According to YouTuber “Sciencish,” the three things he hates the most about the summer are ticks, mosquitoes, and poison ivy. While there’s bug spray for… bugs, there’s no real equivalent for poison ivy. He decided to handle this with, you guessed it, a robot dog.
To make this quadruped, he modeled a dog frame that holds an Arduino Uno for control along with eight servos. He first tried using tiny 9g servos to move the bot around, but eventually switched to full-sized models when those proved insufficient. Servo positions are calculated with trigonometry, using inverse kinematics so that he can simply plug in the X position and leg heights in the program to produce the correct angles. These servos handle movement duties, but to actually kill weeds, it also has a reservoir in the snout area to hold weed killer. When in position, the robopup lifts one of its legs to avoid the strategically placed dispensing tube, pouring liquid onto the offending plant.
In reality, the reservoir can be filled with all kinds of liquids, perhaps pouring water on good plants to encourage their growth. It can even be used for what at first appears to be fire extinguishing duties at around the 4:10 mark, though watch a little longer and the results aren’t quite what you’d expect. It’s a fun project, and something that can hopefully be built upon further in the future.