Instant heart rate is a heart rate monitor for Android smartphones that uses the phones built in camera to measure your heart rate.
This application measures oxygen saturation changes in your blood. On every heart beat your blood becomes more oxygen rich which causes a slight change in the color of your skin; the camera in your phone tracks that change and calculates your heart rate. It works similar to a medical pulse oximeter but without a dedicated light source.
Press your left index finger gently over the camera. Hold it steady for at least 6 seconds. Your current heart rate will be shown on the display.
It's important that you use this application with good lightning. For best results turn the back of your mobile towards the sun or a lamp.
To try it go to Androd Market on you mobile and search for "Instant Heart Rate"
This application is been made as a part of a study of using sensors built into mobile phones for measuring biological signals. Check it out... it's FREE!