FEBRUARY 15 T H , 2013RIT MSDI
Detailed Design ReviewP13265 Motorcycle Safety Light Backpack System
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MSD Team
Primary Customers: Sport bike/standard riders who ride with backpacks
Surrogate Customers: Aaron League Andrew Nauss
Faculty Guides: Leo Farnand Vince Burolla
Industrial Design Consultant: Killian Castner
Team Members: Mike Baer, Project Manager Tyler Davis, Lead Engineer Ben Shelkey, ME Project Engineer TJ Binotto, EE Project Engineer Eric Dixon, EE Project Engineer
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Today’s Agenda
I. Overview 5 minutes, 1 slide
I. Project Description RecapII. Borrowed Motorcycle Specs
II. System Model Design 50 minutes, x slides
I. Family Tree, System OverviewII. System ComponentsIII. CAD Models/DrawingsIV. Component Assembly PlansV. Schematics, Pseudo-CodeVI. Bill of Materials
III. Feasibility Analysis, Prototyping, and Experimentation 30 mins, x slides
I. Testing for critical componentsIV. Test Plans 5 mins, x
slidesV. Next Steps 15 mins, x
slidesI. Updated Risk AssessmentII. MSDII Plan
VI. Conclusion, Comments 15 mins, x slides
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I. OVERVIEW
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Project Description Review
This project is intended to be prototype stage for marketable product for motorcyclists: Two major needs identified by motorcyclists:
1. Safety Hurt Report
Motorcyclist safety study performed by Henry Hurt, published in 1981 Of the accidents analyzed, ~75% of motorcycle accidents involved collision with
another vehicle “Failure of motorists to detect and recognize motorcycles in traffic is the
predominating cause of motorcycle accidents” Motorcycle Conspicuity Study
Riders wearing any reflective or fluorescent clothing had a 37% lower risk than other riders
Conclusion: “Increasing the use of reflective or fluorescent clothing, white or light coloured helmets, and daytime headlights…could considerably reduce motorcycle crash related injury and death.”
2. Electronics charging Most motorcyclists have no means of charging electronics
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Project Description Review
Conducted market survey regarding safety equipment and small electronics charging Currently at 77 participants (for results visit EDGE website)
Summary of target market (motorcyclists who): Often or always wear backpacks
Carry bulky items, such as books or laptops Ride in 4 seasons, and wet conditions (rain, fog, snow) Currently do not have method for charging electronics (such as
cell phone) Micro USB charging connection required
Believe visibility is important Utilize reflective surfaces, bright colors, and lighting systems
Would consider upgrading their existing lights to LED lights Place importance of aesthetics and durability of products
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Updated Engineering Specs
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Updated Engineering Specs
9Borrowed Motorcycle
• Type: 2006 Kawasaki Vulcan EN500• Owner: Andrew Nauss, 5th year ME
• Gave permission to test on bike and make small modifications, if necessary
• Not ideal type of bike for target market, but it shares same engine and electronics with the Ninja 500, a popular entry-level sport bike
Vulcan EN500
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II. SYSTEM MODEL DESIGN
Physical System OverviewBackpack
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Electronics Box Inside Bottom Backpack Compartment
Turn Signals
Brake/Running Lights
System Power Switch
Motorcycle Power Connector
User Control Panel On Chest Strap
Ambient Light Sensor
Physical System OverviewMotorcycle
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Transmitter Box
(Inside Box)Transmitter Board
w/ Xbee Transmitter
Bike Power In
Bike Light Signals In
Power Out
Wireless Light-Signals Out
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Family Tree (1/3)
Continued
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Family Tree (2/3)
From Backpack Assembly
Continued
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Family Tree (3/3)
From Backpack Assembly
Backpack Shell16
Shell Drawing
Shell Back
Shell Front
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Backpack Assembly
Shell
Cut and assemble main compartment zipper to length. Apply Liquid Nails to inside edges of top shell Attach and clamp fully zipped zipper to shell following the
instructions of the Liquid Nails Wait for glue to fully cure Safety pin unglued zipper side to soft backpack back Unzip zipper Sew second half of zipper to soft back Cut and assemble bottom compartment zipper to length Apply Liquid Nails to one connection corner of both shell halves Attach only the starting section the zipper following 3-4 Attach the rest of the zipper using non-permanent method. Using a paintmarker or sharpie make marks on shell/zipper in 1in
increments (these will be used to make sure zipper and shell are lined up properly when adhering).
