1. Integrated GPS and Shock Collar Housing Nathanael Skiver, Brent Berg, Blaine Hutchinson, and Ryan Pedersen Advised by: Dr. Peter Gorder and Dr. Valmiki Sooklal IntroductionFinal Design Testing Conceptual Design Process Next Steps The first step in the design process was to determine if there were similar products on the market, and how would our design compare to these products. The team found that there were few products that incorporated the use of a GPS to trigger a shock to a dog. From there, the team brainstormed on the following design aspects: Overall appearance of the design Material Prototyping method Waterproofing method After brainstorming, the team decided that the box prototype should be made using a 3D printer. This would sufficiently simulate an injection molded part, but would be much more cost effective. It was decided that the case should be made waterproof by use of a rubber gasket. Again, this is an extremely cost effective solution and would be very easy to implement. Taking bits and pieces from the team members’ initial ideas, as well as aesthetic cues from similar GPS/shock collar units currently on the market, the team arrived at the final design for the two housings, shown below. In order to ensure that these designs met the requirements of the customer, these prototypes needed to be tested, specifically to meet the criteria that the cases be waterproof and rugged. The team decided that the case would be sufficiently waterproof if less than 0.2 ounces of water leaked into the case while submerged at a depth of 1 foot for a duration of 5 minutes. The case would be sufficiently durable if, during a finite element analysis (FEA), the von Mises stress did not exceed half of the yield stress of ABS plastic with a 200 lb static load applied to the largest face, giving a factor of safety of at least 2. Foxhunting is a sport that utilizes a pack of dogs directed by individuals on horseback to hunt foxes. The process as it is currently is very challenging, as dogs need to be whipped by their horseback handlers to be given directions. In order to ease the burden on the handlers, a custom shock collar was developed that could be triggered both remotely and geologically by use of a global position system (GPS). Essentially, if a dog wearing the GPS/shock collar assembly strayed too far from the handler, the GPS would send a signal to the shock collar, shocking the dog and prompting it to return within the desired range of the handler. Team Foxhunt was given the task to create two connectable housing units that would protect an off-the-shelf global positioning system (GPS) unit and a custom shock collar motherboard. The cases needed to be: Waterproof Rugged and durable Aesthetic Results After testing using these criteria as guidelines, we arrived at the following results: Finite Element Analysis Test Number Wall Thickness (in) Max Stress (ksi) Yield Stress (ksi) Factor of Safety 10.1254.9965.851.17 20.1554.2475.851.38 30.1753.075.851.91 40.2052.2115.852.65 Waterproof Testing With a wall thickness of 0.205 inches, the factor of safety found from FEA was found to be 2.65, so that is the thickness used in both the GPS and shock collar housings. After the waterproof testing, it was determined that the shocker case did meet the design criteria, resulting in a pass, while the GPS case did not. It turned out that there was an error in the 3D printing process while the GPS case was being printed, and several layers of plastic were missing. This resulted in a noticeable hole that went through the entire wall thickness. Test SpecimenTime Submerged Mass of water gained (Average) Pass or Fail GPS Case5 mins0.225 ouncesFail Shocker Case5 mins<0.1 ouncesPass Though the first prototypes performed well in the initial testing, there are several changes that could be made to the design to help them perform better. Properly slice the 3D CAD model so that 3D printing is more accurate Machine box out of a solid block of ABS plastic to avoid the 3D printer all together Edit gasket material from a hard rubber to a compressible rubber foam Special Thanks To: Josh Burns, the Bachelor’s of Innovation team, Dr. Bruce Johnson, and Ron Wilkins