Turn Nearly Anything Into a Speaker

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Introduction: Turn Nearly Anything Into a Speaker

About: My name is Randy and I am a Community Manager in these here parts. In a previous life I had founded and run the Instructables Design Studio (RIP) @ Autodesk's Pier 9 Technology Center. I'm also the author of…

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.

Please note that some of the links on this page contain Amazon affiliate links. This does not change the price of any of the items for sale. However, I earn a small commission if you click on any of those links and buy anything. I reinvest this money into materials and tools for future projects. If you would like an alternate suggestion for a supplier of any of the parts, please let me know.

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.

Did you find this useful, fun, or entertaining?
Follow @madeineuphoria to see my latest projects.

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    68 Discussions

    0
    portablewho
    portablewho

    Question 17 days ago on Introduction

    I was looking exactly to make my own version of the Rock-it speaker and glad i found this, but just a question, if the piezo is turning any object into the speaker, is there also sound coming out of the little amp speaker you show also?

    0
    randofo
    randofo

    Answer 16 days ago

    No. The speaker in the test amp is turned off when there is a cable plugged into the 'amplifier out' jack.

    0
    MrErdreich
    MrErdreich

    5 months ago

    Awesome electronics project idea for my students, thank you!

    0
    Count Volta
    Count Volta

    2 years ago

    I like the piezo cheesegrater speaker!

    ha ha ha ha! Very inspiring.

    0
    LJM6
    LJM6

    3 years ago

    can this be used to play ultrasound?

    0
    jdscomms
    jdscomms

    3 years ago

    Thanks Randy for posting this. I'm having trouble finding the Xicon 42TM013-RC transformer in stock. Can you recommend any alternative models?
    - Thanks, John

    0
    Spaceman Spiff
    Spaceman Spiff

    3 years ago

    My cheese grater will never be the same again!

    0
    ShekharSahu
    ShekharSahu

    3 years ago

    What if you stick it to the human body?

    0
    cdizzle716
    cdizzle716

    Reply 3 years ago

    Check out bone conduction headphones.

    0
    randofo
    randofo

    Reply 3 years ago

    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.

    0
    gen81465
    gen81465

    3 years ago

    If you stick the piezo to a large piece of wood, have you created a "log o' rhythm"? :-)

    0
    Cekpi7
    Cekpi7

    7 years ago on Introduction

    what transformer actually does? since W in is same as W out

    0
    eGadgetGuy
    eGadgetGuy

    Reply 3 years ago

    I was thinking isolation to protect the amp but does it need that?

    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.

    0
    Cekpi7
    Cekpi7

    Reply 3 years ago

    lol this was 4 years ago, he probably changed the part and explained why he used transformer

    0
    mythicalbyrd
    mythicalbyrd

    Reply 7 years ago on Introduction

    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.

    0
    bclamore
    bclamore

    Reply 7 years ago on Introduction

    I'm guessing impedance matching. Increases efficiency.