But since this uses the total time of flight for the ball, it gives the total distance the ball traveled—to the wall and back. If you take that distance and divide by 2, you get the distance from my hand to the wall, which in this case would be 10 meters.
I like this BallDAR method because you can easily imagine throwing a ball and measuring the time. But lidar is essentially the same idea: Instead of using a ball that travels back and forth, lidar uses light. (That’s the “li” part of lidar.)
Theoretically, you could create a DIY version of lidar with a flashlight or even a laser pointer.
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