2010/10/5 Marcel Holtmann <marcel@xxxxxxxxxxxx>
>
> Hi Giedo,
>
> > I'm working on a bluetooth program with some sort of distance sensing/tracking.
> > To make this easier I came across a feature called inquiry_with_RSSI.
> > Could somebody tell me what kind of dongles support this feature. I
> > mean, does every 2.1 BT dongle support it, or can you only find out
> > once you get one in your hands?
>
> in general every Bluetooth 1.2 dongle and later should support Inquiry
> with RSSI. I still have to come across a 2.1 dongle that doesn't.
>
> Regards
>
> Marcel
>
Hello Marcel,
Thanks for your fast response.
I got myself a brandless bluetooth 2.1 dongle (at least, that's what
is says on the box).
In hciconfig I got something about HCI version 2.0:
HCI Version: 2.0 (0x3) Revision: 0x44
LMP Version: 2.0 (0x3) Subversion: 0x3
Manufacturer: Cambridge Silicon Radio (10)
Does that mean it is a BT 2.0 device?
I would like to ask a second question:
When I put the device in inqmode 1, (the dongle has the feature
inquiry with rssi; I checked with hciconfig hci0 features)
Inquiry mode: Inquiry with RSSI
I get 'Inquiry result with RSSI'-events. But these events have a
constant RSSI value.
I would like know if this is a known bug, or if there is a setting I
have to set.
This is a little hcidump output:
> HCI Event: Inquiry Result with RSSI (0x22) plen 15
01 5C 07 D3 D7 23 00 01 02 04 02 5A 7E 70 00
> HCI Event: Inquiry Result with RSSI (0x22) plen 15
01 1C 01 00 81 1F 00 01 02 04 01 02 40 7E 00
> HCI Event: Inquiry Complete (0x01) plen 1
00
> HCI Event: Inquiry Result with RSSI (0x22) plen 15
01 5C 07 D3 D7 23 00 01 02 04 02 5A 7E 70 00
> HCI Event: Inquiry Result with RSSI (0x22) plen 15
01 89 99 66 D0 25 00 01 02 0C 02 5A 61 15 00
> HCI Event: Inquiry Complete (0x01) plen 1
00
> HCI Event: Inquiry Result with RSSI (0x22) plen 15
01 1C 01 00 81 1F 00 01 02 04 01 02 3F 7E 00
> HCI Event: Inquiry Result with RSSI (0x22) plen 15
01 5C 07 D3 D7 23 00 01 02 04 02 5A 7D 70 00
> HCI Event: Inquiry Result with RSSI (0x22) plen 15
01 89 99 66 D0 25 00 01 02 0C 02 5A 61 15 00
> HCI Event: Inquiry Complete (0x01) plen 1
00
If I'm correct the RSSI value should be the last octet, which is always 0.
I've tested also with another bluetooth dongle, this was a 2.0 BT
dongle also with the inquiry with rssi feature. That dongle gave me
(valid) RSSI values in the returned events between -40 and -90.
The last dongle is not longer in my possession, so I would like to fix
the first one.
Regards,
Giedo
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