title: Android / iOS API access to Bluetooth heart-rate monitors
body: <p>I'm looking to write some Android or iOS applications to access a Bluetooth heart-rate monitor. There are currently some apps available like Android's "Heart Rate Monitor" that connect to heart-rate monitors like the <a href="http://www.zephyr-technology.com/consumer-hxm" rel="nofollow">Zephyr HxM</a>, so I know it can be done. </p>
  
  <p>What is the programming API like? If I write an app, would it be able to connect to any heart-rate device? Or would I have to follow some application-layer protocol from the device manufacturer and read and process Bluetooth packets?</p>