User:Medelen8/ENES100/Smart Shoe Design

Problem Statement
The purpose of this project is to design a small, portable device that accurately senses and displays a person's vertical jump height.

Requirements for each element or component derived from system level goals and requirements
According to prior documentation, there is no Conceive report since NIKE has already developed a shoe (Hyperdunk) that also measures your vertical height. However, there are requirements that we aimed for in the four weeks. They include:
 * 1) Getting the device as accurate as possible, with a low percent error.
 * 2) Keeping the device small and compact (must be able to fit on your shoe).
 * 3) Adding a case to the device so that the parts will not wear out after being tested a bunch of times.
 * 4) Creating designs for final product, these include case, price, and types of arduinos.

Alternatives in design
First, we built the device with a standard Arduino Uno, prototype shield, and an ADXL335 accelerometer. Because this design is too big, an Arduino Nano will be implemented soon.

The initial design
Here is our code that we used for the Arduino:.

To obtain our height equation, we solved for y, t=sqrt(2y/g). Also, we multiplied by 3.281 to convert meters into feet, and added .25 inches because the device was never placed on the ground when jumping; it was always placed at the top of a shoe.

Experimental prototypes and testing conducted during design
To test the accuracy of our product, we conducted trial tests. First, we jumped at 17 inches, and then 20 inches, and recorded our results. To make sure we jumped at an accurate height, we used a chair aligned with a ruler at 17 and 20 inches. For both times, the device was off by .1 inch or .2 inch 3/10 times, and therefore was accurate 8/10 times.

Appropriate optimization in the presence of constraints
The biggest problem we had was getting the sensitivity of the Arduino in place. To fix this, we did a lot of testing to get perfect numbers. As you can see in our code, the sensitivity measurements we used were 100 and 160.

Technical and scientific knowledge
Before we began the project, we took a look at it from a physical point of view. What relationships could be found, how do people actually "jump", and how can you measure the height efficiently? We then stumbled upon basic physics equations, and narrowed it down to the equation t=sqrt(2y/g). This formula allowed us to find the height of jump simply from the time spent in the air. However, the "t" represented by the equation would only represent the falling part of the jump, so we substituted the value (s/2) for t, where s is seconds spend in the air.

Creativity, problem solving, and group decision-making
As a group, we had to make many decisions, which slightly altered the path we took to complete the project. First, we picked apart the code left to us by the previous group, and modified it to fit the constraints assigned to our project. The first thing we decided to do was to add a casing around the Arduino device, so that it could be safely secured to a shoe. Secondly, we altered numerical values in the code to make the shoe more or less sensitive, depending on the situtation.

Prior work in the field, standardization and reuse of designs (including reverse engineering and redesign)
To move on in our project, we studied the code left to us by the previous group, reusing the general idea. We discovered that the formula we derived as a group to measure the height was very similar to the existing program.

Performance, life cycle cost and value
In order to ensure performance and help with the life of the arduino it will be encased inside a plastic water proof "shield" so that the elements do not come into direct contact with the arduino. If it is used properly the product should last 2-3 years because it is not coming into direct contact with anything and should only be used for regular jumps while attached to a shoe. The estimated value of the product is 50 dollars, we got this number because an arduino nano is $30, an accelerometer is $5, and a RF (range frequency) link is $5. We added $10 for profit and labor etc.

Aesthetics and human factors
The final clip will be small for light weight and so that its not in the way too much. The product will be simple and safe to use, just a plastic case the user clips onto the side of their shoe and a small switch that is pressed to turn it on.

Implementation, verification, test and environmental sustainability
When the program is loaded on to the arduino nano, testing will be necessary to make sure the jump height is correct. When the testing is taking place it is important that it is a real jump to allow for proper fall time in the coding as well as a known height of the jump. We currently are over 80% accurate to the hundreds decimal place. The environment this is designed for is a flat dry surface such as a basketball court or a running track. If the device is used properly then it should function properly for about 2-3 years.

Maintainability, reliability, and safety
In order to maintain the product the user will not have to do a lot of things besides making sure he does not misuse it by, for example jumping off high ledges to find his/her height (which wont work), or attaching the device to anything besides the shoe for any measurements. This product is reliable for the intended purpose of recording your jump heights to help see a trend in progress or other trends. As the product approaches over 80% accuracy people will be able to tell if their practice exercises are helping them jump higher. As far as safety is concerned there is nothing really dangerous about the product besides the needle that goes through the shoe and clips into the case, but as long as the user properly clips it in then there is no risk of being punctured even if the needle were to somehow become un-clipped.

Robustness, evolution, product improvement and retirement
As for now there are no plans to add on or evolve this product. Measuring and recording jump height was the purpose of the project which was met along with time in air being displayed. As the smart jump becomes more popular perhaps different methods of securing the device to ones shoe would be good for meeting the needs of particular individuals. For retirement the case is plastic and can be thrown away, to properly dispose the arduino, accelerometer, rf link, and batteries you can recycle it under the computer category or even send it away online to a site that pays for old micro controllers.