Hi Alex, The datasheet (Page No: 11) of CC2420 says “ The range for RSSI is approximately from –100 dBm to 0 dBm “. Page No: 49 of CC2420 datasheet talks about substracting the offset value, -45 to get the dBm equivalent. Page No: 10 of datasheet talks about the Receiver Sensitivity (Typ: -95 dBm).
Your previous readings shows approx. 0 dBm (when both the motes placed very close) Try to increase the distance between the motes. When they get disconnected, the Rssi Message received on your PC will be close to -50 ( so that -50 -45 = -95dBm) ( I am getting this value). Thus I believe subtracting -45 is enough. Thanks Jobish John On Sat, May 9, 2015 at 10:37 AM, Alex Cp <[email protected]> wrote: > Hi all. > > Im trying to convert in dBm the values obtained from the app: > > <http://tinyos.stanford.edu/tinyos-wiki/index.php/Rssi_Demo> > > In my case appears the next values: > > Rssi Message received from node 1: Rssi = 40 > Rssi Message received from node 1: Rssi = 41 > Rssi Message received from node 1: Rssi = 40 > Rssi Message received from node 1: Rssi = 40 > Rssi Message received from node 1: Rssi = 41 > > Because is very close both motes TelosB (Sending Mote and Rssi Base ) > > In the TinyOS tutorial appears the next: "...that this app prints only the > raw RSSI values ..." > > On the other hand I have the Data sheet of the RF Transceiver CC2420: > > <http://web.stanford.edu/class/cs244e/papers/cc2420.pdf> > > But is not clear to me How I can do the conversion from raw RSSI to dBm. > > > I read, someone in the TinyOS mail-list, who wrote that is only necessary > substract -45: > > < > https://www.millennium.berkeley.edu/pipermail/tinyos-help/2014-March/058162.html > > > > But I suppose is not a exact calculation. > > I'll be grateful if somebody can generously explain how is the correct way > to convert raw RSSI values from a TelosB to a dBm. > > Thanks in advance. > > Alex. > > > Date: Mon, 3 Mar 2014 12:13:27 +0530 > From: ashok <[email protected]> > Subject: [Tinyos-help] RSSI DEMO > To: [email protected] > Message-ID: > <CAKs3p-d4GxW_dJjVc9Hwmk-+X_ZKi+hnvzCr+C2TS2NkuKg4uA@mail. > gmail.com> > Content-Type: text/plain; charset="iso-8859-1" > > Dear All, > > I am getting RSSI value in tinyos like: > > Rssi Message received from node 1: Rssi = -14 > Rssi Message received from node 1: Rssi = -1 > Rssi Message received from node 1: Rssi = 2 > Rssi Message received from node 1: Rssi = -2 > Rssi Message received from node 1: Rssi = 2 > Rssi Message received from node 1: Rssi = 0 > Rssi Message received from node 1: Rssi = -2 > Rssi Message received from node 1: Rssi = 2 > Rssi Message received from node 1: Rssi = 2 > > and I want to conform that is this value is in Dbm? > > if not than how can i convert it? > > regards, > > -ashok > > _______________________________________________ > Tinyos-help mailing list > [email protected] > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help >
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