
I recently received this handheld distance measurement device. Like a laser pointer, it shoots out a narrow beam of red light, making a small red dot on a surface that might be 100 feet away. It then uses a built-in telescope to view the red dot of light, and works out the distance to that surface. The device arrived today, and I compared its measurement with that of a long fiberglass measuring tape. The two approaches yielded answers that differed by only a tenth of a percent. How does it work exactly?
Star Trek fans might be able to guess where I am going with this. There were episodes of Star Trek where an enemy had somehow found a way to bypass the Enterprise’s shields, at which point the captain on the bridge of the Enterprise would shout out “modulate the shield harmonics!” In the world of Star Trek, this modulation apparently restored the protection of the shields. And indeed this kind of laser distance measurement uses a modulation of a signal to accomplish its remarkable result. Continue reading “Modulate the shield harmonics!”