The lid from a cooking wok will serve as a parabolic dish, a device that will focus all sound bouncing off the inside surface of the dish to a single point— our microphone in this case.
Because of this effect, you can "focus in" on very distant sound sources much like a satellite dish can focus in on the faun signals reflected from orbiting satellites.
Our Evil Genius minds are already concocting more ideas! The schematic for the bionic spy ears (shown in Figure 2-7) is remarkably simple, using only a single FC, variable resistor, microphone, and capacitor for each audio channel.
You will find many other projects, photo galleries and a support forum at ATOMICZOMBIE. We always look forward to seeing what other Evil Geniuses create and sharing ideas. The LM386 is a very common 1-watt audio amplifier IC used in many small audio appliances such as multimedia speakers, small radios, sound cards, and telephone equipment, and it is set up in our circuit to amplify the audio from the electret microphone's internal amplifier with a gain of 200.
This book will fill a gap that has been open for far too long. Using easy-to-find parts that will not crash your budget, 101 Spy Gadgets for the Evil Genius will show readers step by step how to build their very own spy gadget arsenal.
Even the young Evil Genius will be able to build most of the devices presented in this book, and the hardened techno nerd will appreciate the novel ideas and cutting edge quality of the higher end projects.
O W •H c O ■H I cn 4l o a o ft u o •H 2 •A Q •H H O -Q ft M a J CM I -P u a) •n o M Project M— Parabolic Dish Microphone For this project, we are going to cook up a device that can focus in on distant sounds much the same way a satellite dish can focus in on weak distant radio waves, and for this we will need a large cooking wok, or at least the lid from one.The 50-k Q variable resistor will allow you to tweak the voltage level fed to the electret microphone, which will also control the volume of each channel.This method of volume control ensures that each channel can be tuned for equal amplification, as these electret microphones can vary somewhat even though they may see the same input voltage.So many great gadgets to keep the older brother at bay! I think agent Mulder from the show 'The X-Files' said it best; "trust no one." and "the truth is out there." If the truth is really out there, then the devices presented in this book will help you dig it out, and soon you will know who you can trust — with a little help from our stealthy spy gadgets!In 101 Spy Gadgets for the Evil Genius no leaf is left unturned — if it has wires, this book will show you how to hack it, turning seemingly ordinary household appliances into devices that even 007 himself would appreciate. Security is one of the largest industries in the world today — with everything from theft prevention to high stakes corporate espionage in the hit list, and knowing how to get at the truth is a valuable asset indeed.