I think the user guides for the various Motes have some information about the battery voltage measurement. However the Battery components seem to vary across platforms and TOS versions. I haven't payed much attention to them so I can't help with that more. Try searching this list for battery measurement info.
One rather arcane thing you should know is that, on the mica's at least, the "battery" measurement made by ADC7 is actually from a fixed voltage reference chip and the reference value (the max value you can convert) is the actual battery voltage. So the value you get RISES as the battery ref drops. I believe the Battery software components adjust for this, which makes them very hard to understand. If you're confused about the conversion resolution I gave below let me know where you got lost and I'll try to make it clearer. I just guessed at the accuracy based on the fact that the bottom couple of bits from the onboard converters are usually not very stable. MS Flavio Pompermaier wrote: > thank for the reply. However is there any documentation about this > calculation? I have not well understood the part regarding the noise and the > conversion to millivolts.. > > Michael Schippling ha scritto: >> The ADCs used are either 10 or 12 bits, depending on the controller. >> That's either 3/1024 volts for the micas or 3/4096 volts for the tmotes. >> I think some of the Battery components convert the value to milli-volts, >> but there's some noise involved so the actual accuracy is likely ~10 mV. >> MS >> Flavio Pompermaier wrote: >>> Hi to all, >>> is there anyone that knows the accuracy of batteries voltage measurement? >>> Is it in the order of millivolts or microvolts? Or what? >>> >>> Best regards, >>> Flavio >>> >>> >>> ------------------------------------------------------------------------ >>> Tante idee per la salvaguardia del pianeta su >>> Yahoo! for good >>> <http://us.rd.yahoo.com/mailuk/taglines/isp/control/*http://us.rd.yahoo.com/evt=52436/*http://it.promotions.yahoo.com/forgood/environment.html>. >>> >>> >>> >>> >>> ------------------------------------------------------------------------ >>> >>> _______________________________________________ >>> Tinyos-help mailing list >>> [email protected] >>> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help >> -- >> Platform: WinXP/Cygwin >> TinyOS version: 1.x, Boomerang >> Programmer: MIB510 >> Device(s): Mica2, MicaZ, Tmote >> Sensor board: homebrew > > > > Tante idee per la salvaguardia del nostro Pianeta su Yahoo! For Good > http://it.promotions.yahoo.com/forgood/environment.html -- Platform: WinXP/Cygwin TinyOS version: 1.x, Boomerang Programmer: MIB510 Device(s): Mica2, MicaZ, Tmote Sensor board: homebrew _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
