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How to make a microphone for 5 bucks (Free Lunch Included)

Picture of How to make a microphone for 5 bucks (Free Lunch Included)
 Why pay tons of money for a professional microphone when you can make a microphone yourself? Granted this microphone will not give you a crystal clear sound, but you will get that cool retro low-fi sound.
 
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Step 1: Materials Required

Picture of Materials Required
 1. Can of your favorite soup. 
2. 1/4" phono jack
3. Piezo element
4. Styrofoam
5. Wire
6. Solder
7. Duct Tape

Tools Required:
1. Drill
2. 3/8" drill bit
3. 1/8" drill bit
4. Soldering Iron
5. Can Opener

Step 2: Eat Your Soup

 In order to use the can for your microphone, the soup must be eaten. Please follow instructions on can for soup preparation.

Make sure to keep the top when you open the can. The top will be used in the next step.

Step 3: Attach the 1/4" jack to the top

Picture of Attach the 1/4
 ** The top of the can is very very sharp to be careful in this next step **

Take the top of the can and hold it in a vise so the top is stable. Use the drill and drill a 3/8" hole in the center of the can top and insert the 1/4" jack and make sure the nut is tight.

Step 4: Drill hole in side of can for the wire

Picture of Drill hole in side of can for the wire
 Use the 1/8" drill bit and drill a hole on the side of the can. The hole should be about a quarter of an inch from the bottom of the can.

Step 5: Insert the Piezo

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 Next the piezo element must be inserted in the can. Some elements contain wires that are too short, so it might be necessary to extend the wires.

To extend the wires, first strip the new wires. Then apply some solder to the tips of the new wires and the wires on the piezo. Then heat up both tips and hold together and let cool. Make sure the joint is strong. 

In order to make sure the two wires don't short out, use electrical tape. First wrap electrical tape around one wire, and then wrap around the other in order to keep both wires from touching.


Step 6: Solder the Piezo to the Jack

Picture of Solder the Piezo to the Jack
 Next, insert the piezo element in the can and fish the wires out from the small hole drilled on the side of the can.

*** Be careful not to cut yourself on the edges of the can ***

Next, solder the wires to the jacks. It is suggested to first put solder on the jack terminals and on the ends of the wire and then reheat the solder to attach the wires to the jack.

Step 7: Tape piezo inside the can

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 Make sure the piezo (white) part of the element is facing up and centered on the flat part of the can. When this is done, keep the element in place while sticking a piece of duct tape above it. Use blunt object to make sure the tape is holding the element down securely and there is no gap between the can and the element.

Step 8: Cut styrofoam to use as a filler

Picture of Cut styrofoam to use as a filler
 In order to make sure that the 1/4" jack doesn't touch the bottom of the can, styrofoam is used to occupy the space. 

Once the styrofoam is cut, hold everything in place and tape up the bottom of the mic.

Step 9: A functioning microphone!

The microphone is done! Enjoy it, and I hope you are full from that hearty lunch!
For a quick audio demo, watch the video below. 
pigeonpants4 years ago
I'm wondering how you "hold" this mic while recording? Does having it in some kind of mic holder (obviously that you'd have to special make for a soup can ;D) "dampen" the vibrations of the can too much so that it effects the sound? Or do you generally just speak into it just like soup can telephones? I guess I'm thinking of how if you have your hand on a bell, it kills the sound of the bell. I think the piezo is sensitive enough for that not to be a problem, but I'm just wondering.
Instead of making it with the Styrofoam on the outside of the can, why not tape the piezo on the foam inside the can and put the jack in the bottom of the can. Benefits: 1) reduced size, 2) reduced can vibrations messing with the signal, 3) can functions as a wave guide better.
Possible alterations: Add a cone to it