For the sweeper, I should throw the bristles on a spring loaded thing with limit switches. This will be so if it hits something at one of the tips of the bristle head, it can register the touch, and behave accordingly. I’m still thinking of how to register the cleanliness of the floor. My current best thought would be a light pulse, and look for how fragmented the bounce back is. Maybe a polarized filter could do it cleanly. Really, I should just build a thing, mount a lot of crap to it, and then look for changes in measurements.
Peter's stuff.