Do my homework

I have a major assignment coming up and I need some ideas. I have to do a "description of mechanism" for some device, and I have no idea what to write about. It has to be an object with two different parts, each of which has to have 2 sub-parts.

That's not a very helpful description, which is why I'm having trouble coming up with an idea for it. The best I have so far is a can opener, and that's boring and will likely be done by somebody else anyway.

I'm not really looking forward to this assignment. I have to describe every aspect of this object so that somebody who's never seen one before can just read my document and understand what it is and what it does. Time's running out and the harder I try to decide what to write about, the less I manage to get done.

Update from the Tim Hortons Inspiration Journal:

I went to Tim's before class today, and while I was there I started sketching ideas for the device I'm going to make up for my proposal. I had a bit of trouble figuring out how it should take input, and I came to the conclusion that it would either need a scrolling wheel or up and down buttons for selecting a route, and a toggle button for changing the direction. I wanted to put a keypad on it, but there's no way I could do that and still make it small enough for the average person to want to carry around.

I had a good idea of limiting the routes you can select to the ones that go by the stop you're closest to, but I figure that setting up a system that reports that info to the device would be more work than I could possibly expect for a pilot project. Every stop would need a transponder of some type, and every device would need a way to process that information. Having a processor in the device would probably kill the batter life and make it more complex than it needs to be. Right now it's about as complicated as a calculator and has storage for all the valid routes and their directions, information that it scrolls through with either the buttons or the wheel, depending on which input I decide to go with.

I got a lot of work done on it, and I think I can start to focus on the actual writing soon.