Instant Heart Rate is the best and most accurate heart rate monitor application in the android market. Instant Heart Rate app measures your heart rate by analyzing blood flow on the tip of your finger. So this is a cardiograph on your android device. Carry our instant heart rate monitor with you and check your heart rate anytime, anywhere, **** IMPORTANT **** For correct reading, hold your index finger on the camera lens steadily & lightly for the whole heart rate measuring process.HOW TO USE ? 1. Lightly place the tip of your left / right hand index finger on the camera lens FEATURES 1. Measure your heart rate by using camera on your phone.