Unzip sections Remove zipper from both sections and clean off non-permanent
adhesive Attach zippers halves to each shell section separately following 2-4. Unzip Apply Liquid Nails to back edge of bottom shell section. Attach and clamp bottom fabric backpack flap to back edge of shell
following 3-4. Attach quick access panel following 9-18.
LEDs
Drill Wire holes in all light strip slots. Place LED light strips in their appropriate slots with proper adhesive. For each light signal slot line lens ridge with silicone sealer. Press each lens into their appropriate slot. Wipe off any excess sealer and allow to dry
Electronics Pouch, Easy Access Pouch and Other
Place adhesive on edges of neoprene pouch. Press pouch into the top surface of the bottom backpack
compartment. Allow to dry. For easy access pouch follow 25-27; except the easy access
pouch will be attach on the inside perimeter of the easy access panel.
Drill hole on the bottom right side of shell in appropriate location for power switch.
Apply sealer to edge of hole. Pop power switch into hole and hold. Wipe off any excess sealer and allow to dry. Drill hole in the bottom of the shell for the power cord. Drill hole in specified location on top access panel for light
sensor. Place light sensor in through the shell. Apply sealant to back of the sensor to hold in place. Allow to dry. Disconnect chest strap clip from strap. Slide user control panel onto strap. Reconnect chest strap clip. Wire all components.
Battery Health Panel:
Press fit PCB into top panel Apply silicone sealer to back Fit back panel against the top Clamp and allow to dry for appropriate time
LightsSelection
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Lights: Compared thru-hole vs. flexible strips
Strips proved to be better for application
Colored LEDs documented to be more efficient than using white LED with colored lens cover
Strips available in .5m length w/ 30 LEDs/strip Can be cut into increments of 3 LEDs
Each 3 LED segment has necessary resistors to operate @ 12V
3 sets of High Intensity 30 LED SMD Strips 2 amber and 1 red $15/ strip, $45 total
*Note: 11 sections of red strips are needed, but only 10/ strip Will instead use one amber section, but will purchase 2nd red strip in MSDII if budget
allows
Flexible LED Strip
LightsFlash Functionality
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Lower Small Arrows
Dual Brightness Running/Brake Lights
Upper Small Arrows
Upper Large Arrows
2nd stage brake lights
1st stage brake lights
LightsRequirements
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Purchase:1 RED strip2 AMBER strips
*Note: Decision made to eliminate front shoulder strap lights due to installation complexity and marginal benefit to rider (headlight is much brighter)
Light CoversSelection
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Lens Covers: Provide protection from elements Clear thermoform acrylic sheets
Can bend to required shape Clear:
~92% Light Transmission @ 90 degrees incident to surface Red and Amber:
~9-15% Transmission @ 90 degrees Currently in discussion with manufacturer
Will be sending free samples of both clear and red Can hold off on purchasing until samples are received
Sheets will be cut to size and molded to sit flush with External ShellDiffusion Material:
Diffusion material is not necessary and will not be used Could potentially be added after completion of build
Clear acrylic
Electronics Housing22
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Electronics Housing Assembly
Components• Main Housing• Base (Aluminum)• Long side (on battery side,
straight, 2 holes tapped on top)• Long side (dividing board and
battery, has slot for wires)• Long side (battery side, has 5
holes (2x DB9, I USB 2x 2-in-1) and 2 holes tapped on top)
• 2x Short side (identical, each has slot in the top)
• Top piece• 4 screws• Glue
Assembly1. Use mill to dimension
pieces to specified dimensions
2. Create required holes (tapped and for plug)
3. Glue long sides and short sides to base as detailed in assembly drawing
4. Add board, with bushings underneath
5. Install board with screws
6. Install top with screws
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Transmitter Box24
• Original plans were to fabricate a custom-sized waterproof box for the transmitter
• Availability and competitive prices of prefabricated boxes outweigh the benefits of a custom box
• Selected box: HAMMOND Plastic Instrument Enclosures Black Project Box
Pictured: Bottom (facing up and down) Complete box
Price: $4.49 (free shipping)
Chest Strap User Control Panel25
Control Panel (Cover Off)
Control Panel (w/ Cover)
View of Attachment Loop
Hazard Button
Light Pattern Select
Brake/Turn Signal Function Toggle
Status LEDs
Status LED On/Off
Chest Strap User Control Panel26
Control Panel Top
Control Panel Bottom
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Cord Retraction
• In order to prevent the charging cable from being caught in the rear wheel if disconnected, a retraction system is necessary.
