Senior Capstone

"Design a lightweight product that can consistently and effectively charge devices when backpacking in places where solar power is less reliable."

The number of thru-hikers that complete the 2,000 miles of the Appalachian Trail has grown exponentially since the 1980s, reporting record numbers on an annual basis. A similar trend has been happening on other National Scenic Trails like the the Continental Divide Trail and the Pacific Crest Trail.

In the last ten years, technology has also grown in an exponential fashion. Modern hikers now have the ability to navigate via a variety of apps on their phone, but keeping a phone and other devices charged is not always easy when thru-hiking in the wild.

A power bank or solar panel are the only two mainstream methods to charge a phone in the wild. Both have significant disadvantages when trying to pack light and travel far. Yet nothing has been done to improve this user experience.

Kinetics

Water

Wind

After conducting research I determined that water would be the best natural resource to utilize when charging devices on the trail. Hikers will most often set up camp by running water so that they can cook dinner and fill up for the next day. This opens the door to a product that can be placed in the water and charge overnight with minimal hassle. When used correctly, water is 90% efficient, which outperforms a 30% efficient wind turbine. A kinetic object that charges as you move could be a viable option in the future, however based on my research, the technology is not quite advanced enough for the problem I tried to solve with this project.

There are several competitors I came across in this portable energy space. However, they are not sold by any mainstream outdoor recreation businesses, and do not seem to be in high demand for ultralight thru-hiking. After creating a competitive set it was obvious they all have some incredibly large downsides. They are either too heavy, too inefficient, or just too expensive for what you are getting.

One of the most important steps in my capstone was gathering user data. I started by creating a user persona of the market I was trying to target. Then I sampled one-hundred hiking enthusiasts, using questions I generated to gain a statistical understanding of the user.

“Hi, my name is Mark! I love to hike on the weekends and go backpacking at least twice a year in my home state of Utah. One of my greatest accomplishments was thru-hiking the Appalachian Trail. This year I plan to hike the entire Pacific Crest Trail as well. I consider myself an experienced backpacker and always strive to pack light and travel fast. Unlike the Appalachian Trail, the Pacific Crest Trail is not as well marked, so I will be using a GPS phone app for this thru-hike.”

After establishing that there is, in fact, a need for a product like this I could then move into determining the best turbine, motor, and electrical components for the design.

The most prevalent types of water turbines are francis, pelton, or kaplan. After expanding my knowledge about the three types, it was clear that a kaplan turbine would be best for the product, given the minimal head/flow rate needed to make it run, as shown in the graph.

It was necessary to choose a proper motor for the design to guide the overall size of the product. After running multiple tests it was clear that the micro motor on the far left would be best. Not only is it smaller than the others. It also has mini gears in the top portion, allowing it to generate a higher voltage at the same RPM.

After testing countless circuit configurations I was finally able to create a working system for this product. Using this I was able to effectively charge an 18650 battery at 5v with relatively low RPM.

Using wax and plastic housing I was able to conduct a test on the viable waterproofness of the motor. Surprisingly all three tests continued to run for an entire week, meaning that they could be fully submerged and work flawlessly for at least 7,000,000 rotations.

Ideation Sketching

Functional Prototyping

Branding

Final Design

Charging and Portability