You can turn nearly any object into a speaker by using a piezo disc and a handful of additional components. While this may seem like magic, there is actually a rather simple technical explanation. By driving a piezo disc using an amplifier, the disc vibrates and then resonates the sound wave through whatever object the disc is attached to. When the object vibrates, it disturbs the air and makes sound. This is not only a fun trick, but also allows for a lot of interesting experimentation and creative projects.

Step 1: Materials

To Turn Nearly Anything into a Speaker you will need:
(x1) Audio output transformer
(x1) Small Amplifier*
(x1) Small project enclosure
(x2) 1/8" mono jacks
(x1) Piezo disc element
(x1) One-sided 1/8" male mono cable***
(x2) 1/8" male-to-male mono (or stereo) cable
(x1) Double-sided tape

* It has been brought to my attention that the Radioshack test amp I used is no longer available since they went out of business. You might still be able to find it on Ebay. This one that is linked should work as replacement.

To connect the amp's output to the piezo I recommend just buying a female jack adapter, and connecting wires between the adapter and one of the red and black pairs of speaker output ports in the back (black-to-ground, and red-to-left). Then plug the piezo cable into the female adapter.

*** This type of cable has a plug on one end and a signal and ground wire on the other end. If you can't find one, then just buy any old male-to-male mono cable and cut off one end, and strip away the insulation to expose the wire.

Step 2: Holes

Make a mark centered upon each of the 1" x 2" sides of the project enclosure.

Drill both of these marks with a 1/4" drill bit.

Step 3: Wire the Jacks

Attach 3" black wires to the center barrel pin of each, and 3" red wires to the pin connected to the outer signal tab.

Step 4: Wire the Transformer

Since the transformer is basically two coils in proportion to one another, the only thing to be mindful of is aligning the wires when they are soldered.

Solder one set to the outer pins on one side of the transformer, and the other set mirrored on the opposite side. The colors of the wire should be aligned.

Trim the center pins on the transformer. We are not using these.

In a schematic, a transformer is represented by a double-line core surrounded by two coils.

Step 5: Insert the Jacks

Insert the jacks into the mounting holes in the enclosure.

Make note of which jack is connected to the side of the transformer labeled "P". This stands for primary.

Typically the primary is the input side, but we are actually driving the transformer backwards, so the primary side is our output to the piezo.

The reason the input is the output is because of impedance, a concept we are not really covering in this class, but one particularly important when dealing with transformers and AC electronics. Long story short, impedance is kind of like resistance in AC electronics (but not exactly the same). Typically, audio sources have a high impedance of a few thousand ohms, and speakers have a low impedance around 8 ohms.

The audio output transformer is designed to take a high impedance source and make it low impedance. However, we have the opposite problem we need to solve. The piezo is typically a high impedance device, and the audio amplifier is always providing a low impedance signal to drive a speaker. In order to drive the piezo using the amplifier, we need to take the low impedance output from the amplifier and make it high impedance. To do this, we simply send the low impedance signal from the amplifier into the low impedance coil, and this will produce a high impedance signal to drive the piezo. Simple as that.

Step 6: Glue (optional)

Hot glue the transformer to the base of the enclosure. This is not entirely necessary, but will ensure it does not accidentally get damaged.

Step 7: Close It Up

Close the case with its mounting screws.

I recommend that you use tape, a sticker, nail polish or a marker to indicate the output on your enclosure to eliminate guesswork. In my case - or should I say on my case? - I cut a piece of white tape into a little arrow.

Step 8: Wire the Piezo

A piezo disc is basically a metal disc with a special piezoelectric ceramic coating. This is a special type of material that expands and contracts when electricity is applied, and can also produce electricity when expanded and contracted.

It is different than a speaker in that it does not use any coils or magnets, but has some similarities. Like a speaker, it can work as a transducer to both turn sound into a voltage and voltage into a sound.

To be able to drive the piezo disc, we first need to attach it to an 1/8" mono cable.

