Focusing Sound With a Parabolic Microphone
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 microphone (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 probably some kind of law against this — and if there isn’t, there should be.)
Get a bigger dish and set it up outside, hooked into speakers you set up in a permanent wildlife listening station either outdoors or in your house. (We say permanent because a dish much bigger than 24 inches needs a wheelbarrow to cart it around.) If you replace the microphone with a speaker, you could turn this thing on its head and make it a loudspeaker instead of a long-distance microphone. Look up any noise ordinances on the books before trying this one!