This is only one of a few contraptions that I was asked to share with all of you wonderful people. 

This Mob spawner is complete, save for the switch and kill platform. All redstone wire has been run to water pistons and only needs to be connected to your activation switch. I left it this way because It can be used in the air or underground, as a personal preference to the user and it was designed with that in mind.

This is not a new design and those who have played survival for any amount of time, have fiddled with this or similar designs. Remember to light up every area around this Spawner up to and including everything within a 144 block area centered on the spawner. 

feel free to ask any questions or add comments as desired.

enjoy.