DIY Batgoggles teach cheap echo-location

These DIY batgoggles may have a well-intentioned purpose – to teach the principles of echo-location to kids visiting a science center – but they also could make midnight paintballing a whole lot more interesting (and/or painful).  Bleeping angrily whenever an object or person is in front of you, they're part of Suneth S. Attygalle's "Dynamic User-centered Research and Design" project.  Echo-location relies on bouncing high-pitched sounds off of objects in your path, measuring the time it takes for the sounds to return (or the frequency they return at) to calculate how close the object is.Check out the video of the batgoggles in action after the cut

There's an Instructableif you're interested in making a set of your own.  Cost is estimated at around $60, using an Arduino-clone microcontroller.  Suneth next plans to add a sensitivity dial, and possibly wireless networking to feedback to a computer.  Perhaps a more complicated version could include an array of sensors to warn you if you're about to be shot in the back?

Okay, so the ears themselves aren't actually necessary – they just fix on with velcro, in fact – but without them you'd just be a strange person wearing noisy diving goggles out of the pool.  With them, you're DIY Batman!  I'm no echo-location buff, but would splitting the two ultrasonic sensors between the ears make for a more accurate position estimate?  Perhaps someone who understands such things could let me know in the comments.