Build the long range Laser Spy system
The Laser Spy System is considered by many to be the Holy Grail of high tech spy devices because it can give the user the ability to listen in on conversations that take place in a distant building without having to install a bug or transmitter at the location. The Laser Spy System was said to be invented in the Soviet Union by Leon Theremin in the late 1940s. Using a non-laser based infrared light source, Theremin's system could detect sound from a nearby window by picking up the faint vibrations on the glass surface. The KGB later used this device to spy on the British, French and US embassies in Moscow. It is also interesting to note that Leon Theremin invented the world's first electronic instrument, a wand operated synthesizer named "The Theremin" after him.
The Laser Spy System goes by several names such as the Laser Microphone, Laser Listener, Laser Bug, Window Bounce Listener and a few similar names. The Laser Spy certainly works well under ideal conditions, but it has many strengths and weaknesses that will be discussed in this plan. Building your own Laser Spy is by far the best way to experiment with this technology as you can adjust the design to suit your needs, rather than forking over hundreds or thousands of dollars for an assembled kit that will likely be far inferior to one that you can build yourself. Many of the kits I have seen for sale over the Internet not only use dated technology, but they incorrectly state that the system uses a modulated laser beam to convert window vibrations into sound, which is simply not the case. Let's put the mysteries to rest once and for all and build a working Laser Spy System from the ground up and explore the functionality of each subsystem that makes a working unit.
We will be starting with an ultra basic proof of concept test system that will show you how the Laser Spy converts vibration into sound and how careful alignment of both the laser and receiver are required for optimal performance. Ironically, the most basic configuration may prove to be the most useful, and the $20 you spend in parts could create a system that works as well (or better) than some of the ones that are for sale on the internet for thousands of dollars. As you will find out, the key to spying with a laser beam is in the alignment and reception of the beam, not some magical black box full of fancy filters and optical components
The first time I experimented with a laser spying device was in the 1980s when I found a DIY article in an electronics magazine. Lasers were huge, expensive beasts back then, but I was nerdy enough to have one to mess around with and followed the instructions in the article. In the end, the system was found to be 100% useless, and rumor at the time suggested it was all just a hoax. What happened was that the article failed to mention that as cool as this device was, it was extremely difficult to set up in the real world, especially when trying to bounce from a distant window. Believe me when I say that this device does indeed work, but using it to spy across the street will require a serious amount of setup, fine tuning and patience. To be perfectly honest, your chances of simply beaming toward your neighbor's window and hearing anything are about 1,000 to 1 against you. So many factors have to be in your favor, such as the type of window, the alignment of the structure, the time of day, the level of sound, and mostly, your patience level. I have done a successful window bounce from across a city street, but it was NOT an easy task, so keep that in mind. Any site selling this device in kit or plans form claiming that it is "point and shoot" should be deleted from your favorites in a hurry!
Read more...
http://www.lucidscience.com/pro-laser%20spy%20device-1.aspx
Don
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