One of the best ways to combat viruses that spread through surface contact is through the regular, proper washing of hands.  While the CDC recommends washing hands for at least 20 seconds, studies have shown that the average amount of time people actually do is just 6 seconds!  You just started a new internship at a consumer electronics company.  They have an idea for a consumer product that will attach to faucets and use lights and sound to encourage both kids and adults to wash for an entire 20 seconds.  They’ve asked you to develop a prototype that uses a generator to develop the voltage necessary so as to avoid the need for batteries.

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While it is common practice to see making and rapid prototyping incorporated into freshman introductory classes and senior capstone experiences, it is less common to see it in traditionally lecture based/theoretical classes or those taught in the sophomore or junior year.  This project is best implemented in a junior level fluid mechanics class, though it could be used in a freshman introductory class as well.  The project highlights curiosity, connections, and creating value while increasing student confidence and experience with making technology and rapid prototyping.  The project is designed for students in teams of 3-4 to complete over the course of 3-4 weeks, and requires 3 class periods over this period to deploy. 

The project is broken into two parts: Part 1 is the prototyping phase (a hands-on design exercise) and Part 2 is a product development exercise.

In Part 1, students in the class design and prototype a small consumer device that 

1) must attach to a standard faucet,
2) must interface with an instructor-provided generator;
3) can use any prototyping method, including 3D printing, for blades or an impeller, and can use designs from online CAD drawing libraries such as GitHub;
4) must have CAD-drawn parts and employ a manufacturing method other than 3D printing for other parts (housing, attachment, etc.), such as wood, plastic, or metal laser cutting, machine or wood shop methods, and/or a water jet.  

The device will be tested to measure the voltage generated.  

The device should be developed as if it was intended to be a novelty consumer product.  In Part 2, questions students will have to answer include:  How much did it cost to make (bill of materials)?  If you included engineering, shipping, marketing, distribution, service, and profit, how much would it retail for?  Students will have to identify and consider any unexpected or better opportunities than a kitchen sink or outdoor hose to use the product or a similar product.  For example, in what other settings could a generator be used to extract useful energy that is currently wasted?  Finally, if implemented in a Fluid Mechanics class, what principles from your fluid mechanics class were demonstrated by your product's performance?

Students prepare a document including a brief introduction, a summary of the design and rapid prototyping process, photos of the device, machine shop and makerspace technologies and techniques used, testing results, opportunity and market identification (and answers to questions above), and finally recommendations for improvements.