Adafruit Bone Conduction Speaker




About: I love creating things that make things easier for people. I enjoy breaking things apart to see what is inside of them.

After I had purchased my new iPod, I soon realized that it was incapable of creating its own sound. Thus, I decided to create a speaker that was small and light, but still had good audio quality. In the process of researching what type of speaker I should use, I came across a concept called bone conduction. A bone conduction transducer is a small speaker that does not have a moving cone. Instead, a small metal rod is wrapped around the voice coil. When current is pulsed through the coil, the magnetic field causes a piece of metal to expand and contract. This produces a sound that can be passed into objects. If pressed against a flat surface or cavity it turns it into a speaker. After reading this I decided that I must make one for myself.

This cheap bone conduction transducer allows you to turn any surface into a speaker. With its sleek 3D printed case, it not only looks nice, but it sounds good too. Once you have created these speakers, you no longer have to bring heavy impractical speakers to share your favorite songs with your friends.

Made by: BruceE3 and r2pen2


Step 1: Tools and Materials+3D Print

All of the materials can be gathered from Adafruit


Amplifier board - we suggest the MAX98306 or TS2012

-Bone Conductor Transducer

-150mAh Lithium Ion Polymer Battery

-Stereo Headphone Jack

-Slide Switch

-JST Battery Ext. Cable



-Wire stripper

-Soldering iron

-3D printer


-File/ Sandpaper

Most of these tools you should already have. If you do not have a 3D printer then you can take the STL file and send it to a company that 3D prints things for people. I recommend either white or clear for the filament, and printed under the highest quality settings. Supports are not necessary.




Step 2: Solder

Solder the bone conduction transducer to one of the two amplifier channels. Next, solder a small wire to R- and L- connections on the TPA2016 amplifier board. After, connect the AUX input jack to the R-, R+ and L+ connections on the board. Lastly, connect the power source to the VDD and GND connections on the top of the board. Once this is all soldered together, test the transducer on your computer.

Step 3: Assemble!

After you completed the circuit, all you need to do is shove the circuit into the 3D printed box. The transducer should fit snugly in the bottom of the 3D print, and the AUX cable will snap into the cap on top. The rest will should fit snugly inside the body of the 3D print.



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    18 Discussions


    17 days ago

    Great tutorial and downloadable project. I'm wondering if this could be linked up to a Bluetooth earpiece instead of the usual speaker? Also, do you think it's possible to solder the transducer to the amp board and to connect all of that to a standard headphone jack in order to plug it into an iPod nano or shuffle??
    Any help would be greatly appreciated!


    1 year ago

    Would this bone conduction transducer work in place of a normal speaker on a Bluetooth speaker set up, I wear hearing aids and I can't use my mobile phone properly so if I replace the speaker with the bone conduction transducer I'm hoping to have normal conversations on my mobile.


    3 years ago

    Hello BruceE3, first of all I want to thank you for this tutorial. Then I would like to ask you some things:

    1. Why I have to use switch slider?
    2. About battery, how much it can do before getting discharged? And it's rechargeable? If yes, how?
    I'm deaf but I can hear through bone conduction and I will use this for
    listening telephone calls because I can't do it right now. If I connect
    it to my smartphone, do I need to use the amplifier board? Why?

    you for your time, I will appreciate and sorry of course for my
    questions as newbie but I want to start calling with this by myself and
    not through other people :)

    3 replies

    Reply 3 years ago

    Thanks for your comment, so hopefully I can provide some answers to your questions. First of all, you do not need to use a slider switch, as any switch will do. The switch is only there so you may turn the device on and off. The battery is lithium, and as such, is unpredictable in it's life, though you can ensure that it will last about a few days with regular days. You are able to recharge the battery, by removing it from the circuit and charging it separately. When connecting the bone conduction speaker to your phone, you will be using an AUX input, meaning your standard headphone cord. The amplifier board ensures that the other parts of the circuit function on par with the speaker. I hope I was able to provide some answers to your questions.


    Reply 3 years ago

    Hey BruceE3, thanks for your answer. So ok, I understand the all, do you know what can I use (from Adafruit) to charge the battery?
    And about the connection to my phone, do I need to use the amplifier or it will work also without it?
    I'm asking this because if you don't need it, I can remove battery and amplifier no?


    Reply 3 years ago

    You may be able to get away with not using anything and just hooking this up to a headphone jack. Technically it's supposed to work, but it just may be so incredibly faint that you can't hear it. You only need the battery for the amp so without the amp you have no use for the battery.

    As for a charger for a battery from Adafruit, that's a pretty lazy question if you don't mind me saying. I bet if you are on the product page for the battery it will suggest one. If not, a search on their site for lipo or battery charger will surely find it.

    Good luck bro.


    4 years ago

    A priezo could also work as a bone conduction transducer. You got the general function right, it vibrates against a surface to produce resonant sound, works best on bone because bone resonates at the largest frequency span, comparable to the ear drum. The transmission by bone is simply because it bypasses the eardrum and conducts directly to the cochlea. Using it in the fashion you have here works, but as you have stated, highly depends on the resonant frequency of the material you are using it against.

    2 replies

    Reply 4 years ago on Introduction

    showing my age, but I remember a bone phone headset like device, it went around you neck and the transducers sat on the collar bone.

    Recently 5 years ago, I lost hearing in my right ear from a cyst. I had a BAHA installed. they mounted a snap to my skull behind my ear and device snaps to it, works as you described. I can even tell the direction sound comes from.


    Reply 3 years ago on Introduction

    It's great that you've been able to regain (some) of you hearing. And I think that these things have indeed been around for a little while.


    4 years ago on Introduction

    Does the trasducer need to be next to a bone for you to be able to hear it? Or does it work similarly to a regular speaker?

    1 reply

    Reply 4 years ago on Introduction

    It works similarly to a regular speaker, and you can hear it without it touching anything, though the sound quality will be low. To hear the bone conduction transducer at full quality, place it on a bone cavity near your ear. To turn other surfaces into a speaker press it against acrylic, wood, plastic, or glass for the best results.


    4 years ago

    I worked on it with him. Yes it needs to be a bone conduction transducer.