You may get a more informed opinion, but my belief is that the raw RSSI reading should track the battery voltage because both the source and ADC reference are relative to the battery. This would not be the case if the ADCref was regulated, but it's not. So baring any non-linearities you shouldn't need to account for battery droop when calculating actual RSSI.
To get a really real RSSI value you would have to calibrate and adjust the "battery-voltage" used in the VRSSI formula. But using a nominal 3v in all calculations will allow everyone to agree on a relative standard. MS Agnelo Silva wrote: > I am preparing the code to make the conversion of the "raw" RSSI value > available in received message (indirectly a reading from ADC INPUT 0 - > RSSI MONITOR). Although, I am developing using T1 (TinyOS 1.x), I read > the T2 doc http://docs.tinyos.net/index.php/Rssi_Demo and noted the same > thing I observed in some examples I saw in the Internet: what are about > the battery reading for each message? > > I understood that, according to the manufacturer manual, VRSSI = 'raw > counts' * battery voltage / 1024. So, for me, the correct code must > present a reading of the battery before sending any 'raw RSSI' for > conversion. > > Also, sometimes, I saw in some codes/messages, a direct use of '3' in > the place of "battery voltage". Reading the schematic of the Mica2, I > didn't see any voltage regulator to make such assumption and I am not > sure about this approach considering the CC1000 data sheet. > > So, what I have in mind is to develop the algorithm to send informations > to a certain procedure (internal function for locally conversion or > external program): > 1) First reading: send (battery level, raw RSSI) > 2) Next reading: if the battery level doesn't change according to a > certain threshold, send (raw RSSI) > 3) Next reading: if the battery level does change according to a > certain threshold, send (new battery level, raw RSSI) > > Please, I would like to hear if I misunderstood the topic "at all" or, > if not, I would like to hear different solutions or suggestions. > > []s, > Agnelo R. Silva > > > > ------------------------------------------------------------------------ > > _______________________________________________ > Tinyos-help mailing list > [email protected] > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
