[Nyle]

A lot of it depends on what you want to get out of the prototype. If you just want to demonstrate some mechanical concept or have a visual aid to help you think through the details, something as simple as cardboard and tape can be a valuable prototype. On the other hand, you want to test whether material A is able to grip cans effectively, or if some certain springs will be strong enough, you'll want to make the prototype as close to a final mechanism as you can within your team's budgetary and time limitations. Your goal with prototyping should be to get it to a point where you can either find out how your current design fails (and then figure out how to fix it, of course) or can feel confident in moving on to a more full prototype or final mechanism. If your team doesn't use CAD when designing your robot, consider learning it over the summer too. A CAD model of a mechanism serves as a great sort of prototype in itself, allowing you to work through all the details and get a look at how it will move before you start spending any time or money making physical prototypes.