https://play.google.com/store/apps/details?id=com.rs.bitcoin.machine&hl=en
This app pays with SATOSHIS. It won't drain you phone battery, it won't make any noise. One issus I encountered when I reseted my phone and I reinstalled the APP all the SATOSHI EARNED WERE GONE, I couldn't make any withdrawal, Some one I know did not have any problems withdrawing her money. Give it a try.