Connecting to Bluetooth Low Energy devices

Connecting to Bluetooth Low Energy devices

[Philipp Claves]

Hello

Trying  to get started with Bluetooth Low Energy devices, i used hcitool and 
gatttool to enumerate device attributes, but did not get far:

# hcitool lescan
LE Scan ...
<MAC-Device1> Battery V1.0
<MAC-Device1> (unknown)
<MAC-Device2> Battery V1.0
<MAC-Device2> (unknown)
^C

# gatttool -b <MAC-Device1> -I
[   ][<MAC-Device1>][LE]> connect
Connecting... connect error: connect error: Connection refused (111)
[   ][<MAC-Device1>][LE]>

This is all i get.

The devices are Nordic Semiconductor nRF8001 based and currently run a simple 
BTLE demo application by Nordic Semiconductor. It does not use bind/paring but 
simple connect. Unfornately that doesn't seem to work.

The host uses an of-the-shelf USB Bluetooth 4.0 Stick with a Broadcom 
BCM20702A0 Chip inside.

Am i doing something obviously wrong?
Any tips where to get more information about the error (dmesg shows nothing)?

Regards
Philipp Claves

-- 
Budelmann Elektronik GmbH
Von-Renesse-Weg 60
48163 Münster
Germany

Tel.  +49 (0)2501 9208440
Fax   +49 (0)2501 5887024
claves@budelmann-elektronik.com
www.budelmann-elektronik.com

Re: Connecting to Bluetooth Low Energy devices

[Anderson Lizardo]

Hi Philipp,

On Thu, Sep 13, 2012 at 11:34 AM, Philipp Claves
<claves@budelmann-elektronik.com> wrote:
> Hello
>
> Trying  to get started with Bluetooth Low Energy devices, i used hcitool and
> gatttool to enumerate device attributes, but did not get far:
>
> # hcitool lescan
> LE Scan ...
> <MAC-Device1> Battery V1.0
> <MAC-Device1> (unknown)
> <MAC-Device2> Battery V1.0
> <MAC-Device2> (unknown)
> ^C
>
> # gatttool -b <MAC-Device1> -I
> [   ][<MAC-Device1>][LE]> connect
> Connecting... connect error: connect error: Connection refused (111)
> [   ][<MAC-Device1>][LE]>
>
> This is all i get.

Which kernel version are you running?

> Am i doing something obviously wrong?
> Any tips where to get more information about the error (dmesg shows nothing)?

run "hcidump -X" and check the logs while you run "hcitool lescan".
Then check the type of advertising those devices are sending. They
should be connectable advertisings to be able to connect to them. Also
check the address type, if it is "Random" you need to pass "-t random"
to gatttool.

Regards,
-- 
Anderson Lizardo
Instituto Nokia de Tecnologia - INdT
Manaus - Brazil

Re: Connecting to Bluetooth Low Energy devices

[Philipp Claves]

Hi Anderson

On Thu, Sep 13, 2012 at 12:54:26, Anderson Lizardo wrote:
> Hi Philipp,
> 
> On Thu, Sep 13, 2012 at 11:34 AM, Philipp Claves
> 
> <claves@budelmann-elektronik.com> wrote:
> > Hello
> > 
> > Trying  to get started with Bluetooth Low Energy devices, i used hcitool
> > and gatttool to enumerate device attributes, but did not get far:
> > 
> > # hcitool lescan
> > LE Scan ...
> > <MAC-Device1> Battery V1.0
> > <MAC-Device1> (unknown)
> > <MAC-Device2> Battery V1.0
> > <MAC-Device2> (unknown)
> > ^C
> > 
> > # gatttool -b <MAC-Device1> -I
> > [   ][<MAC-Device1>][LE]> connect
> > Connecting... connect error: connect error: Connection refused (111)
> > [   ][<MAC-Device1>][LE]>
> > 
> > This is all i get.
> 
> Which kernel version are you running?
Linux 3.5.3
Which is the minimum version required?

> 
> > Am i doing something obviously wrong?
> > Any tips where to get more information about the error (dmesg shows
> > nothing)?
> run "hcidump -X" and check the logs while you run "hcitool lescan".
> Then check the type of advertising those devices are sending. They
> should be connectable advertisings to be able to connect to them. Also
> check the address type, if it is "Random" you need to pass "-t random"
> to gatttool.

Thanks, -t random did the trick.
But it's still strange, the device addresses never changed even once while 
working with them. The bluetooth SIG talk about LE adresses mentioned random 
adresses to change every 15 minutes or so....
I need to investigate this more.

Thanks for your help!


Philipp Claves
-- 
Budelmann Elektronik GmbH
Von-Renesse-Weg 60
48163 Münster
Germany

Tel.  +49 (0)2501 9208440
Fax   +49 (0)2501 5887024
claves@budelmann-elektronik.com
www.budelmann-elektronik.com

Re: Connecting to Bluetooth Low Energy devices

[Anderson Lizardo]

Hi,

On Fri, Sep 14, 2012 at 4:55 AM, Philipp Claves
<claves@budelmann-elektronik.com> wrote:
>> Which kernel version are you running?
> Linux 3.5.3
> Which is the minimum version required?

If you run a too old kernel with a recent bluez, bluez will complain
(due to mgmt channel change), so I think this version is fine.

> Thanks, -t random did the trick.
> But it's still strange, the device addresses never changed even once while
> working with them. The bluetooth SIG talk about LE adresses mentioned random
> adresses to change every 15 minutes or so....
> I need to investigate this more.

This behavior depends on which random address type is used.

static random addresses are not required to change. Some (all?)
devices change their static random address when battery is removed.

private random addresses need to change periodically to avoid tracking.

Regards,
-- 
Anderson Lizardo
Instituto Nokia de Tecnologia - INdT
Manaus - Brazil