P15043- Smart Cane Systems Integration

P15043- Smart Cane Systems IntegrationFinal Demo Multidisciplinary Senior Design IIMay 7, 2015Justin LaMar (EE)Emeka Akpaka (EE)Kayla Cole (ISE)Lindsay Johnson (ISE)Christine Lochner (ME)Nick Stewart (ME)

1AgendaProject OverviewCustomer RequirementsEngineering RequirementsSystem Design and DevelopmentTestingSystem IntegrationCurrent Project StatusBudget and Manufacturing CostsLessons LearnedQuestions

2Customer RequirementsCustomer Rqmt. #ImportanceDescriptionCR19Detect objects to the front, right, and left of the user and communicate directly to the userCR23Does not add much weightCR33Reduce number of small parts from existing conceptCR41Adequate battery lifeCR53Rechargeable batteryCR63Collapsible into equal sectionsCR73Low manufacturing costCR81Design assembly process to be completed in a blind assembly environmentCR93Short collapse/re-assemble timeCR109Adequate detection rangeCR119Safe to useCR123Comfortable for the userImportance: Sample scale (9=must have, 3=nice to have, 1=preference only)3Engineering RequirementsRqmt. #ImportanceSourceFunction Engr. Requirement (metric)Unit of MeasureMarginal ValueIdeal ValueS19CR1System OperationProvide 90 degree detection range in front of userDegrees90S29CR1System OperationSignal detection of obstacles BinaryPassS33CR2System PortabilityAdds no more than 1 lb to standard white caneLbs1S43CR3System AssemblyDecrease amount of visible hardware by 50% compared to P14043Pieces1510S53CR4, CR5System Operation8 hour rechargeable battery (minimum battery life)Hours8S63CR6System PortabilityCollapsible into 8-10" sectionsInches108S73CR7System CostManufacturing cost $125 or lessUSD125S89CR1Systems OperationIntuitive Haptic Feedback BinaryPassS93CR9System UsabilityKeep cane collapse/re-open time less than 1 minuteMinutes1S109CR10System OperationHorizontal detection range Feet610S113CR12System OperationMaximum pressure feedback can withstand psi35S123CR12System StructureHandle contents fit within handle mock up envelopeBinaryPassPassS139CR12System StructureMaximum handle grip diameterin1.51.3Importance: Sample scale (9=must have, 3=nice to have, 1=preference only)4Mechanical ReviewMechanical Requirements: Actual ValuesRqmt. #ImportanceSourceFunction Engr. Requirement (metric)Unit of MeasureMarginal ValueIdeal ValueActual ValueTest (how actual value was found)S33CR2System PortabilityAdds no more than 1 lb to standard white caneLbs10.369 (added to standard cane)Final weight was found using a triple beam balance. A battery was also included in the final weight.S43CR3System AssemblyDecrease amount of visible hardware by 50% compared to P14043Pieces151012Based 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.S89CR1Systems OperationIntuitive Haptic Feedback BinaryPassPassA survey was given to 25 people:56% saidit 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 expectedMechanical Requirements: Actual ValuesRqmt. #ImportanceSourceFunction Engr. Requirement (metric)Unit of MeasureMarginal ValueIdeal ValueActual ValueTest (how actual value was found)S113CR12System OperationMaximum pressure feedback can withstand Binary Hand grip does not stall motorHand grip does not stall motorWe 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.S123CR12System StructureHandle contents fit within handle mock up envelopeBinaryPassPassEverything 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.S139CR12System StructureMaximum handle grip diameterin1.51.31.3The 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. Haptic Feedback