• Original plans resembled a retractable dog leash, but because of the size and stiffness of the wire this idea was abandoned.
• Rather than have the wire wind up, it will be an extendable coiled wire with the male and female ends being the connectors.
Quick-Connect Selection Criteria28
Must attach and detach both quickly and easily Must not shake loose Must have reasonable detaching pull force in order to prevent damage to other systems
(if rider forgets to unplug) Aesthetically pleasing Low production cost
3 = Good2 = Okay1 = Poor
Wire Connected to Buckle/Bayonet clip
Wire in Magnetic Housing
Laptop-Style Connection
Guitar-Style Connection
Quick to Attach (Preferable)
2 3 2 3
Will Release Automatically (Important)
1 3 3 3
Not Prone to Shaking Loose (Important)
3 3 2 2
Complexity 2 2 3 3Aesthetics 1 3 2 3Points 9 14 12 14Continue to cost analysis? no yes yes yes
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Cost analysis of Quick-Connect options29
Guitar Amp ConnectorPart cost $4.36Tax $0
(included)Shipping $1.37Total $5.73
Magnetic Housing style
Component
Connector Plastic
Magnets
Part cost $7.98 $9.96 $3.00Tax $0.64 $0.80 $0.24Shipping $6.99 $5.00 $12.98Total (each piece) $15.60 $15.75 $16.22Total $47.58
Laptop-style Connector
Part cost $7.98Tax $0.64Shipping $6.99Total $15.60
Choice: Guitar Amp ConnectorReasons: -Quicker to attach because of no directional preference - “Clicks” in, less likely to come off accidentally
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System Block DiagramSystem Block Diagram BackpackElectronics Housing/PCB
Motorcycle System
Motorcycle Battery12VDC
Transmitter Housing/PCB
Quick Connect
12V->3.3V Regulation
Xbee Transmitter
1
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Transmitter Signals1. Headlight2. Left Turn Signal3. Right Turn
Signal4. Brake Light
AC/DC12VDC
System NiMH Battery12VDC
USB Charger
USB 2.0
5V12V
12V12V12V
XbeeReceiver
3.3V
Chest Strap PCB 12 LED Groups
Battery Monitor / Fuses
Battery Status LEDs
µCon (MSP430)
Voltage Regulation12V->5V5V->3.3V
12V
DarlingtonLight Drivers
Calibrate Button
User Interface Buttons
Chest Strap Signals1-4. Battery Status LEDs5. Function Toggle6. Function Toggle Sel7. Hazard8. 3.3V
12 4 63 5 7 8
2.5mm Connector
2.1mm Connector
Power Switch
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Battery SelectionTechnology
Re-evaluated initial selection of Li-Po battery due to safety concerns For scope of project, not possible to design box that is
guaranteed to prevent any damage to battery in event of crash
Li-Po and Li-Ion battery can catch on fire if cells are damaged, even with no current draw
Decided upon Ni-MH: They do not catch fire when damaged Still meet performance requirements Downside, heavier and larger volume
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Battery SelectionCriteria
Battery selection criteria: Meets minimum 12V voltage requirement (from lights) Meets minimum required power draw Meets maximum current draw (~3.5A worst-case) Can be connected to off-the-shelf AC smart charger
Built in overcharge protection and thermal monitoring
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Battery SelectionComparison
Three options Selection limited due to required capacity Selection further limited due to 12V requirement
Total price includes pack, charger Cost between 3 choices was negligible
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Battery SelectionComparison
After comparing in PUGH diagram, Powerizer Flat pack/charger was chosen due to flat size and larger capacity for the same price 4500 mAh, 12V, 4.2A max Dimensions: 7.2 x 2.9 x .8 inches Cost: $66, shipped 5 day lead time before shipping
