Table 7 is linked below and is a bill of materials for the prototype, including stock material and fasteners. The components are organized by subteam and all sources for pricing may be found in Budget References under the corresponding numbers. The team made an effort to minimize price without sacrificing quality. The estimated total cost of the prototype is currently $1,327.07. This price may fluctuate as other systems are added and parts are improved, but it is estimated to stay within the $1,400-1,600 range. This price successfully satisfies the metric for the cost to not exceed $2,500 (Specification 1). Since the team requires extra items for testing, such as the wheelchair base model and independent control systems, additional parts have been purchased to allow team members to build mini prototypes and conduct tests in various locations. The additional purchases are listed in Table 8 (linked below), with pricing references shown under corresponding numbers in the Budget Resources. Currently, the total extra expenses sum to $245.25, which is expected to increase depending on whether team members can work in the same locations with the same parts in the spring or if we will need to order extra components.
Once the components have been purchased for the prototype, the team will need time, space, and tools to assemble and store the prototype. The spaces used thus far have been team member’s homes both on and off campus. The team intends to use Leopard Works room 006 to work together to assemble the prototype. Additionally, the team will be manufacturing components in the machine shop and with 3-D printers. If this is not possible, the team will continue to test subsystems remotely and find another way to assemble a prototype. A series of experimental tests will be conducted to determine the strengths and weaknesses of the prototype. The tests will assess weight, speed, maneuverability, range, and response to user input. They will initially be conducted using an object, such as a sack of potatoes, to ensure that the prototype is safe to use. Once the prototype is confirmed to be safe enough for human use and the risk of injury is greatly reduced, members of the team will begin testing the device by using it themselves. The tests will take place on various straightaways, inclines, and declines on campus. These locations will include ramps to enter buildings, hallways, sidewalks outside of Acopian Engineering Center, the hills by Acopian Engineering Center, Sullivan Street, Hamilton Street, and more. Outdoor testing will be dependent on the weather conditions. The team will need to physically transport the prototype to these locations. The results of the tests will inform how the team moves forward in the design process.
Additionally, the prototype will be further refined by the results of the surveys and interviews with people who use wheelchairs and healthcare professionals conducted in accordance with IRB guidelines. It is important to get input directly from the target audience to ensure that their needs are met. This is discussed further in Stakeholders of External Partnerships.
The testing and feedback from the surveys and interviews is expected to result in multiple prototype iterations. As a result, the bill of materials, additional expenses, and total budget for the team is anticipated to increase. However, the team intends to limit the increase in the cost of the prototype while maintaining product quality in accordance with the design objectives.