title_body: Barometer vs Rangefinder
upvoted_answer: Technically, you don't need a rangefinder or a barometer for a normal drone but if you want to make a drone with altitude hold, I would recommend a barometer over a rangefinder because a rangefinder will not work very high up or when you are flying over certain surfaces like water. A rangefinder would only be good if you stay close to the ground and don't fly over reflective surfaces.