Tertill: The solar powered weeding robot for home gardens (kickstarter.com)

I feel like it's very likely to get stuck unless the garden is already meticulously maintained. I could be pleasantly surprised I suppose.

Sounds like this would work well in a suburb (already low maintenance) type garden with mulch and shrubs/trees etc. but since it only relies on plant height to determine what it kills would probably be terrible in a perennials garden where the desirable plants are sprouting up at different times for half of the year along with the weeds.

Sic' this thing on lawn dandelions and you'll move a million.

(Not that I have anything against dandelions, myself, except for the way they kill enough surrounding grass to promote erosion on my canted lawn.)