First of all, if you havent noticed from the image/title already, this instrucable is a spin-off of randofo's awesome instructable Turn Nearly Anything Into a Speaker. Also, If anyone can combine both instructables (one piezo microphone and one piezo speaker to make one big piezo system) that would be awesome!
With that being said, Today ill teach you how to turn nearly anything into an instrument by using a piezo disc as a pickup microphone. A pickup microphone works by sensing vibrations in solid objects it comes in contact with through the piezo disc. By plugging the microphone into an amplifier, you can essentially turn nearly anything into an electric instrument. I started this project to try and turn my ukulele into an electric ukulele, but I then realized I could turn nearly any solid object into and electric instrument.
My favorite part about this project is how simple it is. To build this, you will only need a piezo electric disk, an audio jack, some spare wire and some objects to make sounds with! All together I spent under $5 and made the microphone within minutes. While it is simple and cheap, don't let this microphone fool you, its actually sensitive enough to pickup your own heartbeat, as you can see in the video!
Here are the parts I used to make this project:
1. Piezo Disc
2. Audio Plug
3. Spare Wire
And thats all you need!
Optional parts I used:
Ukulele that started it all (12% OFF Coupon: 12music)
Dont forget to save on some of gearbests 3rd anniversary sale!
Step 1: Solder
To make the microphone its quite simple:
First, get your piezoelectric disc and find your positive and negative. If there are no wires on your piezo, to know which is positive and which is negative is, remember that a piezo disc is made of a thin piezoelectric ceramic with a thin brass or alloy metal disc. That means that the center of the disc would be positive while the outer ring would be negative. Next, grab your audio jack and unscrew the base. You should see two terminals to the jack a shorter tab of to the side, and a much longer one on the other. Contrary to what you would believe, the shorter terminal is the positive and the longer tab is the negative. Now just get some spare wire and connect positive to positive and negative to negative. You can make the wires as long as you want, however I used about 5 feet, to have enough room to move comfortably, but not long enough to have too much wire. That's it, all you need to do is connect the two and you're done! You can finish the microphone by adding a small piece of double sided tape to stick the piezo to the "instrument".
Step 2: Play
Now go and test your microphone! Plug the audio jack into an amplifier, turn it all the way up and start testing it on random objects. Ive found that I use the microphone the most on intruments that I want to play louder, such as a ukulele or an acustic guitar. While testing how sentive the microphone was, Ive found it can pick up your own heartbeat, take lung sounds and hear air passing thorugh vocal cords!
Here's how to hear some cool sounds
Heartbeat: Sit upright, and place the microphone directly on your chest, you should hear a familiar thump thump sound, which is the valves in your heart opening and closing as they pump blood.
To hear your lungs: Sit upright and place the microphone on your mid axillary line. Then take a deep breath in and out through your mouth. You should hear a faint clear whoooosshhh sound which is air passing into and out of your lungs.
Vocal cords: Place the microphone near your adams apple, over your throat and start taking. You should hear air passing through your vocal cords and turning into sounds!
Some other cool objects I have tested:
Foil: interesting tin sounding drum
Ruler: can play different tones based on how far away the microphone is placed
Guitar strings: by pressing the microphone to a string of the guitar, you can actually get the amplifier to play the same frequency, and the guitar will "play" itself!
Cups: makes cool drum sounds