Formable Mouse

Overview

Our Formable Mouse (Patent Pending: Application # 16/853,506) was designed to solve the problem that current mice on the market are too rigidly defined in shape. This rigidity leads to decreased comfort for end users as well as increased risk of injury. Previously, mouse designers were highly limited in that they needed to create a product for a majority of the population instead of the individual; we avoided this problem by creating a way for the user to mold the exterior shell of the mouse to their hand, increasing comfort and potentially decreasing the risk of injury to our customers. 

This solution was achieved by using two types of thermoplastic to create a single outer shell of the mouse. Upon boiling the design, one thermoplastic becomes soft enough to mold to a person’s hand, while the other remains rigid enough to allow the molded thermoplastic to interface with the rest of the components of the mouse. This was our goal from the inception of the project. 

Upon conducting market analysis and interviews with potential customers, we determined that gamers would be the largest market we could hit with such a design. We continued to conduct prototype interviews with our target market to ensure that the product we were designing would bring value to the industry. For prototyping, we used 3D printing and hand molding to create our product. The design was also tested at every level of iteration (of which there were over a dozen) to ensure its quality. It is our intention to bring the product to a design point that can be easily injection molded so that we can further the project and hopefully bring it to market by the year’s end. 

Considering that we are a self-made project, we had no former client except for ourselves, Mouse Tailor Group LLC, which was created for the purpose of developing our patent and eventually bringing the product to market. However, Bud Rockhill filled the role of both “client” and business advisor for the sake of Senior Design.

Our preliminary designs were created to try to encapsulate as many possible solutions to the problem we had previously established while also following constraints that we established to limit the number of possible designs. Two of the constraints that we established were creating a consistent, high level molding process for the mouse as well as a volumetric constraint for each mouse. 

We established four, varying preliminary designs which complied with our constraints while following completely different design mentalities. The first design, called the single shell design, consisted of three components: the moldable shell, the shell anchors and the body. The moldable shell of the mouse is a pre-shaped thermoplastic that, when sufficiently heated, can be molded to interlock with the base with the anchors. The heating also allows for molding to the user’s hand. Our second design concept, titled the entire boil, was based around the idea of making the molding process as easy as possible for the user. This design had all the components of the formable mouse preassembled and only required that the user boil, mold, then use the final product. Our third concept, called the pockets design, was based around the idea of optimizing design such that we only applied moldable thermoplastic to areas that the human hand came in contact with. Pockets could hold heated thermoplastic and allow for the shape to change in the specific areas. Our last concept, the double shell design, was composed of two interlocking shells: one which bonded to the thermoplastic and one shell that held the electrical components of the mouse. With the preliminary designs established, we set up a system to rank each design. 

We used a design matrix to determine which of our concepts would be selected for final design. The design matrix showed the selection criteria, weight for each criteria which we selected according to the customer needs we established, the rating we assigned to each preliminary design per selection criteria, and a final rank for each. The criteria for selection were: cost, weight, feasibility, ease of use, looks, and added comfort. Using the design matrix, we determined that the single shell (concept 1) and the double shell (concept 4) were equally ranked. With this as the final step, we realized that instead of just expanding on one preliminary design, we could take components that worked from all the concepts to create a final product. 

  We applied engineering analysis and models to determine whether a mouse we created could perform according to its environment. Our engineering models focused on two components: mechanics of materials and heat transfer. Mechanics of materials was applied directly to the ability to repeatedly click the main two buttons for a large number of cycles without failure. Originally, our design had snap hooks in addition to the main clicking buttons, but we eventually steered our design away from snap hooks which meant there was no need for additional solid mechanics analysis. This was because the snap hooks failed too easily, leading to a frail product that couldn’t attach very well. With solid mechanics addressed, we analyzed the effects that heat flow had on our mouse.  We set up two scenarios which could potentially be used to heat up the mouse and used simulation to produce values that we could test. The two different scenarios were heating the mouse from a constant boil and heating the mouse in water that was boiling but was put into a bowl that is cooling in the room temperature air. We also did simulations for the thermoshell in a car on a warm summer’s day in order to understand if there could be unwanted melting. Most of our simulations were either done in SolidWorks Simulation or MATLAB. 

In conjunction with engineering models, we also established a failure mode and effects analysis (FMEA) to focus on certain aspects of the mouse which may fail, but are hard to analyze from a technical perspective. The FMEA generated many possible failure modes, but the most troubling failure mode that we encountered was the possibility that water from the molding process could damage the circuitry in the mouse base if the shell was not dried off before attaching the thermoplastic outer shell to the base. We established various testing procedures to ensure that this (and many other risks) were improbable.

Additionally, customer interviews were done with multiple iterations in order to gain a better perspective into what the design could improve upon. These interviews were done by taking potential customers through the molding process and gathering their opinion about how to improve the design. This direct interaction greatly helped the team identify areas to improve.

The engineering analysis and FMEA that we performed gave us two pieces of crucial information: whether or not it was possible for our product to work and base marks that real world experiments should trend toward. We took the values that we collected from our engineering analysis and established tests which best replicated the scenarios used in the engineering analysis and FMEA. We primarily tested means by which we could color the moldable plastic, how screw position impacts the mounting of the base, remoldability of the polycaprolactone from a thermal perspective, PCB water failure in cases where user forget to wipe off the mouse base, a visual observation based study of how individuals perform with the mouse, observations of users with their mouse, and possible solutions for comfort testing. 

Through the engineering analysis, FMEA, and testing we were able to modify and improve the design through multiple rounds of iterations. The most critical contributors to modifying the design was customer interviews and testing. The models and FMEA helped modify initially, but these interactions were the most critical. The direct interactions with customers made customer interviews beneficial, and iterative testing allowed for the design to readily be improved. Design experts were also communicated with in order to better understand how to improve the design and think about the design from the customer’s perspective.