1. P15043- Smart Cane Systems Integration
Justin LaMar (EE)
Emeka Akpaka (EE)
Kayla Cole (ISE)
Lindsay Johnson (ISE)
Christine Lochner (ME)
Nick Stewart (ME)
Final Demo – Multidisciplinary Senior Design II
May 7, 2015

2. Agenda Project Overview Customer Requirements Engineering Requirements
System Design and Development
Testing
System Integration
Current Project Status
Budget and Manufacturing Costs
Lessons Learned
Questions

3. Customer Requirements
Customer Rqmt. #
Importance
Description
CR1 9
Detect objects to the front, right, and left of the user and communicate directly to the user
CR2 3
Does not add much weight
CR3
Reduce number of small parts from existing concept
CR4 1
Adequate battery life
CR5
Rechargeable battery
CR6
Collapsible into equal sections
CR7
Low manufacturing cost
CR8
Design assembly process to be completed in a blind assembly environment
CR9
Short collapse/re-assemble time
CR10
Adequate detection range
CR11
Safe to use
CR12
Comfortable for the user
Importance: Sample scale (9=must have, 3=nice to have, 1=preference only)

4. Engineering Requirements
Rqmt. #
Importance
Source
Function
Engr. Requirement (metric)
Unit of Measure
Marginal Value
Ideal Value S1 9
CR1
System Operation
Provide 90 degree detection range in front of user
Degrees 90 S2
Signal detection of obstacles
Binary
Pass S3 3
CR2
System Portability
Adds no more than 1 lb to standard white cane
Lbs 1 S4
CR3
System Assembly
Decrease amount of visible hardware by 50% compared to P14043
Pieces 15 10 S5
CR4, CR5
8 hour rechargeable battery (minimum battery life)
Hours 8 S6
CR6
Collapsible into 8-10" sections
Inches S7
CR7
System Cost
Manufacturing cost $125 or less
USD
125 S8
Systems Operation
Intuitive Haptic Feedback S9
CR9
System Usability
Keep cane collapse/re-open time less than 1 minute
Minutes
S10
CR10
Horizontal detection range
Feet 6
S11
CR12
Maximum pressure feedback can withstand
psi 5
S12
System Structure
Handle contents fit within handle mock up envelope
S13
Maximum handle grip diameter in
1.5
1.3
Importance: Sample scale (9=must have, 3=nice to have, 1=preference only)

5. Mechanical Review

6. Mechanical Requirements: Actual Values
Rqmt. #
Importance
Source
Function
Engr. Requirement (metric)
Unit of Measure
Marginal Value
Ideal Value
Actual Value
Test (how actual value was found) S3 3
CR2
System Portability
Adds no more than 1 lb to standard white cane
Lbs 1
0.369 (added to standard cane)
Final weight was found using a triple beam balance. A battery was also included in the final weight. S4
CR3
System Assembly
Decrease amount of visible hardware by 50% compared to P14043
Pieces 15 10 12
Based on the current design there will be 12 screws + washers on the outside of the handle. This was determined by counting the connection points where we plan to fasten the pieces together. S8 9
CR1
Systems Operation
Intuitive Haptic Feedback
Binary
Pass
A survey was given to 25 people: 56% said it was easier to tell what side the bearings were actuating on than they expected 40% said the ease of telling what side the bearing were actuating on was as expected 

7. Mechanical Requirements: Actual Values
Rqmt. #
Importance
Source
Function
Engr. Requirement (metric)
Unit of Measure
Marginal Value
Ideal Value
Actual Value
Test (how actual value was found)
S11 3
CR12
System Operation
Maximum pressure feedback can withstand
Binary
Hand grip does not stall motor
We attempted testing the grip pressure, but could not find an accurate way to ensure we knew what pressure was pushing down. During Image RIT a large number of people tried the cane and the motor did not appear to stall and there was no excessive heat up due to torque on the motor.
S12
System Structure
Handle contents fit within handle mock up envelope
Pass
Everything fits except circuit board.
The custom printed circuit board does fit, but the back-up soldered board does not. In the future a larger board housing could be printed to accommodate the slightly larger board.
S13 9
Maximum handle grip diameter in
1.5
1.3
≈1.3
The handle is not completely circular so the radius varies a bit, but when measuring the OD with calipers it is about 1.3 in. Based on survey results, this diameter may bit a little large for comfort.

8. Haptic Feedback

9. Handle Design

10. Review of Mechanical Problems
Date Added
Identifying & Selecting Problem PSP 1
Analyzing Problem PSP 2
Generating Potential Solutions PSP 3
Selecting & Planning Solution PSP 4
Implementing Solution PSP 5
Evaluating Solution PSP 6
Rating R0 R1 R2 R3 Y4 Y5 G6
MAJOR
2/24/2015
3D Printing Cane Handle - Ease of Printing/Print Quality
Quality of print might not be to desired specification
Discuss options with Lab Manager (Mike Buffalin)
Find times to meet with Mike Buffalin for discussion
Swapped contact info and made meeting times
Found a place to print the 3D parts that has a lot of availability
4/14/2015
Motor oscillation drifts counter-clockwise
• Not due to torque applied to motor (drift still occurs when no weight is applied) • Must be inherent slip in the gears
• Use sensors to stop the oscillation from drifting • Set up stoppers in the cane made of Teflon or UHMWPE • Pad the windows where the arms oscillate to stop the motion from harming the plastic shell
Do nothing unless it becomes a problem. If it is an issue put a stopper in.
Once the bearing arms were running in the handle (completely closed) the oscillation drift was insignificant. During gear slip the arm bumps gently into the side of the handle and goes back into the right spot.
The feedback ran continuously for several hours at Imagine RIT and there didn't seem to be any issues with drifting oscillation or excessive heat up due to torque.

