Bluetooth Bone Conduction Glasses

The purpose of this instructable is to make an attachment that is cheap, works like a bluetooth earphone, uses bone conduction technology, has no visible cables, looks good (doesn't make you look like a cyborg at least) and could be fitted on almost any glasses (might need modifications for the specific glasses).

- Bluetooth earphones (I just bought a very cheap one online)

- An amplifier circuit (The smallest one possible) PAM8403 works well.

- A bone conduction module (We need the smallest one in this case too which is the gd02 model but others will work just fine) Bone Conduction Module

- A small Li-Po battery. (I bought a 250mAh Li-Po battery online)

- A 3d printer (Optional if you want to make the case out of another material)

- We will also need some tools to work with like a soldering iron and a cutting plier.

Just a reminder that we will be soldering at a small scale and it might be dangerous sometimes. You can burn your fingers etc. (speaking from experience) so be careful while soldering.

And these are the only things we need!

So before we start i want to inform you a little bit on how bone conduction technology works and how we are going to apply it.

Conduction of sound through the human skull was first discovered by Ludwig van Beethoven in the 18th century. Since he was almost deaf he found a way to hear music through his jawbone by biting a rod attached to his piano. After this discovery more people started working on this and today we have very tiny bone conduction modules available for any customer.

These bone conduction modules work just like traditional speakers but instead of vibrating the air they are designed to vibrade solids. (For our case its human bones but it can also vibrate any solid and turn it into a speaker) The bone conduction module i have found is called GD02 Bone Conduction Module (Listed in supplies section) and if i am not wrong it is the tiniest bone conduction module available on the market. So we are going to use this GD02 module and make a case that is big enought to fit all the circuit and the battery. My high school has a 3d printer so i am going to use it for the casing but if you want to, you can make it out of another material like wood although i think 3d printing is the easiest option. Another thing is even though i will be sharing the stl files you might want to adjust them so they fit your own glasses.

Since this attachment is going to be mounted on the side of a pair of glasses, the bone conduction module will be touching the temporal bone and thus conducting sound to our ear. This also means it's only going to be working on the right side and will only get right side signals from our phone. I am not going to make a stereo version of this but it could easily be done by making another one of the same module for the left side.

STL Files

So i 3d printed the casing because it was the easiest option for me but as i've said before you can make it in any other way you want to.

We have to make sure it has the right dimensions to fit all your circuitry and the battery. I made it in 2 pieces that snap into each other so it's easier to remove the cap. Also the part that snaps also holds the side of my glasses so it stays in place tightly.

There is also a hole on the side which my bluetooth circuit's buttons come to. This hole is for allowing me to add a small button to turn the module on and off(Also pausing and resuming songs etc.) And there is a hole under the case which the bluetooth module's microUSB input corresponds to. That USB port will be used for charging.

You can measure the dimensions of your components and make the case before soldering but it will be a good idea to solder everything together, make sure it works and then make a case accordingly.

Now we can get to the building instructions.

First we disassemble our bluetooth earphones to take out the bluetooth circuit and the battery inside. It's usually very easy to open a bluetooth earphone with your nails or using something sharp.

After that we will desolder the earphone cables because we'll be soldering new wires that will go the amplifier. Also desolder the battery because this battery has very low capacity and is not suitable for what we are going to make (Unless you've bought earphones with higher capacity than 100-150 mAh). You can use the battery and the earphones for many other projects.

First you will have to solder 2 wires to the bone conduction module. Depending on the model you bought it might come with cables or it might not. If it doesn't have cables on it you can easily solder 2 to solders pads on the back of the module.(Picture 2) Also the polarity of the GD02 module doesnt matter. This means you can connect any of it's cables to negative or positive outputs of the amplifier.

After that you will have to solder all the components to each other according to the schematic above. Be careful while soldering on the bluetooth circuit because it might be sensitive (Especially if it's a cheap one)

Try to use short wires so that they don't make a mess in the casing.

After soldering the components, it's time to put them in the casing. Since it is small, it was a little hard to put them in but i managed to do it. You can see above what it looks like with all the components inside.

I haven't (yet) put a button in the button hole but i will do it when i 3d print one.

After assembling all the stuff, it's time to attach it to a pair of glasses and test it!

It fits nicely on my glasses and feels nice while wearing it. Since i haven't put a button on it yet i cant control the music without taking my glasses off but this will be fixed.

My phone sees the bluetooth device and it works well. The sound quality is better than i expected it. Especially when the bass hits you really feel it in your head. It sometimes makes a weird noise but it's probably because of the cheap bluetooth module. (And maybe the amplifier but im not sure) But this noise doesn't bother me too much because it's actually very low and happens rarely. It's still something to fix in the future.

Now since i won't be able to show how it sounds when i put it on, instead i'm going to show you how it sounds when it's used as a speaker. Video is above.

All things considered it was a fun project to make and i think it has great potential. From people who have hearing problems to people who just want to make their own wearables it could be used by a lot of people. Also it is easy and cheap for everyone to build. (Overall it doesn't cost more than 20$)

I would call this project a success but it still has so much room for improvement and i'm certainly going to improve it. If you have any suggestions or questions you can ask me in the comments section of this instructable.

Thanks for reading through and stay creative!