Face Detection program to start a video on detection

I need a program that will run on a 12inch tablet (Android or Windows). It will use the front facing camera on the tablet to detect when a persons face is in front of the tablet. Recognition not needed. Only detection. The table will show a video in pause mode. Then upon detecting a face will play the video. When the video is done will return back to the beginning in pause mode and either wait 30 seconds before attempting to detect another face or wait until a face is no longer detected and a face is then detected again before starting video again. This is needed in next two weeks.