An assistive device is a tool that helps a person do a task more safely, independently, or comfortably. In this project, students invent a low-cost device for a real disability or accessibility challenge, such as opening jars, fastening buttons, reaching objects, or holding a pencil. The goal is not to make a complicated gadget, but to solve a real problem with empathy, evidence, and careful testing.
A strong project begins by learning from the person who faces the challenge or by researching reliable information about the need.
Key Facts
- Design goal = user need + task + success measure.
- Cost per device = total material cost ÷ number of devices built.
- Mechanical advantage = output force ÷ input force.
- Percent improvement = ((new result - old result) ÷ old result) × 100%.
- A useful prototype should be safe, affordable, testable, and easy to improve.
- Iteration means build, test, learn, redesign, and test again.
Vocabulary
- Assistive device
- An assistive device is a tool, object, or technology that helps a person complete a task or participate more independently.
- Empathy interview
- An empathy interview is a respectful conversation used to learn about a user's needs, frustrations, routines, and preferences.
- Prototype
- A prototype is an early version of a design built to test an idea before making a final product.
- Constraint
- A constraint is a limit on the design, such as cost, time, size, weight, safety, or available materials.
- Iteration
- Iteration is the process of improving a design through repeated testing and redesign.
Common Mistakes to Avoid
- Designing before understanding the user, because a device that looks clever may not solve the person's actual problem.
- Ignoring safety and comfort, because sharp edges, weak joints, or awkward grips can make an assistive device harder or riskier to use.
- Testing only once, because one trial does not show whether the device works reliably for different attempts or conditions.
- Choosing expensive or rare materials, because a low-cost assistive device should be practical to repair, replace, and share.
Practice Questions
- 1 A student builds a jar opener prototype using 1.40 of cardboard, and $0.90 of glue and tape. What is the total material cost of one prototype?
- 2 Before using a reach extender, a user can pick up 6 objects from the floor in 2 minutes. With the prototype, the user can pick up 15 objects in 2 minutes. What is the percent improvement?
- 3 A button hook prototype works quickly, but the user says the handle is uncomfortable after one minute. Explain what the design team should change next and what evidence they should collect during the next test.