I tend to be pretty careful when I'm using an ATM, checking that nobody can see my fingers as I enter my PIN code. But now scientists have revealed a way to tell which buttons you pushed, even after you've left the machine cash in hand.
Researchers at the University of California in San Diego recently showed how they could "read" the buttons of an ATM keypad with an infra-red camera, revealing which buttons had recently been pressed. As you can see in the picture, the recently pushed buttons have a distinctive red glow in the middle that tells all.
That's sounds worrying, but before you start carrying ice cubes with you to the ATM consider the hurdles a potential PIN code thief will face. The camera used by the researchers costs about $18,000, and apparently a cheaper model won't do. So your thief will need to have deep pockets. Another problem is that the camera method only works on ATMs with plastic buttons, because the metal type tend to throw off too much stray heat. Finally, the picture tells you which buttons were pressed, but not the order they were pressed in.
Considering all of these issues, I guess I'm not too worried. Still, I'll try to keep a eye out for any well dressed but shifty looking photographers carrying bulky photo gear, who happen to be standing in line behind me.