How do you deal with the huge changes in current (10 milliamps to 10 microamps), or deal with the corresponding large jumps in voltage at the oscilloscope/voltmeter? With an oscilloscope that can manage two millivolts per division, and a 220 ohm sense resistor, 10 microamps should give you a 2 mV difference across resistor, while at approx 10 milliamps (start-up current) you will get almost a 2 volt difference? We tried to overcome this by using a schottky diode bypass for the start up current, but I am still getting current readings in the 100 plus microamps region, that are not in line with the expected sleep current for null (five microamps). A problem of dealing with these huge variations affects the use of ammeters as well. Exactly what sort of set up should I be using to get these five microamps readings that everybody is posting? Sense resistor values, oscilloscope scales, ammeter sensitivities, etc would be very useful! Thanks very much in advance! -Ben
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Jacob Sorber Sent: 16 August 2007 06:14 To: SANG Junjun Cc: tinyos-help@Millennium.Berkeley.EDU Subject: Re: [Tinyos-help] The power consumed V=IR (Ohm's Law) Put a low tolerance sense resistor (typically low resistance) in series with the battery, and measure the voltage drop across the resistor. That will tell you how much current (I) is going through the circuit. You will also need to measure the battery voltage. Then P=IV gives you the power draw. You will need some way of logging voltage readings. Some scopes work for this or you can get a data acquisition (DAQ) module (look at either National Instruments or Measurement Computing). You can also use a fuel gauge chip (like the DS2770 or the DS2751) if you want the mote to be able to measure its own power consumption. Jacob On 8/15/07, SANG Junjun < [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> > wrote: how to measure the power on a running node? On 8/16/07, Jacob Sorber < [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> > wrote: You might also want to look at PowerTOSSIM. I don't really know how well it works, since I usually just measure the power on a running node (more accurate and fewer assumptions). Still, if you must simulate, that might help. Jacob Sorber On 8/15/07, Graham Healy < [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> > wrote: What architecture would you like to know the power consumption for? Also, If it's AVR I have used this with success in the past http://compilers.cs.ucla.edu/avrora/ <http://compilers.cs.ucla.edu/avrora/> Only problem is that the power consumption is based off an average for the particular mode the Atmel128L is in. Yours, Graham Healy On 8/12/07, SANG Junjun < [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> > wrote: I also want to know how to measure the power of a real node Thanks. On 8/11/07, bou ahm < <mailto:[EMAIL PROTECTED]> [EMAIL PROTECTED] > wrote: HELLO, I am new to tinyos ,I work on the version Tinyos1.1.0 with the use of TOSSIM simulator and the nesc language , how to know the quantity of power consumed by the node sensor or the sensor networks. THANK YOU _____ Ne gardez plus qu'une seule adresse mail ! Copiez vos <http://www.trueswitch.com/yahoo-fr/> mails vers Yahoo! Mail _______________________________________________ Tinyos-help mailing list Tinyos-help@Millennium.Berkeley.EDU <mailto:Tinyos-help@Millennium.Berkeley.EDU> https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help <https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help> -- Best Regards, SANG JUNJUN _______________________________________________ Tinyos-help mailing list Tinyos-help@Millennium.Berkeley.EDU <mailto:Tinyos-help@Millennium.Berkeley.EDU> https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help <https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help> _______________________________________________ Tinyos-help mailing list Tinyos-help@Millennium.Berkeley.EDU <mailto:Tinyos-help@Millennium.Berkeley.EDU> https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help <https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help> -- Best Regards, SANG JUNJUN ******************************************************************************* Please consider the environment before printing this email. ******************************************************************************* This email and any files transmitted with it are intended solely for the use of the individual or entity to whom they are addressed and may not be divulged to any third party without the express permission of the originator. Any views expressed in this message are those of the individual sender, except where the sender specifically states them to be the views of Thales Research & Technology (UK) Limited. *******************************************************************************
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