When I was little, I used to go to spend my summers in my grandfather’s small farm. There, I used to watch and help an agricultural worker planting crops and taking care of the field. I was super curious and whenever he was in the field, I used to get close to watch him. After I grew up I started helping and I still continue helping today whenever I visit the farm.
Sometimes he would spray liquid pesticide on crops, in fact he wouldn’t let me watch him since the pesticide he used usually contained copper-oxide which is dangerous. He used to use a face mask and proper equipment, but I had an alternative idea. So I made this robot which can spray the liquid pesticide stored in its tank to the crops at its side.
Although the robot looks a bit simple, its electronic parts were like a chaos inside its frame. I then reorganized all the inner parts and simplified the configurations. I designed and 3D printed all the blue parts using my own custom 3D printer. There is a 12V pump inside which is powered by a 3S1P LiPo battery pack. I used 2 ultrasonic sensors: The one at its side detects any crop, the one at the front detects obstacles. I bought and modified a paint spray nozzle, and attached it to the end of the pump pipe. I programmed this robot in such a way that it revolves each of its wheels exactly for the specified amount to make sure it can drive straight.
I 3D printed the liquid tank in 3 days, in fact it was not waterproof. So I poured some liquid adhesive inside the tank, and shook it for a minute. When the adhesive dried, all the holes inside the tank were filled with adhesive, and it was completely waterproof.