untitled

Here are the types of activities that you’ll be doing to create your own para-

bolic microphone. You will

1. Put together
   
   
   • An electronic circuit containing an electret microphone cartridge
     that can pick up faint sounds
   
   
   • An IC that amplifies the sounds enough to power your headphones
   
   
   
   


2. Install the microphone in a parabolic dish that gathers sound like a
   giant ear.

We use a parabolic dish because the shape gathers sound and focuses it

on a point — in this case, on the spot where we put the microphone car-

tridge. When you point the parabolic dish at a bird a hundred feet away,

for example, the dish gathers sound only from the exact direction you

point toward and focuses the sound on the microphone cartridge.

3. Add a handle made of pieces of plastic pipe so you can hold the dish up
   easily and aim it at the feathered or non-feathered friend of your choosing.

Scoping Out the Schematic .........................................................................

By now, your mind is likely a-flutter with ideas for sounds floating around

your neighborhood that you’re dying to pick up, so it’s time to get going on

the schematic for the board, which you can see in Figure 6-2.

3

2

6

5

4

IC 1

C 3

C 5

R2 +

+

+

C 4

R3

7

SPEAKER

+

8

1

C 2

R1

+

S 1

6V

MIC

C 1

Figure 6-2:

The

schematic

of the

parabolic

microphone

circuit.

Chapter 6: Focusing Sound with a Parabolic Microphone ........................................