Solder the center signal wire from the cable to the solder blob on the center of the piezo disc.

Solder the outer shielding wire to the solder blob on the golden outer ring of the disc.

Trim away all of the excess wire leads.

Step 9: Connect Cables

Plug the piezo disc wire into the output side of the enclosure (connected to the primary), and connect a male-to-male mono (or stereo) cable into the input side of the enclosure.

Step 10: Amp

Connect the input from the transformer enclosure into the output from the amplifier. This connection enables the amplifier to drive the transformer.

Connect any audio player into the input using a mono (or stereo) cable.

Step 11: Tape

Apply two small pieces of double-sided tape to the flat side of the piezo disc.

Step 12: Stick the Piezo Onto Something

Once everything is wired up, stick the piezo onto a surface that you want to make music.

Don't forget to turn the amp on, and the volume up.

Step 13: Stick the Piezo Onto Everything

Stick the piezo onto any item you want and discover its hidden musical potential.
<p>My cheese grater will never be the same again!</p>
<p>What if you stick it to the human body?</p>
Check out bone conduction headphones.
<p>It depends on the part of the body. For a really strange experience, put it inside a plastic bag and bite down gently upon it. </p>
<p>If you stick the piezo to a large piece of wood, have you created a &quot;log o' rhythm&quot;? :-)</p>
what transformer actually does? since W in is same as W out
<p>I was thinking isolation to protect the amp but does it need that? </p><p>That xfrmr is designed for impedance matching but what needs to be matched? it's 1kohm to 8 ohms, but the amp is 8 ohm out. The piezo is 300 ohms, so you'd have to hook the primary [1k] side to the piezo disc to IMP match.</p>
<p>lol this was 4 years ago, he probably changed the part and explained why he used transformer</p>
Good question. I omitted the piece with the transformer, and it appears to be working fine. I don't have the knowledge to tell you which is better though.
I'm guessing impedance matching. Increases efficiency.
<p>Forrest Mims describes experiments with piezos in his books, in case any of you want to explore some more.</p>
<p>Aaaah. But what does grating parmesan sound like? Cheddar? Carrots? By that, I mean to ask, how do things sound to an amplified cheese grater or whatever. Like ordinary speakers, piezoelectric elements can serve as microphones. Connect one to the input of an amplifier to hear the sound. I'm not sure if an impedance-matching transformer is necessary in this case. (No, I haven't actually built one.) </p>
So I'm sure a few of you folks have seen/heard about what's called a &quot;ROCKIT&quot;? it's a commercial version of this project which works very well! Just wanted to say that I saw that this instructable should cost around $40 to complete... I bought a &quot;rockit&quot; at goodwill a few weeks ago and paid three bucks for it... And there were brand new batteries in it! So...
The cheese grater speaker only sounds good with polkas from Wisconsin...
<p>I find it a little raspy.</p>
<p>but then it sounds Gouda!</p>
<p>Actually it sounds grate!</p>
<p>A speaker reproduces sound. It doesn't create or color it.</p>
<p>The fact than an object can be made to vibrate when stimulated by an audio signal doesn't make it a speaker any more than a dental filling that picks up an RF signal can be called a radio. The ability to vibrate does not equal &quot;Musical Potential&quot;.</p>
How much does this cost to make, minus 'everything' (for sticking the piezo on :D)?
<p>I would say $40 - $50 if you have to buy all of the materials including the amp.</p>
Dude, awesome project bro. I've seen something similar to this called rock it 3.0. link:https://www.amazon.com/OrigAudio-ROK3-W-Portable-Vibration-Speaker/dp/B008CTM94G<br><br>Also I'm curious; what does it feel like when you put it on your hand?
<p>It feels like slight tingling or vibrating. </p>
Just a tip: Sparkfun sells transducers, I think up to 1W that are decently priced. Just if you want more POWER! (cue Jeremy Clarkson)
<p>Don't you mean &quot;Cue Scotty.&quot; ?</p>
