John Corney from Wiltshire, U.K. has taken the better chunk of the last seven years to create a robot that comes with a built-in metal detector, thanks to inspiration from robotic land mine sweepers. While the robot cost around $3,800 to contruct, John claims that he has already used to it salvage hundreds of antique coins to recoup his ‘investment’. I don’t know about you, but you sure got to be an avid coin collector if you were to splurge that much money on a remote controlled metal detector. Alternatively, you can always fork out a token sum for one of those readily available commercial metal detectors.