title: Is it possible to get PPG(Photoplethysmogram) data from a smart watch via android?
body: <p>I want to develop a health care app using Android smart watch devices that have an optical heart rate sensor.  Examples of such devices are: Samsung gear live, Moto360, LG G watch R, etc.</p>
  
  <p>To do this, I need the raw PPG signal data from those devices, but I found that the Android API only supports heart rate data by BPM unit.</p>
  
  <p>Does anyone know if the raw signal data is accessible, and if so, how do I get access to that data?</p>