By Andrew Liszewski
Originally rejected from the iTunes App Store over a year and a half ago because the developers had to 'hack' their way into accessing the iPhone 4's camera, Rafael Lozano-Hemmer's Pulse Phone app was only recently finally approved after Apple loosened their restrictions a few months ago. Now while it's not the first app on the market to detect a user's pulse, most of the other options out there use the iPhone's microphone to listen for sound like a stethoscope, and since the iPhone 4 isn't purpose built for that application, they rarely work that well.
Pulse Phone however has the user place the tip of their index finger over the iPhone 4's flash and camera lens, which illuminates the finger and allows the app to detect subtle color and brightness changes as blood pulses through its veins. The app works on older, flashless, versions of the iPhone or iPod Touch, but you'll need to use it in a well it area for it to be effective. But thanks to the iPhone 4's flash, you can even use the app in complete darkness. It's brilliantly simple and clever in my opinion, and while there's a big warning when you first load it up that it shouldn't be used for medical purposes, from my own testing it's pretty darn accurate. Pulse Phone is available as of last week on the iTunes App Store for just $1.99, making it an inexpensive yet very impressive party trick.