uHeartrate stands for ubiquitous heart rate which means you can monitor your heart rate with the application whenever wherever you want! All you need to do is launch the application and choose measurement modality you want. It provides two modality of measurement of your heart rate.
- using accelerometer
As you know, iPhone has a 3-axis accelerometer. Actually, we proved that the sensitivity of the accelerometer is high enough to measure tiny vibration caused by every heart pumping in the our previous study.
- using camera
The other one is to use iPhone camera. Every heart pumping causes local blood volume changes in the artery and it propagates toward whole body. When it reaches your finger, the application measure the blood volume changes in your finger with the flash. The core principle is that the light from the flash penetrates your finger or is reflected by the tissues in the finger. The camera is measuring the intensity of reflected light. However, when the blood volume changes reach in your finger, the intensity of reflected light decrease. We can measure heart rate with the decreasing interval.
* Video links
http://abrc.snu.ac.kr/uheartrate/video.html