At 3 or 4 mph walking speed I don't see how it would do any good. Besides, if you're mowing at 3 inches you're probably going to clear a small tool like that anyway. Yeah, you'd need an array of sensors covering the whole width of the mower. And what happens when you're mowing a property that has buried metal debris. I have a few of those. It's going to shut off even though it's no threat to the mower.
Develop an optical system that will detect rocks, stumps and other machine killers that protrude above the cutting height of the mower and then you'll have something.
Develop an optical system that will detect rocks, stumps and other machine killers that protrude above the cutting height of the mower and then you'll have something.