Pretty Slick Technology

During lunch today, I took a few minutes to play 'Phoenix Wright: Ace Attourney' on my Nintendo DS. The game follows a lawyer through several involved cases.

On the current case, you are given a bottle of fingerprinting dust. You apply the dust by tapping the lower screen with the stylus. This in itself is impressive, the touch screen is very responsive.

But the truly slick part, is how you remove the excess dust. The game tells you to just "blow". This stumped me at first. I thought, "what, I'm just supposed to blow air at it?" I tried all the other buttons, looking for a "blow air" button, but there was none to be found. So I took a breath, and blew... and the screen responded! Little pixular dust particles flew away as if I had blown them with my breath.

At first I thought it might be sound, but it only worked if I blew directly into the little microphone slot on the bottom right. If I covered up the slot, or I blew away from the slot, it didn't work. My best guess is the DS hardware listens for static(blowing on a microphone), and reports it to the game. Then the game can interpret the static how it sees fit.