#10: Improvised Spy Gear

[RPGnet Columns]

http://www.rpg.net/columns//hack//hack10.phtml

Summary:

Espionage equipment you can make yourself.

Go to the column for more information.

[Motorskills]

The first time I heard about using lasers for surveillance was, I think, in the late 1980s, during a role-playing session. Everybody around the table was like "That's so cool!".

The first time I saw it in "action" was the movie Clear and Present Danger, which I think was mid-90s. But it was obviously an accepted technique even then, since there was no real explanation of what was going on.

When was the technique discovered? Or was it widely-predicted, way before the technology existed to make it a reality?

[Clay]

It's one of the oldest uses for lasers. It works in exactly the way that fiber optic communication works.

A fiber optic cable has special sheathing that keeps light from leaving the cable even as it goes around corners, so there is considerably less attenuation, and the sensors are much more sophisticated. Cadmium Sulphide photo cells are cheap and ubiquitous and old tech. They're the sensor used for outdoor light sensors, like what I have my Christmas lights rigged up to. Right now you can pick up the whole deal for $10 at Home Depot, although the cell itself is probably cheaper at Radio Shack, if you can still find one that sells electronic components. You could go to a dedicated electronic supply place as well, but those are a lot less anonymous, which could be important in this context.

The other thing is that you'll have to work out the angle of reflection pretty carefully. If you can't get a room directly across the street from the target window, you'll need to secure two spaces. One will launch the beam, the other will pick it up. You can play around with bouncing a laser pointer off a mirror to get an idea of how it works. With a little bit of high school trig you could work out exactly where to put the listening station.

You can also buy Helium Neon lasers for $100 or less that are pretty powerful and might be more appropriate, especially if your building is on the other side of a river or something. Just remember that distance also multiplies the divergence between the source beam and the reflected beam, and weather can do bad things to signal strength. A fog bank, for instance, would completely kill your listening.