Second this: there are a thousand things that can go wrong and irrevokably cost money. You need to get that production expertise in somehow, either by hiring or consultancy.

It's possible to learn a lot from people like Bunnie Huang, such as his "Chumby" product which he blogged the development of.

Thanks, I'll check on this guy and his project

Not always the case - I fit this profile and made it to the other side (lifeclockone.com) - OP feel free to reach out and I’d be happy to share my experiences and help out if I can.

Thanks, very interesting!

Thanks for your comment. I want to make up my mind around what's needed to go through this project. I envision it as a toy project on the prototyping/layout side, then find partners for other steps. I guess there exists companies to outsource stocking and delivery.

Can you describe what product or just hardware(hw features) you want to build without sharing any secrets ?

That will help people around here guide you towards a good way to prototype it.

Because there may be a way to prototype what you want without knowing much about hardware design.

Sure! I want to build a wristband that need a flexible rechargeable power source and to be programmed by bluetooth

The battery won't be flexible. You can have multiple batteries with flexible connections but they'll be a likely point of failure. Will you really need that much power? Bluetooth LE really is "low energy" as are many sensors. If it's supposed to make a lot of light, noise, has a motor, or use more powerful RF like WiFi, then the power requirements will be greater.

You've already be directed to Adafruit which is a great resource, not just as a store and product developers in their own right but for all their learn materials and years worth of weekly videos. Here's a breakout board for charging their little LiPo batteries via MicroUSB.

https://www.adafruit.com/product/1904

I guess I got a lot to learn before answering the requirements question :/ Thanks for the link !

So, something very similar to fitness trackers and smartwatches? As others have pointed out, no flexible power sources; realistically you're going to end up with a single SoC that already has bluetooth, such as the Nordic Semiconductor ones.

Most of these devices have on-demand displays to save power.

Miniturising it and making the casework function is the hard part. You might be able to build a "desktop" version of it fairly easily..

Yes, like a fitness tracker but with tissue. I don't even know if it's possible to combine lithium batteries and tissues :/

What do you mean by flexible ?

As for the wristband, have a look at hexiwear, and the hexiwear battery pack(which may be wearable). it has BLE and it does support "Firmware Over the Air update", i think.

In my mind, it was something like that :

https://news.panasonic.com/global/press/data/2016/09/en16092...

Flexible batteries you can embad in a tissue wristband for example. But I don't know if it's possible to do so.

Thanks for the link I will check it out asap.