P15418: Better Water Maker

Jason AndrewsTyler Burns

Maxamillion McMahonNicolas Reginelli

Tyler SchmidtAnna Sementilli

Guide: Gerry GaravusoCustomer: B9 Plastics

AgendaProject DescriptionRequirements SummaryConcept and Design SummarySystem ArchitectureCompetitive AdvantageTesting ResultsProject EvaluationRecommendations for future workLessons Learned

Project DescriptionThe goal of this project is to

improve B9 Plastic’s Better Water Maker. The Better Water Maker works by reducing the number of dangerous waterborne microbes via the use of a UV bulb. Two different designs have been tried in the past, with the current version utilizing a hand crank flywheel as a method of mechanical power generation. The major goal is to design the power system so that it generates the required power with less human effort. The current UV treatment process must not be altered.

Requirements SummaryEngineering Requirement

Description Metric Target Value

Marginal Value

ER1 Power Generated

Power (V/A/W)

12/2.5/17

+3/-0

ER2 Training Time Time (minutes)

20 +10

ER3 Installation Time

Time (minutes)

90 +/- 30

ER4 Effort Required

CO2 L/Min .9 -.9

ER5 Number of Installers Required

# People 1 1 or 2

ER6 Unit Life Life of Parts (Yrs)

2 -0.5

ER7 Electrical Protection

Voltage (V), Current (A)

25/3 +0/-3

Concept and Design SummaryBegan with:

PlywoodStepped gear box

Moved to:Custom gear for correct ratioSolid AL plate

Ended with: Static line for pulleySprocket and chain system

Concept and Design SummaryFinal Design:

Ratio of ~15 through the use of sprockets

Turned out to be a little unbalancedGears… Heat, friction, stretch = energy loss

Improvements: In need of a lighter, cheaper redesignLonger base supportsSprocket & chain connected to

pedalsCover for safetyAlternative way to hold yourself upSome adjustability

Concept and Design Con’tAccomplished:

Speed to create powerWorking prototype

Lessons Learned: Design early, allow for

time for redesignsDesign with assembly in

mindModels can be misleading

Missed the mark: Cost more than anticipated Some parts showed

extreme wear characteristics

Safety concerns regarding sprockets

Loud noise the prototype makes while operated isn’t pleasant

System Architecture

Competitive AdvantageDesign chosen due to increased efficiency

with use of leg muscle vs arm muscle

Standing concept allows use of full body weight

Stepping is a more natural motion

Allows for a high gear ratio, reducing total work and lactic acid build up

Testing Results-Power GeneratedMotor Output-18.4V,2.9A,53W

Buck Converter Output- 15V,2.9A,43.5W

Testing Results-Electrical Protection3A fuse failed (as expected) with a 4.5Ω load

at 15V (3.33A)Max voltage is limited to 25V by a capacitor

in the Buck Converter The UPS system also has a 3A fuse and the

components can handle 40V

Testing ResultsHand Crank-max CO2=.85(L/m)

Treadle System- max CO2=1.42(L/m)2.5 steps/second.48 Gal/Min

Ramp up to required SPS

Pump Delay

Pumping Water

Project EvaluationElectrical

Power generated was satisfied with 1 motor generating ~18.4V/2.9A/53W.

Electrical protection put in place to protect circuitry against a 3A surge in current with buck converter regulating voltage to 14.8V.

Battery Management System added to compensate for non-periodic motion of motors and so users will not exert energy for 10 seconds to power on light. System was designed to charge at 500mA @ 15V

and to trickle charge at ~20mA @ 12V.

Project EvaluationMechanical

Treadle system designed to take advantage of leg strength and body weight.

Easier to sustain a constant motion as compared to hand crank. Step rate: 2.53 steps/sec which is at a faster pace than what

was designed for. Add flywheel to keep motion constant and reduce step rate.

Pulley identified as the failure point of the system. Plastic coated steel cable or spring/bungee pedal return

system could be a solution.System could be too complex for people in the third

world to assemble properly

Engineering Requirement

Description Metric Target Value

Marginal Value

Actual Performance Rating

Was the requirement

satisfied?

ER1 Power Generated

Power (V/A/W)

12/2.5/17

+3/-0 Power generated was satisfied by generating ~18.4V/2.9A/53W

Yes

ER2 Training Time Time (minutes)

20 +10 Not formally tested for but observed during Imagine; determined that the training time for a child to use the system is <20 minutes

Yes

ER3 Installation Time

Time (minutes)

90 +/- 30 System could be too complex for people in the third world to assemble properly

No

ER4 Effort Required CO2 L/Min .9 -.9 Step rate: 2.53 steps/sec which is at a faster pace than what was designed for; Hand crank requires less effort

No

ER5 Number of Installers Required

# People 1 1 or 2 Because of the weight of the system and the complexity, more than 1 installer will be required

No

ER6 Unit Life Life of Parts (Yrs)

2 -0.5 Pulley identified as the failure point of the system

No

ER7 Electrical Protection

Voltage (V), Current (A)

25/3 +0/-3 Electrical protection put in place to protect circuitry against a 3A surge in current with buck converter regulating voltage to 14.8V

Yes

Schedule and BudgetBudget: $1,000Actual Spending: $940

Project Plan: We fell behind at times during the year but it came together in the endThings left to do:

Finalize Paper Final Review Final Peer Reviews Update Edge

Recommendations for future work• Weight reduction would be a great way to

improve this design• Experiment with wrapping rope around

the shaft• Add flywheel to help reduce the required

step rate• Simplify amount of parts in product• Include stronger pulley/better pedal

return system• PCB layout for UPS system

Lessons LearnedCommunication: External (customer) and

internal (project team) communication should be more frequent and consistent. Have written agreements for decisions and goals.

Planning: Plans constantly change and evolve. Tasks like testing the system will often take longer than anticipated and may introduce issues that further extend timelines.

Risks: Discover as many risks as you can. Make sure you account for a lot possibilities, from very likely situations to those you’d never expect to occur.

Execution: Teamwork is essential. Share roles and split up work to get things done faster and more efficiently.

Questions?