<p>Hi! May I just ask how you obtained the piezo discs? I mean, is there any way I could make the discs myself? Or, may I know where you bought the discs? Thanks!</p>
<p>They're pretty cheap to get at basically any local electronics store and also via ebay. In the case of ebay you might have to wait a couple weeks or so for them to arrive with chinapost. Here's a link for 3 pieces for a dollar: <a href="http://www.ebay.com/itm/3PCS-27mm-Piezo-Elements-Sounder-Sensor-Trigger-Drum-Disc-wire-copper-Z3-/261920058340?pt=LH_DefaultDomain_0&hash=item3cfba6ebe4" rel="nofollow">http://www.ebay.com/itm/3PCS-27mm-Piezo-Elements-S...</a></p><p>And a link for 20 pieces for 2 dollars:</p><p><a href="http://www.ebay.com/itm/20PCS-12mm-Piezo-Elements-Sounder-Sensor-Trigger-Drum-Disc-wire-copper-/251892194809?pt=LH_DefaultDomain_0&hash=item3aa5f1ddf9" rel="nofollow">http://www.ebay.com/itm/20PCS-12mm-Piezo-Elements-...</a></p><p>I hope that'll suffice</p>
<p>I don't think Nicolas Collins would mind you using his (exact) setup to turn a piezo disc into an audio driver, but the least you could do is mention that you got every single part of this instructable except for the pictures from his (excellent) book &quot;Handmade Electronic Music: The Art of Hardware Hacking.&quot; Parts numbers, even the exact same battery powered amp. C'mon dude. Have some integrity. At least so you can spread around the knowledge of said book! To anyone else reading, definitely check it out, it's got way more audio projects than just this, and even some interesting circuit-bending and video sections.</p>
<p>Sold two books! love learning about hardware hacking. I'm actually writing an essay for my English class about green and free energy and how anyone can build their own contraptions with unused stuff or recycled stuff to produce enough energy to run their house hold from including use of wind/solar/magnetic energy sources. what another great discovery for myself, because i might have an idea for this. well two ideas, one for energy research, and to see how it would work with my headphones i made from 3M hearing protection, they sound good now, but it still needs an amp, more base and maybe surround sound capabilities (anyone have any suggestions on any of this?)</p>
<p>This comment sold a book. </p>
<p>Thanks for pointing that out. I'd be sure to check it out</p>
<p>okay. You used a Amp and a Transformer to drive the piezo. Is the transformer really needed or it will work fine without it?</p>
Kazmataz: your comment is so cheesey! But you are quite sharp. :) is it wrong that I expected to see a photo of this thing stuck to an 8 track? Retro-fun?
What kind of frequency response do you get out of it? I'm assuming we're not talking hi fidelity here, but how good does the sound get if you attach it to an optimal surface?
A video, a video, please please give us a video :-)
I thought about it, but it would be really boring to watch and the audio would probably not sound very good.
Oh stop, I'm sure the cheese shredder sounded grate
Bahahaha! It was OK, but I think he's sticking with the glue gun.
marry me, please
Nice answer :-) <br>Like. Like.
Oh thanks kazmataz! Randy, go and explore the power of video editing. You can do it, really!
so does the audio output transformer really work in matching the impedance ? I've been trying to get a piezo pre amp for a while now, and so far no luck. any help is appreciated . great instructable. Saif
Does it matter witch side its plugged into
freak......Nah just another great tutorial :D
The cool thing about this is you can easily modify this to &quot;Turn nearly anything into a microphone. Just watch out for feedback. Great ible.
This is now a way to have music everywhere where a body ain't allowed to have it. Just use a body that will resonate when you strike it with a metal object like a small hammer and it must &quot;ring&quot; Excellent idea
Awesome :o

About This Instructable




Bio: My name is Randy and I founded the Instructables Design Studio. I'm also the author of the books 'Simple Bots,' and '62 Projects to ... More »
More by randofo:Build a Mad Scientist Light Useless Machine Instructions LED Flashlight 
Add instructable to: