SHOWALL FUN PRANKS HIGH VOLTAGE LAZARUS-64 PHOTOGRAPHY SPY GADGETS VIDEO GAME
Figure 4 - Feeding an audio source into the speaker
Figure 4 - Feeding an audio source into the speaker

The speaker needs to be driven by some audio source, but the level should be so low that you can only hear it when your ear is right next to the speaker. The goal is to recreate the same conditions that you will be dealing with during your covert spying operations, so the reflective surface should just barely be vibrating. A portable audio player is perfect for this test because it has a low power amplifier and will run for hours at a time. Set your player to loop indefinitely and then adjust the volume as low as it will go until you can just barely hear the output from the speaker.



Figure 5 - Creating an easy to align speaker base
Figure 5 - Creating an easy to align speaker base

The alignment of the laser from the source to the target and back is not a trivial task, and as you increase the distance from the laser to the target, you also increase the error level. At 500 feet, the beam will become so sensitive to displacement that you will have to be careful when moving around the laser because the deflection of the floor inside your home will be enough to throw the beam out an inch or more. When I finally managed to setup a successful long range configuration, I found that the alignment was so sensitive that even a passing car would create waves in the system due to the vibrations between the house and the road. The laser Spy Device is certainly capable of working for many hundreds of feet away (even across a few city blocks), but vibration would become so critical that you would probably need to have everything mounted on an extremely heavy concrete or metal base secured to the ground. These are things you will find out as you experiment with this project.

To make your life easy when experimenting with the basic indoor setup, create some kind of easily adjustable speaker stand like mine using an old webcam base or adjustable bench vice. The ability to move the speaker to any angle and secure it will be key to testing the operation of your Laser Spy device as you build it. The targeting laser will also need some kind of adjustable base as well.

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