Battery Health Monitor SelectionCriteria
Battery Health Monitor Criteria: Monitor voltage levels on NiMH Battery (14.5V-10.5V) Be able to load shed USB charging system at a
specific voltage. Shut off system as safe shutdown (10.5V) Send signals to Battery Status LEDs on chest strap
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Battery Health Monitor/Charging Circuit Function
Monitor Internal Battery Voltage Send Low Bat signal to µCon at desired level
Isolate Internal Battery from system under the following conditions. Low Battery Level Connected to: Wall Charger or Bike PowerBattery Voltage % Comments
14.5-13.5v 100-75%
13.5-12.5v 75-50%
12.5-11.5v 50-25%
11.5-10.5v 25-0%
10.5-10v 0% Isolate battery, and turn on indicator LED
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Battery Health Monitor DesignDesign
Compare the voltage on the supply to a reference voltage. Divide voltage supply level by 3. Use a 6.2V 1% precision Zener diode to set reference. Use voltage divider resistor string to set reference
voltage levels. 100% 75% 50% 25% 0% Comments
>13.5V
4.5V 4.52V
L L L L L
>12.5V
4.17V 4.19V
H L L L L
>11.5V
3.83V 3.85V
H H L L L
>10.5V
3.5V 3.52V
H H H L L
>10V 3.33V 3.35V
H H H H L System=OffIndicator=On
=10V 3.33V 3.35V
H H H H H Full-System=Off
Battery Monitor/Charging Schematic38
Comparators
Low-Battery Flag to µCon
1% PrecisionZener Diode
Power SupplySelection Criteria / Design
Power Supply selection criteria: Low power dissipation. Low heat generation. Regulate battery voltage to 5V for USB Charging
System Regulate battery voltage to 3.3V for µCon, Wireless,
User Interface switches and Battery Status LEDs.Power Supply Design
Vin >10V, 5V Switching Regulator, designed using Manu. Datasheet.
3.3V Linear Regulator using input from 5V Switching Reg.
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Power Supply Schematic40
5V Switching Regulator 3.3V Linear Regulator
USB Charger Selection Criteria /Design
USB Charger Selection criteria: Meet requirement of Standard USB Dedicated
Charging Port Maximize charging rate, while minimizing power/time.
USB Charger Design IC Solution for a Dedicated Charging port. 1A Charging Current
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USB Charger Schematic42
USB Enable from µCon
Dedicated Charging Port
Controller
Light Sensor SelectionCriteria
Light Sensor selection criteria: QSD124 NPN Silicon Phototransistor Narrow Reception Angle of 24DEG Power Dissipation is Max 100 mW
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Light Sensor Schematic44
LED Driver Selection
Drive a # of 3-LED segments requiring 200mA/segment.
Switch on/off using a µController input signal 0V->3.3V
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LED Driver Schematic46
Wireless Transmission SelectionCriteria
Xbee 802.15.4 Low-Power module w/ PCB Antenna Little configuration required for RF Communication Low-Power Consumption Low Input Voltage (3.3V) and Current (50mA)
requirements Small Physical Size Large amount of open-source documentation
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Transmitter (Tx) Board Schematic48
Voltage Regulation
Inputs
Transmitter Bike Signals
Microcontroller SelectionCriteria
Microcontroller selection criteria: Minimize controller power consumption. Maximize # of I/Os. Have PWM functionality.
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Microcontroller and Rx Schematic50
Xbee Receiver
Outputs to Light Drivers
µController w/ JTAG Prog.
