I have this idea, that I don't have neither the know how nor the time or energy to develop. But wouldn't it be great to have a tiny weeding robot, solar powered, with a tiny camera that recognizes non-weed plants and attacks weed plants by injecting either a saline/vinegar solution or electrocute the stem of the weed close to ground, walking around in the vegetable field like an insect. Something like that would revolutionize farming like the tractor did when it came in the 20th century. Only very minute amount of salt or vinegar would be used and it wouldn't be sufficient to pollute the soil...