Help to to build the perfect bluetooth talking device

I am here to to discuss one of my problems that I am currently facing. So I was working on a project in which I wanted to create a bluetooth talking device for helmets. Recently I have noticed that China is making the most helmet intercoms and they are selling them at a very huge price. My aim is to make a version which will last long, will have bigger battery life and better sound clarity and mainly with a lower cost.

So coming to the point, let me discuss what I have done already. I have selected a basic bluetooth receiver which costed me very less and then I bough one pair of speakers and a 3.5 mm head phone jack. I have connected the head phone jack with the speakers with wires and made a simple bluetooth talking device as the bluetooth adapted already had a micro phone build inside. The quality of the micro phone is superb so I do not have any problem with that. So I tested it for one day and observed that it gave me 60 minutes of continues music after charging it fully. The first problem that I faced is that the sound was too low. So I bought another pair of good quality loud headphone and connected with the adapter again. The sound increased dramatically but now what I faced is that the battery backup decreased a lot.

I opened up the adapter and took a look at the battery. I saw that there was a tiny battery inside wrapped with a white plastic cover. Now what I am thinking is that why dont I increase the battery or do something which will increase the battery backup. I first though to make a power bank with a samsung charger which has 3000 mah of battery. By this we do not have to charge the adapter for at least 1 week. The reason of choosing a phone battery is that it is slim and will easily get fitted inside the foam of the helmet. Then I realised that making a power bank would require a chip which nay not fit inside the foam of the helmet. Many if you would think that why not using a device which will hang outside the helmet as regular intercoms. So for that I must say that my project is to build a device which will stay inside the helmet. As many bikers fall down and the device gets broken and this is not very pleasing.

So as the power bank concept is not happening until I find a chip which is as slim as the battery I cannot continue with this project. So then I came up with another idea. I though why not buying another bluetooth adapter and take out the battery and join the battery to the other battery in series. I tried it but the other battery is nit fitting inside the tiny adapter.

I am posting this to get some help as I have no more ideas of how to increase the battery backup of this tiny adapter. Please people who deals with micro controllers must know this factor. Help me out here.

Hi,

and will easily get fitted inside the foam of the helmet.

Click to expand...

Sadly the foam of the helmet is a part of the protection system.
Thus I´d not buy such a modifed helmet. Safety is more important for me than the talking device inside the helmet.

The rest of your information is just vague.
What does
* "tiny"
* "as slim as"
* "not fitting inside"
mean?

Why not giving values with units instead?

For example: When you say you need a form factor of 10mm x 40mm x 50mm every one in the world can imagine the same size.

Klaus