Re: [Tinyos-help] calibrating TMote Sky sensors???
Hello, Are the batteries on both motes supplying at least 2.4V? If it falls below, the readings will be different from what they should be. The SHT11's otherwise are calibrated by Sensirion at the factory, that's why they cost what they do! Simon Davis On Tuesday 29 August 2006 09:55 am, Luis E. Palafox-Maestre wrote: Hi, Is there a way of calibrating the onboard sensors on the TMote? I'm asking this because I keep getting different readings for motes that are next to each other, for instance I consistently get temperature readings that are up two Celsius degrees apart. -- ___ Play 100s of games for FREE! http://games.mail.com/ ___ Tinyos-help mailing list Tinyos-help@Millennium.Berkeley.EDU https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
Re: [Tinyos-help] calibrating TMote Sky sensors???
As per the Tmote Sky datasheet, you need to calibrate the internal temperature sensor. A one-point calibration provides adequate results, although I recommend a two-point calibration. You will need a known good reference and two different controlled temperature environments--such as room temperature and a refrigerator. Search google for more info on calibration. -Joe On 8/29/06, Luis E. Palafox-Maestre [EMAIL PROTECTED] wrote: Hi, Is there a way of calibrating the onboard sensors on the TMote? I'm asking this because I keep getting different readings for motes that are next to each other, for instance I consistently get temperature readings that are up two Celsius degrees apart. Regards, Luis Enrique Palafox Maestre Phd Student Computer Science Department CICESE Research Center Ensenada, B.C., Mexico ___ Tinyos-help mailing list Tinyos-help@Millennium.Berkeley.EDU https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help ___ Tinyos-help mailing list Tinyos-help@Millennium.Berkeley.EDU https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
Re: [Tinyos-help] calibrating TMote Sky sensors???
On Tuesday 29 August 2006 09:55 am, Luis E. Palafox-Maestre wrote: Hi, Is there a way of calibrating the onboard sensors on the TMote? I'm asking this because I keep getting different readings for motes that are next to each other, for instance I consistently get temperature readings that are up two Celsius degrees apart. Tmote uses the Sensirion SHT11, which is factory calibrated. It's data sheeet says its accuracy is +/- 0.4C @ 25C. I'm assuming the two motes are identical, sampling the sht11 at the same rate, and generally performing the same workload? Self-heating is a real issue; see the data sheet for more info. Sorry if this is too obvious, but environmental factors can be a pretty big deal. I just got a temp increase of 1.22C on the mote (not Tmote, but uses sht11) at my desk after moving it ~ 8 closer to my monitor. If you haven't already, you might try your test again, then swap the motes' positions and see what happens. Because the sht11 is tied thermally to the mote, it can take quite several minutes for temp readings to fully stabilize after a change. Steve ___ Tinyos-help mailing list Tinyos-help@Millennium.Berkeley.EDU https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
