Hi Yusnaidi, The value shown by the Java application are the RSSI value read by the receiving node, that is a value generated by the radio chip according to its datasheet. Because the value is calculated by using signal strength it is influenced by the output power settings of the transmitting node, but it depends also on many others environment factors: distance, multi-path, fading, and so on, for further investigation I would suggest you to look at the paper [1] were Figure 2 shows how the RSSI changes even if the distance between nodes do not change. If you want to convert the value shown by java to the dBm value you have to look at the datasheet of the radio chip that is used by your nodes. For example, in case of the IRIS which uses the AT86RF230 radio the return value should be decrease by 91, thus if the java application running on an IRIS shows 35 it means that the received value is -56 dBm.
Best regards, Stefano "Kismet" Lenzi [1] - http://wnlab.isti.cnr.it/paolo/papers/ICC09-Final.pdf On Wed, Jun 16, 2010 at 14:34, Yusnaidi Md Yusof <yusnaid...@gmail.com> wrote: > Hi All, > > I need a help here. I have gone through the RssiDemo application and able to > observe the RSSI value. > > Some of the values I got were: -9, -20, -10, 0, etc. I am just wondering is > it this value represents the output power value sent by the sending motes? > If so, is the value is in dBm format? I have checked with the Output Power > Programming settings in the Chipcon CC2420 datasheet (rev 1.2), 2004-06-09, > page 50. The table shows the output power settings and typical current > consumption of the 2.45GHz radio. Some of the values of the Output Power in > the table are: 0, -1, -3, -5, -7, -10, -15, and -25. > > Thus, are these values represents the similar value I got from the RssiDemo > application (I am using the micaz motes)? If not, is there any reference can > I refer to translate the equivalent output power (in dBm) from the values I > got? > > Many thanks in advance for any kind help. > > Yusnaidi > > _______________________________________________ > Tinyos-help mailing list > Tinyos-help@millennium.berkeley.edu > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help > _______________________________________________ Tinyos-help mailing list Tinyos-help@millennium.berkeley.edu https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
