Chapter 6
Focusing Sound with a
Parabolic Microphone
In This Chapter
Looking over the circuit
Organizing the parts list
Putting the microphone circuit on a breadboard
Assembling the dish
Picking up sounds all over the place
W
hen’s the last time you stepped outside your door and really listened
to all that noise out there? There are birds, traffic noises, maybe a cat
slinking through the tall grass. Of course, some of these sounds you can pick
up with your own two ears, but others aren’t so clear. A microphone that
could help you pick up those softer sounds — whether made by your buddy
whispering to you 100 feet away or birds in the trees — might come in handy.In this project, we show you how to put together a microphone and an IC to
amplify noises that it picks up. Then you can put the whole circuit together
with a parabolic(curved) metal dish that picks up sounds, just like how cup-
ping your hand behind your ear helps you pick up sounds.What a Dish! The Project Overview ...........................................................
A parabolic microphone kind of looks like a TV satellite dish. Instead of pick-
ing up electromagnetic broadcast waves, though, this kind of microphone
picks up sound waves. Sound wavesare simply vibrating molecules that
deliver all kinds of sounds, like birds chirping and your neighbors’ latest
argument. (Disclaimer:Of course, we’re NOT recommending that you use
this project to eavesdrop on anybody!) You use the microphone, the curved
dish, and headphones to gather and deliver the amplified sound to your ears.