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Trying It Out..................................................................................................

At this point, the microphone is ready to go, but here are a few tips to help you

be kind to your ears — you can get some really loud noises out of this thing.

Before putting on the headphones,flip the switch on and adjust the

volume control.

You’ll be able to hear enough to make sure you don’t have the volume so

high that it hurts your ears.

Avoid knocking the parabolic dish against anything like a tree trunk

or your cat while you have the headphones on. The resultant ringing in

your ears is not a desirable thing.

Avoid having any “friends” shout into the parabolic dish, or anywhere

near it, while you have the headphone on.

Time to get this thing in gear. Here goes:

With the headphones on your head, flip the On switch, point the thing at

something you want to listen to (such as a neighborhood bird or your best

friend), and listen.

If you don’t get the results we got, here are some options to check out:

Check that all the batteries are fresh, tightly inserted in the battery

pack, and face the right direction.

Check that no wires or components have come loose.

Compare your breadboard with the photos to make sure all the wires

and components are connected correctly.

Taking It Further...........................................................................................

After you wander around your neighborhood with your parabolic micro-

phone (and explain to curious passersby what that thing is), you might want

to try some variations. Here are our suggestions:

Instead of headphones, hook up a tape recorder to the circuit and record

sounds. (Once again, do not record your neighbors because there is prob-

ably some kind of law against this — and if there isn’t, there should be.)

Chapter 6: Focusing Sound with a Parabolic Microphone 137