I also had this as a kit when I was a kid - it was one of the experiments one could perform with the home-built laser I constructed. I built the receiver, gave it to my little sister, and off she went over the dunes .. we confirmed the experiment, and she subsequently lost the receiver in the dunes. Always wished I'd been the one to go out that day ..
There was another experiment where you could shine the laser on a window, and pick up its reflection and using that, listen in on the room. It required a more complicated circuit to be built, so I never did it, but its fascinating that such technologies were, in the 70's and 80's, available to inquiring teenage minds.
Comments
When I was a kid I had a a kit for doing this.
This also the principal behind spying on someone in a room by watching the wobble of reflected light on a window.
I also had this as a kit when I was a kid - it was one of the experiments one could perform with the home-built laser I constructed. I built the receiver, gave it to my little sister, and off she went over the dunes .. we confirmed the experiment, and she subsequently lost the receiver in the dunes. Always wished I'd been the one to go out that day ..
There was another experiment where you could shine the laser on a window, and pick up its reflection and using that, listen in on the room. It required a more complicated circuit to be built, so I never did it, but its fascinating that such technologies were, in the 70's and 80's, available to inquiring teenage minds.