Android: How to "Voice Detecting" to Voice Recorder

I've done voice recording and playing following this link:

Record audio and play the recorded audio

I need a change in it. It is recording and playing on button click. Rather I want to a background service or whatever that continuously "listening mic", if it detects some voice then it should record it (let say max length of recording is 1 min) and on voice recording finishing (eit开发者_运维百科her there is no input or 1 min recording completes) then it should play it automatically.

Kindly, guide me to achieve it...

Thanks,