As an extension of a drone based Ground Penetrating Radar (GPR) project the idea arose if it were possible to have a drone based metal detector.
I thought the idea silly at first but the initial numbers did not rule it out and extensive handheld testing with military grade detectors on real ordnance showed the idea may have some legs after all. If not for minimum metal AP mines, at least for the bigger stuff.
We settled on some standard detection electronics & coil which were customised and integrated with a H500 quadcopter testbed. The first test flight showed we were definitely able to pick up the detections from relatively small (tennis ball size) metal objects.
Though this proves the core concept it is of course a long way away from being something that can be operationalised (if that makes sense at all), many challenges remain. In any case given the time and budget constraints it has definitely exceeded my expectations and has been a fun project so far,