Chest Strap System SelectionCriteria
Chest Strap criteria: House User Interface Switches House Battery Status LEDs Minimize Power Consumption Can be connected to off-the-shelf AC smart charger
Built in overcharge protection and thermal monitoring
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Chest Strap Schematic52
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Pseudo-Code (1/2)
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Pseudo-Code (2/2)
Continued from above
Overall Bill of Materials55
Overall Bill of Materials56
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High Cost Items
Battery- $66 w/shippingLights- $53 w/shippingMicrocontroller Dev. Kit - $29Xbee Units - $38PCBs- (3x$75) Shell Mold Fabrication- $135 w/shipping
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III. FEASIBILITY ANALYSIS, PROTOTYPING & EXPERIMENATION
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Light SystemLuminosity Test
• Three tests completed:• LED florescent tube strip (benchmark)• 4.4W 30 LED high power strip• 1.1 W 30 LED water resistant strip
• Tested high-brightness and weatherproof light strips in daylight
• Observed brightness ~100 ft away from light• All strips bright enough during day
Illuminated Light Strip*Note: Strip was much brighter than picture shows
Results: Lights bright enough for requirements
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Light SystemPower Consumption Calculations
Results: With very conservative estimate, in worst-case scenario, system should operate from battery for >2 hrs
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Bike Mock-UpTransmitter Box
1.75” 4”
1”
• A mock-up for transmitter placement was completed on donor bike
• Test-fit laptop charger into inner cover• Dimensions are 1.75 x 4 x 1 inch (H x L x W)
• Charger fit within cover with extra room• Transmitter box will be much smaller than charger => fits• Inner cover is protected from elements from outer cover (not
pictured)
Inner Cover
Charger
Results: Good location determined for Tx box
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Bike Mock-UpBike Battery Power Wire Routing
• Proper routing of the wire from the 12V bike battery is very important for several reasons:
• Mitigation of any risk that wire can catch on rider• If wire detaches, should not create safety risk (i.e. catch in
chain/wheel)• With wire attached, rider should be able to move freely• Rider should be able to easily attach wire
• Considered several routing options:• 1. In front of seat• 2. Rear of seat• 3. Side of seat
# 1
# 3# 2
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Bike Mock-UpBike Battery Power Wire Routing: Option 1
• Option 1 quickly eliminated due to routing over rider’s legs• Safety and rider discomfort issues
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Bike Mock-UpBike Battery Power Wire Routing: Option 2
• Option 2 is possible, but not ideal• Space under seat for wire to route without any stress
concerns• However, wire would have to route over seat, which could
blow around in wind and create greater risk of detachment
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Bike Mock-UpBike Battery Power Wire Routing: Option 3
• Option 3 presents best routing method• No interference with rider• No stresses/ methods for damage to wire• Shortest wire length of 3 options
Mock-up Wire Routed with Seat on
Space between frame and chrome
Results: Option 3 is best method
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Xbee Code
Configures the TX unit +++ -Grabs unit attention ATRE -Resets ATID 2286 -Sets address ATMY 1 -Sets my address to 1 ATD0 3 ATD1 3 ATD2 3 ATD3 3 -Sets DIO 0 through 3 to digital input ATDH 0 -Sets destination address high ATDL 2 -Sets destination address of receiver ATIR 14 -Sets sample rate to 20ms ATPR 0 -Disables internal pull-ups ATWR -Writes to memory
Configures the RX unit +++ -Grabs unit attention ATRE -Resets ATID 2286 -Sets address ATMY 2 -Sets my address to 2 ATD0 5 ATD1 5 ATD2 5 ATD3 5 -Sets DIO 0 through 3 to digital output ATIA 1 -Sets I/O input address to TX address ATWR -Writes to memory
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IV. TEST PLAN
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V. NEXT STEPS
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Updated Risk Assessment (1/3)
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Updated Risk Assessment (2/3)
6Multiple units cause interference.
Device does not function properly when multiple devices are in close proximity.
No design consideration for transmitting/receiving frequencies.
1 2 2Selected Xbee electronics technology that has large frequency range. Will pair devices at unique frequency.
Eric, TJ, Mike
7System doesn’t provide adequate light visibility.
No enhanced safety to other motorists.
Improper light selection luminosity and/or location. 1 3 3
Benchmarked existing light designs, purchased light strips and tested daylight visibility.
