This heart rate monitor application uses the iPhone’s microphone to “listen” and measure your heart beat. As the image shows, you can use the phone directly on your (bare) chest, or more conveniently under your jaw, with a headphone cable microphone. It is said to work best with the new iPhone 3G. Users of older models should always use the headphone microphone. (video in the full post)
iPhone App – Heart Monitor from John Ballinger on Vimeo.