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From:   Alain Michaud <alainmichaud@google.com>
Date:   Tue, 26 May 2020 15:25:24 -0400
Message-ID: <CALWDO_WbKxyWgM9A-9XSCqDtc2uXnLOANiswS-8TEzCR=PoRrg@mail.gmail.com>
Subject: Re: UUIDs for every single physical peripheral's service and characteristics?
To:     Christopher de Vidal <cbdevidal.jk1@gmail.com>
Cc:     BlueZ <linux-bluetooth@vger.kernel.org>
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Yes.  Unless each of your 1000 devices will have a different
protocol/contract to interact with them, you don't need to have unique
UUIDs for the services/characteristics per device instance.

On Tue, May 26, 2020 at 12:22 PM Christopher de Vidal
<cbdevidal.jk1@gmail.com> wrote:
>
> So let me make sure I understand. The devices themselves have their
> own Bluetooth addresses (similar to MAC addresses, I don't know the
> proper term) which are unique among every physical device sold. And
> also there is one (and only one) service UUID which is shared among
> all 1,000+ peripherals which I sell, and 19 characteristic UUIDs that
> are shared among the physical peripherals. The devices come with their
> own Bluetooth "MAC" and I only need to obtain 20 UUIDs in total for
> the product line. Did I get that right?
>
> Christopher de Vidal
>
> Would you consider yourself a good person? Have you ever taken the
> 'Good Person' test? It's a fascinating five minute quiz. Google it.
>
> On Tue, May 26, 2020 at 10:57 AM Alain Michaud <alainmichaud@google.com> wrote:
> >
> > Hi Christopher,
> >
> > The term "unique" will vary based on context.  In the context of a
> > Gatt Service and Characteristic, it is intended to uniquely identify
> > the "contract" defined by the service/characteristics.  For example a
> > Temperature Service would have a UUID that universally defines the
> > contract/interface defined by that service.
> >
> > So for your custom service, you'll need to define a set of 20 128 bit
> > UUID (16 bit uuids are reserved for SIG defined uuids) that uniquely
> > identify the contract that's defined by your service/characteristics.
> > The devices can uniquely be identified/addressed by their respective
> > addresses.
> >
> > I hope this is helpful.
> >
> > Thanks!
> > Alain
> >
> > On Tue, May 26, 2020 at 10:38 AM Christopher de Vidal
> > <cbdevidal.jk1@gmail.com> wrote:
> > >
> > > Help a newbie? I'm seeking to build a niche product for sale, a
> > > Raspberry Pi-based device which during the initial setup acts a BLE
> > > peripheral. (Python using dbus to Bluez.) It has a single service and
> > > 19 characteristics. I get that the first "U" in UUID stands for
> > > unique. Must that be unique among each physical product, or may it be
> > > unique among the product line?
> > >
> > > So if I sell 1,000 units (which would be a success), would I need to
> > > obtain 1,000 service UUIDs and 19,000 characteristic UUIDs? Or just 20
> > > total, for the entire product line?
> > >
> > > The goal is so that the iOS/Android app can have that pre-set in the
> > > code and quickly discover the device, pair it automagically.
> > >
> > > I suppose the risk is of a conflict of two similar devices which are
> > > in the same vicinity of the phone, and both set into peripheral mode
> > > at the same time. But that would be a minimal risk which I could
> > > accommodate for.
> > >
> > > Christopher de Vidal
> > >
> > > Would you consider yourself a good person? Have you ever taken the
> > > 'Good Person' test? It's a fascinating five minute quiz. Google it.