Handle Design

Review of Mechanical ProblemsDate AddedIdentifying & SelectingProblemPSP 1AnalyzingProblemPSP 2Generating PotentialSolutionsPSP 3Selecting & PlanningSolutionPSP 4Implementing SolutionPSP 5EvaluatingSolutionPSP 6RatingR0R1R2R3Y4Y5G6MAJOR2/24/20153D Printing Cane Handle - Ease of Printing/Print QualityQuality of print might not be to desired specificationDiscuss options with Lab Manager (Mike Buffalin)Find times to meet with Mike Buffalin for discussionSwapped contact info and made meeting timesFound a place to print the 3D parts that has a lot of availability 4/14/2015Motor 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 shellDo 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. Review of Mechanical ProblemsDate AddedIdentifying & SelectingProblemPSP 1AnalyzingProblemPSP 2Generating PotentialSolutionsPSP 3Selecting & PlanningSolutionPSP 4Implementing SolutionPSP 5EvaluatingSolutionPSP 6RatingR0R1R2R3Y4Y5G6ORDINARY3/2/2015When bearing rolls over hand both the bearing and bearing arm are in contact with skinOnly 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 arm3D print different bearings with larger outer diameter.The bearings are completedProblem fixed!3/17/20153D Printing Tolerance QualityThe MakerBot doesnt 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.Weight MeasurementsTotal Smart Cane Weight: 0.92 lbsWeight of a standard cane: 0.55 lbsWeight added to a standard cane: 0.37 lbs

Demographic Info: Percentage of adult population that can sustain this weight:99.74% of Males95.80% of Females12EE FocusCustomer Rqmt. #ImportanceDescriptionRequirement Has Been Satisfied CR19Detect objects to the front, right, and left of the user and communicate directly to the userNeed to perform testing firstCR41Adequate battery lifeYes (8 hours)CR53Rechargeable batteryYesCR109Adequate detection rangeYesEE Engineering RequirementsRqmt. #ImportanceSourceFunction Engr. Requirement (metric)Unit of MeasureMarginal ValueIdeal ValueActual ValueTest (how actual value was found)S19CR1System OperationProvide 90 degree detection range in front of userDegrees6090120Will be achieved by a combination of the user's sweeping motion and 2, 25 degree range sensorsS109CR10System OperationHorizontal detection range Feet688.5Using A PersonS53CR4, CR5System Operation8 hour rechargeable battery (minimum battery life)Hours68>8Layout of Subsystems

Hardware Design

Hardware Implementation

Software Design

Prototype

TroubleshootingMotors create noiseMucks up the accelerometer signals and sonar sensor signalsC version for the microcontroller does not function as intendedStops us from using the microcontrollerMotor Draw

Problem Tracking

Moving ForwardSolving the motor draw issueSolving the programming issueIntegrate and finalize the PCB with the cane handleCelebrateImagine RIT Survey Result25 people took a survey Age of people varied (8yrs & up)

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

How easy was it to tell what side the bearings were moving on?Less Easy Than Expected As Expected Easier Than Expected4%40%56%How comfortable is the diameter of the cane handle?Less Desirable As Expected Better Than Expected 12%60%28%Was the right bearing in a location your hand could reach?Not at allYes, but barelyYes012%88%Was the left bearing in a location your hand could reach?Not at allYes, but barelyYes4% (8 yr. old)16%80%24BudgetSpent $870 of our $1,000 budgetSignificantly 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 iterationsCost CategoryAmount Spent Amount Remaining Amount Covered By Contingency Motors $ 47.85 $ 42.15 Mechanical $ 63.92 $ - $ (23.92)Printing Material $ - $ 115.00 Electrical $ 708.36 $ - $ (458.36)Contingency $ - $ (27.29)General Other $ 50.01 $ - $ (50.01)Total $ 870.14 $ 129.86 $ 532.29

25Manufacturing CostExceeds customer requirement of $125Can be lowered by increasing quantity or changing cane materialABVI Givens:Harbec Quotes:Fixture Cost*Unit CostOverhead Rate11%Cane top $ 19,980.00 $ 3.57 Hourly labor rate** $ 10.50 Cane bottom $ 19,980.00 $ 3.90 Assumed Quantity500Sensor cover $ 8,450.00 $ 2.16 Per UnitTotal bulk cost of off the shelf components $ 146.05 Cost of PCB $ 2.10 *Fixtures are guaranteed for 500,000 piecesTotal cost of plastic parts $ 9.63 **Not included in estimateTotal $ 157.78 With overhead $ 175.14 26Lessons LearnedPlan to spend more time on new concepts (PCB development)Regardless of how it may seem, you do not have a lot of timePerform as many tasks in parallel as possibleLeave room in the schedule for unexpected work/re-workWork and make decisions as a team, not just as a sub-disciplineTake time to invest in your team dynamicQuestions?