calculus problem: motion

I've got another problem in my calculus class. This particular project doesn't include *any* calculus whatsoever. In this case I'm trying to design a contraption that raises the american flag so it doesn't get in the way of my math teacher's head when he walks near it. I've already come up with a goofy contraption that you can strap to his body so that when he gets closer to it the flag gradually raises...it works with ropes and pulleys but i was wondering if there was any method to detect when he is closer, such as something he can step on, that will activate an electric motor to raise the flag.

Did he offer you extra credit to do this? Or are you just bored?

we had to choose a problem that deals with math/science, and I chose to come up with a creative way to move the flag out of the way as he walks past it.

Piezzoelectrics could be useful. They convert pressure to electricity and vice-versa.

look for infared sensors for something like a desk/wall area were he walks by

or a pressure sensor you could put in a mat

look around for this: http://www.robotstore.com/search.asp...d=muscle+wires

they use a small amount of electricity for alot of linear motion... and they can be used for millions of cycles each... they were used in the mars pathfinder project (http://www.robotstore.com/download/MW_on_Mars.pdf)

those are cool links. the problem is i have to actually make this.

just put a little electricity through them and you have linear motion... it's not too hard to make, unless by make you mean from complete scratch, which would mean making the muscle wires, but then you couldn't use a pulley system either...

You need an electronic eye near the flag. When he steps in the way of the beam - similar to the beam at the bottom of automatic garage doors - the circuit is broken which fires off a motor that raises the flag.

Current must pass through both the sender and the receiver of the beam. If the receiver does not see the beam - the current is directed back to the motor. Attach a pulley to the motor and attach a rope to the flag which goes around the pulley. When the pulley turns - the flag raises and lowers. When he steps out of the beam - the flag will also lower.

Step 1) Get some claymors
Step 2) Set them up in front of flag
Step 3) Make sure to inform the teacher so he doesn't walk in the mined area.

Ok that was a joke

You can get components that can tell you how far away something is for a few bucks.