P18463: Water Powered USB Charger
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Build & Test Prep

Table of Contents

Team Vision for Build & Test Prep Phase

The main focus of this phase was updating the Bill of Materials with a finalized list of parts needed for product assembly and testing. With the list, we will begin to place orders for all of the parts we are certain we will need.

Components and tools needed for building and testing the device were reviewed and orders were successfully placed online. The anticipated cost of both building and testing the device have decreased significantly due to the elimination of excessive items as well as a change in the testing approach. Because the team is still testing and developing the product, new tools and components may need to be ordered in order to meet any challenges that may arise.

Design Updates

Turbine & Housing

-Changed to modular printing. Done to avoid 3D printing issues. As design is now printable on campus, it helps lower overall design costs. Below is a photo of the old vs new prop design.

Old Propeller Design

Old Propeller Design

New Propeller Design

New Propeller Design

-Detachable fins/blades is now a customer requirement. For that reason we came up with a dogbone design that lets the customer change out the fins without much hassle.

Dogbone Blade Holder

Dogbone Blade Holder

-New blade connection pieces that will hold the assembly such as the washer and screw setup on the motor side, and the propeller holding clip on both the ends (that the customer will have to pull off over the shaft to change out the blades if need be).

Propeller Holding Clip

Propeller Holding Clip

Generator & Voltage Regulator

We decided on ordering a 12V 500 RPM DC Motor. We felt that this was a good range based on our calculations. We went with a slightly higher quality motor because it will be just about the most important component of the device. Not much else has changed for the electrical layout. Not much is expected to change in the future either.

Packaging

The packaging design is one of the mechanical focuses in the next phase.

Now that the team has made the device significantly more modular, the packaging for it should be significantly smaller and cheaper to make. We are anticipating that the cable and rod accessories are the only thing that will exist outside of the device packaging due to their sizes.

Bill of Materials

We did a thorough analysis of our current Bill of Materials and decided on what items we actually needed to purchase. As a result a lot of items were removed. This in turn lowered our total cost from what it was at the end of Phase 4. On the Bill of Materials, there are 2 columns. One is total cost and another is cost per unit. Total Cost is the total cost of our prototype which includes only the required amounts of materials needed to build it, and their respective costs. The unit cost includes the cost of a whole item. For example, while our unit cost of wire is $60 for 100ft of wire, we are only using 40ft in our final device, so the total cost of the prototype will only be 40% of the the unit cost for wire. We decided to increase the amount of cable we are purchasing as well in case we end up needing more than expected. We also ordered 2 lip seals and bearings each in case something happens to one of them during testing. We have ordered several of the items already but we are waiting to order a few of them. We aren't ordering the PVC piping yet because we do not know the size required until we receive the rod anchor.

The current Bill of Materials can be found in the following link: Updated Bill of Materials

Test Plan Summary

The Master Test Plan Document can be found here: Test Plans

Voltage Regulator

Goal: Voltage regulator varies output current with respective to turbine rotational speed. The goal is to obtain 5V and at most 2A out of the voltage regulator and supplied to the power bank.

Satisfies: The customer prefers trickle charging which means the charger should be capable of supplying low amounts of varying current to charge the customer's device with no interruption of power being generated and supplied.

Voltage Regulator Test Plans

Voltage Regulator Test Plans

Generator

Goal: The generator should be capable of spinning fast enough to generate enough voltage to get transmitted to the voltage regulator. We are looking at somewhere around at least 2-6 V being generated due to water conditions.

Satisfies: The customer will see an end result of 5V and at least 2A being supplied to the powerbank.

Generator Test Plans

Generator Test Plans

Housing & Waterproofing

Goal: Show that the preventative methods of waterproofing the device are sufficient enough to keep water out of the housing and achieve an IP68 rating.

Satisfies: The device must be waterproof in order to function.

Waterproofing Test Plans

Waterproofing Test Plans

Turbine & Power Output

Goal: To achieve a current output from the device that lies between 1.5 and 3 Amps at a voltage of 5V. Ideally the current outputs will align with those from our simulations and calculations.

Satisfies: Device must output 1.5 to 3 Amps using the energy from moving water.

Turbine Test Plans

Turbine Test Plans

Risk Assessment

The Risk Assessment Document can be found here: Risk Assessment

Project Schedule & Milestones

The team has begun using Teamweek, the Google Docs of project management software. With it, we are able to quickly create and shift schedules as needed. We have also added anticipated milestones which include both design reviews and major progressions on the build.

Each of the remaining phases have been broken out into "Sub-phases", i.e. intervals that each last roughly a week. There are clear tracks for each team member, typically determined by engineering discipline. If things continue to run smoothly, the team is expecting a fully assembled prototype before the next review and a fully functional prototype approximately one week before the System Build Review in Week 10. A snapshot of the schedule for the next phase can be found below.

Teamweek Schedule

Teamweek Schedule

Design Review Materials

The Review Outline can be found here: Build & Test Prep Review Outline

The Project Summary Sheet can be found here: Project Summary Sheet


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