Re: [Bluez-users] Best way to communicate with hidden devices

[Stephen Crane <jscrane@maths.tcd.ie>]

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On Wed, 2005-09-14 at 10:32 -0600, Noel Paz wrote:
> I have a BT weight scale and I want to communicate to it. Problem is I 
> think it is set to be un discoverable.  According to it's scant 
> documentation it uses the BT serial protocol and a 128 bit encyrption 
> and a PIN. - that it expects to start communication.  Supposedly, after 
> it weighs something,  it tries to find an ACCESS point, see if the 
> Access Point has the same PIN and if it does it transmits data packets 
> which are very discrete

This sounds like a very strange way of doing things. I'm sure they had
their reasons though.

> hcitool --scan and sdptool --browse cannot find it (yes I have made sure 
> it can find other devices). I've turned hcidump too too make sure I can 
> sniff it but to no avail

What did you browse for?

> Honestly, I am new to BlueZ and have been devouring as much 
> documentation as I can. My thoughts are setting up a PAN with an access 
> point role using rfcomm. If anybody has worked on one way traffic 
> bluetooth devices, let me know. I really have no way of knowing whether 
> this weight scale  has a broken radio, although I can experiment with 
> making my other devices undiscoverable with a PIN. Unfortunately their 
> support is for Windoze only and require you to buy a container full of 
> weight scales before their engineers will talk to you.

I did a bit of experimentation with a GPS device, documented here:
http://www.maths.tcd.ie/~jscrane/gps/

As described, this device provides a service to which you must connect
before it will spit out GPS data.

> BTW there is a little sticker which seems to be the bdaddr.

You could try running l2ping against that bdaddr: that should tell you
if its working.

Steve
-- 
Stephen Crane <jscrane@maths.tcd.ie>

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