Find a heart rate monitor on Android
For android phone, it's hard to find a cheap heart rate belt monitor. Some cheap heart rate monitors supprt only ANT+ protocol like
Xplova XA-HR2 or
PAPAGO! ANT+, you need a GPS running watch to conntect with. For smart phones, we can only use a heart rate monitor that supports bluetooth. However, the most of bluetooth heart rate monitors are using bluetooth 4.0 protocol.
Until versoin 4.3, Android supports bluettoth 4.0 and BLE(bluetooth low energy). Upgrading my New HTC One to 4.3, I bought PAFERS. For now, most of running apps don't support BLE heart rate monitor. I finally found a compatible android app BLE Heart Rate Monitor. Although it's not offical support android by Pafers yet, but it works. :)