Eric, Mike, TJ
11Unsatisfactory appearance of product. Customer unhappy. No attention to aesthetics. 1 1 1
Consulted Industrial Design student, and conducted mock-ups of design concepts. Will receive feedback from customer on satisfactory design appearance.
Tyler
12Cannot find a motorcycle to modify.
No final deliverable. Untestable product.
Poor communication between team members. 2 3 6
Found donor motorcycle to add equipment to, and take preliminary test measurements on. Mike, All
13Device difficult to install on customer’s vehicle.
Reduced value of product to customer.
Poor consideration to interface with vehicle. 2 1 2
Took preliminary measurements on motorcycle, inspecting wires and least-intrusive method to modify. Will continue to reference customer vehicle throughout design process.
Mike, All
20Team mate(s) have to complete work assigned to others.
Team member(s) do more than fair share of work, reduction in overall quality of work.
Non-committed team member(s), not asking questions, agreeing to tasks but not following up.
2 3 6Poor peer reviews if expected work is not completed. Meetings with advisors. All
21Mold is unable to be manufactured
Desired backpack shell is unobtainable, reduced functionality in system.
Improper material selection, high manufacturing costs, no consideration for design for manufacturability
2 2 4Consultation with Brinkman lab specialists and/or ID students. Select materials while considering cost
Tyler
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Updated Risk Assessment (3/3)
22Bike light signals are too noisy
Inability/ limited ability for microcontroller to process signal wave form.
Noise from electronics on bike or environment, improper wire shielding, improper signal filtering
1 3 3 Proper wire selecting, proper signal filtering Eric
23Transmitter does not send proper signal to the backpack
Backpack lights do not function, or are not synced with bike. Improper wireless system coding 1 3 3 Test code and system functionality TJ
24Unable to completely sync with bike's brakes and turn signals
Backpack lights are not synced with bike, frequency mismatch between systems.
Incorrect edge detection sampling and timing within microcontroller
1 2 2 Test code and system functionality Eric
25PCB does not fit in the electronics housing
PCB is exposed to outside environment.
Dimensional mismatch between PCB and housing 1 3 3
Communication of dimensions between PCB designer and housing designer Ben
26Battery does not fit in the electronics housing
Battery is exposed to outside environment, cannot power system.
Dimensional mismatch between battery and housing 1 3 3
Communicated of battery dimensions to housing designer Ben
27Transmitter box does not fit in the decided location on the bike
Transmitter board is not properly housed, PCB is exposed to outside environment.
No investigation into on-board bike dimensions before transmitter housing design
1 3 3Took measurements on bike, presented maximum dimensions to housing designer Ben/Mike
28Power quick connector unable to disconnect in a crash scenario
Potential safety risk to rider.Poor consideration to quick connect design 1 3 3 Test quick connect release force requirements Ben
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Power quick connector disconnects do to wind, vibration, or other riding conditions
Potential safety risk to rider, backpack system no longer powered from bike.
Poor consideration to quick connect design 1 3 3
Test quick connect system on bike at maximum required speed Ben
30Backpack assembly falls apart during testing
Electronics, lights, or shell are damaged.
Poor attachment/adhesion of zippers or shell 2 3 6
Proper selection of adhesive. Consideration of manufacturing methods. Tyler
31 Random act of GodSubsystems destroyed beyond repair. Unpredictable disaster 1 3 3 Store components in secure location All
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MSD II Plan- Overview
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MSD II Plan- Overview
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MSD II Plan- 4 week plan
• End Week 1• Complete Final Assembly and Test Plans- All
• End Week 2• Completed Assembly of Transmitter Housing- Ben• Completed Assembly of Transmitter Board- TJ• Completed Debugging of Transmitter Housing- TJ
• End Week 3• Completed Assembly of In-bag Electronics Assembly- Ben• Completed In-bag Assembly Board- Eric/TJ• Completed Backpack External Shell- Tyler/Mike• Completed DC Quick Connect Assembly- Ben
• End Week 4• Completed Backpack Shell Integration w/Soft Shell- Tyler• Completed Light/Light Cover Integration w/Shell- Mike/Tyler• Completed Debugging of In-Bag Assembly- Eric/ TJ
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VI. CONCLUSION, COMMENTS
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Questions