11. Review of Mechanical Problems
Date Added
Identifying & Selecting Problem PSP 1
Analyzing Problem PSP 2
Generating Potential Solutions PSP 3
Selecting & Planning Solution PSP 4
Implementing Solution PSP 5
Evaluating Solution PSP 6
Rating R0 R1 R2 R3 Y4 Y5 G6
ORDINARY
3/2/2015
When bearing rolls over hand both the bearing and bearing arm are in contact with skin
Only the roller should be in contact with skin
•Buy a different bearing • Put material over the current bearing to make it wider • 3D print a bearing to our exact desired dimensions • Shave material off bearing arm
3D print different bearings with larger outer diameter.
The bearings are completed
Problem fixed!
3/17/2015
3D Printing Tolerance Quality
The MakerBot doesn’t use actual dimensions, only proportions
• Re-print section(s) if necessary • Sand down components • Possibly saw off edges
• Currently focusing on sanding down components • The dimensioning was off between the red and blue makerbots causing issues with joining the two sides
• The dimensioning was off between the red and blue makerbots, so we decided to re-print the red pieces on the blue machine….Printing is in progress
• Dimension tolerances are more similar when printed on the same machine, therefore we went back and printed the rest of the handle's curved parts on the same machine. The helped the radiuses be close enough to connect the pieces.

12. Weight Measurements Total Smart Cane Weight: 0.92 lbs
Weight of a standard cane: 0.55 lbs
Weight added to a standard cane: 0.37 lbs
Demographic Info: Percentage of adult population that can sustain this weight:
99.74% of Males
95.80% of Females

13. EE Focus Customer Rqmt. # Importance Description
Requirement Has Been Satisfied
CR1 9
Detect objects to the front, right, and left of the user and communicate directly to the user
Need to perform testing first
CR4 1
Adequate battery life
Yes (8 hours)
CR5 3
Rechargeable battery
Yes
CR10
Adequate detection range

14. EE Engineering Requirements
Rqmt. #
Importance
Source
Function
Engr. Requirement (metric)
Unit of Measure
Marginal Value
Ideal Value
Actual Value
Test (how actual value was found) S1 9
CR1
System Operation
Provide 90 degree detection range in front of user
Degrees 60 90
120
Will be achieved by a combination of the user's sweeping motion and 2, 25 degree range sensors
S10
CR10
Horizontal detection range
Feet 6 8
8.5
Using A Person S5 3
CR4, CR5
8 hour rechargeable battery (minimum battery life)
Hours
>8

15. Layout of Subsystems

16. Hardware Design

17. Hardware Implementation

18. Software Design

19. Prototype

20. Troubleshooting Motors create noise
Mucks up the accelerometer signals and sonar sensor signals
C version for the microcontroller does not function as intended
Stops us from using the microcontroller

21. Motor Draw

22. Problem Tracking

23. Moving Forward Solving the motor draw issue
Solving the programming issue
Integrate and finalize the PCB with the cane handle
Celebrate

24. Imagine RIT Survey Result
25 people took a survey → Age of people varied (8yrs & up)
How easy was it to tell what side the bearings were moving on?
Less Easy Than Expected
As Expected
Easier Than Expected 4%
40%
56%
How comfortable is the diameter of the cane handle?
Less Desirable
Better Than Expected
12%
60%
28%
Was the right bearing in a location your hand could reach?
Not at all
Yes, but barely
Yes
88%
Was the left bearing in a location your hand could reach?
4% (8 yr. old)
16%
80%
Additional Comments: *Heavy *Sensor is too sensitive *Left bearing should be positioned differently *Make handle feel sturdier *Needs more hand contours (ergonomic) *Fit handle size to person's hand size (S, M, L) *Make a more compact design *Create left handed version

25. Amount Covered By Contingency
Budget
Spent $870 of our $1,000 budget
Significantly more than the teams original spending plan ($495)
Saved money on 3D Printing (free!)
Majority of spending was a result of the need for multiple PCB iterations
Cost Category
Amount Spent
Amount Remaining
Amount Covered By Contingency
Motors $ $
Mechanical $ $
$ (23.92)
Printing Material $
Electrical $
$ (458.36)
Contingency
$ (27.29)
General Other $
$ (50.01)
Total $ $ $

26. Manufacturing Cost Exceeds customer requirement of $125
Can be lowered by increasing quantity or changing cane material
ABVI Givens:
Harbec Quotes:
Fixture Cost*
Unit Cost
Overhead Rate
11%
Cane top
$ 19,980.00 $
Hourly labor rate** $
Cane bottom $
Assumed Quantity
500
Sensor cover
$ 8,450.00 $
Per Unit
Total bulk cost of off the shelf components $
Cost of PCB $
*Fixtures are guaranteed for 500,000 pieces
Total cost of plastic parts $
**Not included in estimate
Total $
With overhead $

27. Lessons Learned
Plan to spend more time on new concepts (PCB development)
Regardless of how it may seem, you do not have a lot of time
Perform as many tasks in parallel as possible
Leave room in the schedule for unexpected work/re-work
Work and make decisions as a team, not just as a sub-discipline
Take time to invest in your team dynamic

28. Questions?