I pasted in my HOWTO for building a arphid cloner, and some tips for getting close enough to people to read and write their tags. I put my own cloner in the pocket of my vintage black leather motocross jacket with the armored pockets and left for school. I managed to clone six tags between home and Chavez High.
It was war they wanted. It was war they'd get.
#
If you ever decide to do something as stupid as build an automatic terrorism detector, here's a math lesson you need to learn first. It's called "the paradox of the false positive," and it's a doozy.
Say you have a new disease, called Super-AIDS. Only one in a million people gets Super-AIDS. You develop a test for Super-AIDS that's 99 percent accurate. I mean, 99 percent of the time, it gives the correct result -- true if the subject is infected, and false if the subject is healthy. You give the test to a million people.
One in a million people have Super-AIDS. One in a hundred people that you test will generate a "false positive" -- the test will say he has Super-AIDS even though he doesn't. That's what "99 percent accurate" means: one percent wrong.
What's one percent of one million?
1,000,000/100 = 10,000
One in a million people has Super-AIDS. If you test a million random people, you'll probably only find one case of real Super-AIDS. But your test won't identify one person as having Super-AIDS. It will identify 10,000 people as having it.
Your 99 percent accurate test will perform with 99.99 percent inaccuracy.