This compact proximity sensor is really fast detecting and compact. If you are wondering what a proximity sensor is, it is a machine that detects when a player gets to a certain area, usually created with a villager spawning on a pressure plate. This one, using the new test function in a command block can have the block radius set and still will detect the player really fast.

I'll soon add a link to one created with usage examples.

Please note this requires snapshot (Or 1.5 + depending on when you are viewing this) 13w03a.

Also, it is completely silent.

Thanks for viewing, hope this helped!

~Pi