Heart Rate Monitor

Android based heart rate monitor which uses the camera and its flash to determine the users heart rate in beats per minute using the Android device camera image recognition technology.

How To Use:

All you have to do is open the Heart Rate Monitor App and then hold the tip of your index finger over the camera lens of your phone. The entire camera preview image should be red with a lighter area where the tip of your finger is touching. Do not press too hard or you will cut off circulation which will result in an inaccurate reading.

After a second or two, you should see the Heart icon on the top of the screen start to beat when it senses a heart beat. After ten seconds it will compute your heart rate and update the number next to the Heart icon. It'll take between ten and thirty seconds to get a fairly accurate heart rate.

Typical heart rate while resting: 60-80 beats per minute

Typical maximum heart rate: 220 - your age (e.g. 190 for 30 year old)

Typical target heart rate for physical exercise: Max heart rate x (0.65 or 0.85) i.e 65% to 85% of Max Heart Rate
(e.g. For a 30 year old with max heart rate of 190, Target Heart Rate while exercising will be 123 to 162 beats per minute.

Image Recognition Algorithm Details:

The Heart Rate Monitor App uses the PreviewCallback mechanism to grab the latest image from the preview frame. It then processes the YUV420SP data and pulls out all the red pixel values.

It uses data smoothing in a Integer array to figure out the average red pixel value in the image. Once it figures out the average it determines a heart beat when the average red pixel value in the latest image is greater than the smoothed average.

The Heart Rate Monitor App will collect data in ten second chunks and add the beats per minute to another Integer array which is used to smooth the beats per minute data.