SELECTION

Razor IMU9 degrees of freedomSingle, flat boardOn-board microcontroller

DETAILED SCHEMATIC

SCHEMATIC

ATTACHMENT SELECTION Utilizing the 9DOF sensor, it needs to be

securely held to the top of the head. A second sensor will need to be fastened to the body.

Baseball cap with the sensor box placed on top. Headlamp style strap. Wrestling style head strap.

The body sensor will need to be securely held to the upper chest or back.

ATTACHMENT SCHEMATIC

A head strap will be custom sewn from existing headlamp style straps, with an electronics enclosure box on top housing the sensor package.

TEST PLANSIncluded in packet

Will be based largely off last year’s teams testing methods.

Both the enclosure and the sensor itself have a list of tests to be performed

CONNECTION INTERFACE Arduino Pro Mini (5V) was selected for the

following reasons: Programmable configurations Future expandability Ease of Use Size Cost

http://www.sparkfun.com/commerce/product_info.php?products_id=9218

INTERFACE AGREEMENT Selected USB as top choice

Speed Signal Integrity Universal use

Personal Healthcare USB Device Standardizes protocol for personal healthcare

devices

http://www.tomsguide.com/us/pictures-story/12-USB-peripherals-accessories.html

SCHEMATIC

PROJECT BUDGET

RISK MANAGEMENT UPDATES

PROJECT PLAN UPDATES Updates to the work breakdown structure Critical path:

1. Research sensors2. Select sensors3. Research attachments4. Select attachments5. Design detailed schematics6. Finalize design

QUESTIONS FDA approval? Following standards? How do you think the attachment methods

can be improved? Are the test methods adequate?