Talk to a headphones-wearing friend on a microphone made out of a matchbox and a pencil lead. Sure, you could use a regular microphone, but would it be as cool?

Say you’re MacGyver. You’re in an evil-doer’s secret lair, and are about to go and reveal his plan to the world. Suddenly, he realizes you’re there, and he locks you inside a soundproof booth (it’s an abandoned game show set) and leaves on a helicopter. Your partner is outside the booth, listening in on a headset, but the microphone inside the booth is destroyed. How do you get the information to your partner?


First of all, you don’t laugh, because that kind of situation happened every week on MacGyver. Secondly, because you’re a canny survivor who finds ways to use ordinary objects to make fantastical creations, you don’t panic. The bad guy, like all bad people, is a smoker. He’s left an empty matchbox behind. On a desk in the booth, in a cup that says ‘World’s Best Supervillain,’ you find a bunch of mechanical pencils and some extra packs of lead. You also find a 4.5 volt battery. Since the equipment in the booth is smashed, there are a lot of lengths of wire sitting around. You and your Swiss Army Knife are now ready to go!

First, cut off three sections of pencil graphite. Two should be equal in length, and just a bit longer than the length of the matchbox. The third should be a little bit shorter than the length of the matchbox. Use your knife to very carefully scrape on side of each section of graphite until it’s rough and uneven. Pierce the middle of each short side of the box twice, and thread the longer pieces of lead through, rough side up. The box, when looked down at from above, should have two parallel lines going through it lengthwise, with each line peaking out just a bit on either side. Now take the short piece of graphite and lay it down across the two long pieces inside the box. The rough sides should be put together, so the graphite pieces stick to each other a bit.

Good! You’re almost there! Take the wire connected to your partner’s headphones and split it in two. Wrap one piece around one of the protruding pieces of graphite and the other to one lead of the battery. Grab another piece of wire and connect one end to the second battery lead, and the other end to the second protruding piece of graphite. (You should be hooking the wires to the graphite bits protruding on the same side of the box.)


Pick up the box and hold it gently, keeping it parallel to the ground. Speak into it. Your voice will cause the air in the box to vibrate, and those vibrations will be passed to the graphite pieces. They’ll shake and shimmy, causing differences in the flow of the current in the wires. That flow will cause the structure in your partner’s headphones to vibrate, letting them hear whatever you have to say.

(Needless to say, this can also be done with some spare headphones in an ordinary room, but it seems a shame to waste such a neat trick when there aren’t any supervillains around. But whatever you want to do is fine.)

Top Image: Takk

[Source: The Book of Totally Irresponsible Science]