https://www.youtube.com/watch?v=IS2uS_aWTHw

Turn almost anything into a speaker with a bone conductor transducer and Adafruit's TPA audio amplifier.

If your next project needs some sound, a bone conductor transducer will have you experimenting with all sorts of objects. If you've ever wired a speaker system before, you'll find this DIY electronics project is fun and easy!

This incredible speaker does not have a moving cone like most speakers you've seen, instead, a small metal rod is wrapped with the voice coil. When current is pulsed through the coil, the magnetic field causes a piece of metal to expand and contract - if pressed against a flat surface or cavity it turns it into a speaker!

Tools & Supplies
Soldering Iron
Wire Strippers
3D Printer

Parts
Bone Conductor Transducer
150mAh Lithium Ion Polymer Battery
Stereo Headphone Jack
Slide Switch
JST Battery Ext. Cable

Check out the full tutorial on the Adafruit Learning System

The enclosure is a three piece design that snap-fit together. The bonebox-top.stl part houses the slide switch and audio input jack. The bonebox-case.stl part houses the amplifier and lithium polymer battery. The bonebox-bottom.stl part houses the bone conductor transducer exposing the vibrating metal piece but is secured in place with built in clips on the bottom part.

The parts are optimized to slice with MakerWare and printed using PLA with no raft or support material.