This is "Mr Ghost" a $20 EMF detector for iPhone

Now this is a cool kickstarter project, turn your iPhone into a ghost detector!
From the kickstarter page:

"Fancy yourself a ghost hunter? Mr.Ghost plugs directly into your mic port to detect electromagnetic radiation sources."

and

"Have you ever looked at your iPhone and thought, "Wow, this thing is impressive! But I wish it had a detachable EMF detector!" Well, we did! So we made one.

Mr.Ghost is an EMF detector that plugs right into the headphone jack of your iPhone. You use our free app to detect invisible EM radiation from household appliances, your car, whatever's in your closet or under your bed, or anything you want to point it at."

busting makes me feel good

more here