[Tinyos-help] %5BTinyos-help%5D%20%3D%3Futf-8%3Fq%3FRssiDemo%3D3A_packets_are_there_but_RSSI%3D3D%3F%3D%0A%09%3D%3Futf-8%3Fq%3F0%3F%3D&In-Reply-To=

[Andrey Gursky]

Hi Miklos!

> 
> Please use the RF230 datasheet for the exact meaning of the measured
> ED_LEVEL. Minimum value is 0 = less than -91 dBm, maximum value is 84,
> one unit corresponds to 1 dB, typical accuracy: +-5 dB which should be
> a constant calibration error. You cannot reliably calculate the
> distance from the measured RSSI values.

Thanks for advice! It has helped me. The range is really big enough, but 
the step of 3 dB is also too big. But if you say that the accuracy is
+- 5 dB, so I haven't worry about these big steps. I've realized now 
that there is no chance to build a small application, that demonstrates 
localization based on RSSI.

Andrey


> 
> On Thu, Jun 19, 2008 at 1:01 PM, Andrey Gursky <andrey.gursky at online.ua> wrote:
>> Hi!
>>
>> Sorry, I misunderstood the meaning of RSSI values. So if I'm bringing 1 mote far away and it must increase it's transmission power to maximum, than after some distance I can't distinguish any more between distance changes, however the packets are well transmitting. It's sad that it becomes so early.
>>
>> Andrey
>>
>>
>>> I've tried the RssiDemo on IRIS platform. I set up the smallest transmission power in Makefile:
>>>
>>> PFLAGS+=-DRF230_DEF_RFPOWER=15
>>>
>>> If I place 2 motes very close to each other I get approximately 30 (HEX),
>>> but if I place motes enough away I still can see net.tinyos.tools.Listen gets
>>> packets but RSSI is 0.
>>>
>>> Is there something I have to pay attention (scaling?) or the RF230 chip have a small resolution
>>> for RSSI values?
>>>
>>> Andrey
>>>
>> P.S. Sorry, if my answers are still being posted as new thread.
>> I click on answer/answer all button in the web interface of my mail server,
>> and I'm not changing the topic, but something goes wrong :(
>> Maybe any advices?
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>>
> 
>