I was able to get everything I needed for this project for under about $20, so this project is really accessible to anyone who wants to explore this fascinating topic. It would make a great science fair project, or could just be a fun project.
You will need:
I got mine from amazon for about $5 (not including shipping). It works great and at that price, how could I pass it up. I'll leave a link to where you can get one. If you already have a cam you want to use, make sure it has 1.7 megapixel resolution or better (otherwise the small flashes of light will not be visible), but other than that almost any web cam will work. Mine had a CMOS visual sensor in it, but CCD will also work just as well. Before you buy your webcam make sure it is compatible with your computer and operating system.
You can find these at pretty much any home improvement store. To make sure it is the kind that actually contains Americium check the label on the back. It usually says right on it that it contains "0.9 microcuries of Americium 241 a radioactive element..." but as long as it says it is an ionization type smoke detector it should work. These are $10-$15 at home.
-Video capture software:
My PC didn't come loaded with a capture software on it compatible with my webcam, so I downloaded Debut Video Capture software. I had the trial run for a while before it devolved to the freeware, for this project the free version will be just fine.
(you will also need a computer but I am guessing you already have one since you are reading this)
this is not very important because everything should just fit back in the webcam housing, but I made a case out of a margarine container to make it look better.