Re: [maemo-developers] Measuring power consumption of 770
On Tue, 2006-03-14 at 21:42 +0100, ext Claudio Scordino wrote: Does anybody have an idea about how to make the Nokia 770 work without the battery (just with the electric cable) or how to make such a measurement ? Why don't you just wire a battery to the battery pins and connect your meters to these wires? The voltage and the current provided by the battery is much different from the values provided by an electric cable connected to a socket (220V and 50Hz here in Italy). I know that, been there for 28 years :-D That's why our measurement tools wouldn't work with such a small current... Then I would recommend you to fix the design of you measurement setup if you want to get anything useful out of it. You know the battery capacitance, the promised standby time and browsing time, you can figure out the current value that you are going to measure. Many thanks, Claudio Cheers, Igor -- Igor Stoppa, Nokia M / Tampere Finland ___ maemo-developers mailing list maemo-developers@maemo.org https://maemo.org/mailman/listinfo/maemo-developers
Re: [maemo-developers] Measuring power consumption of 770
On Tuesday, 14. March 2006 22:42, Claudio Scordino wrote: Why don't you just wire a battery to the battery pins and connect your meters to these wires? I'd investigate this approach, maybe even building a battery emulator - a good quality 3.7 V regulated voltage source, if this is enough to fool the charging circuit. The voltage and the current provided by the battery is much different from the values provided by an electric cable connected to a socket (220V and 50Hz here in Italy). That's why our measurement tools wouldn't work with such a small current... Without knowing your tools let's screen the problem - the battery is 1500 mAh and it can deliver power to the device for hours, say 5 h. This means the average current draw during normal operation would be around 300 mA, most of which goes to the screen backlight and radios, I guess. If and when your algorithm can save some power, the difference in current would be very small and rapidly changing anyway. To make an exact measurement, you would probably need very good measurement equipment and also you would want a data logger with reasonably fast A/D converter to see and record what really goes on during the execution. -Teemu Many thanks, Claudio ___ maemo-developers mailing list maemo-developers@maemo.org https://maemo.org/mailman/listinfo/maemo-developers ___ maemo-developers mailing list maemo-developers@maemo.org https://maemo.org/mailman/listinfo/maemo-developers
Re: [maemo-developers] Measuring power consumption of 770
On Wednesday 15 March 2006 10:59, Teemu Nikkilä wrote: On Tuesday, 14. March 2006 22:42, Claudio Scordino wrote: Why don't you just wire a battery to the battery pins and connect your meters to these wires? I'd investigate this approach, maybe even building a battery emulator - a good quality 3.7 V regulated voltage source, if this is enough to fool the charging circuit. Following on from this, the best way to measure these currents and their change would be to put a precision(1% tolerance or better) 1ohm resistor in series with the supply and measure the volts across the resistor. This is typically more accurate than using the current scale on a dvm and as noted below is a better way if you are going to use a scope or a2d to monitor the current. The volt drop across the resistor would be V=I*R, so in the case of 300mA would be 300mV and therefore you might want to increase the supply voltage to take account of this. The power used in the resistor would be I^2*R which in this case would be 0.09 watts so a 1/4 (0.25)watt resistor should be fine. Caution: it was a long time ago:( that I leaned Ohm's Law and its derivatives, so caveat emptor The voltage and the current provided by the battery is much different from the values provided by an electric cable connected to a socket (220V and 50Hz here in Italy). That's why our measurement tools wouldn't work with such a small current... Without knowing your tools let's screen the problem - the battery is 1500 mAh and it can deliver power to the device for hours, say 5 h. This means the average current draw during normal operation would be around 300 mA, most of which goes to the screen backlight and radios, I guess. If and when your algorithm can save some power, the difference in current would be very small and rapidly changing anyway. To make an exact measurement, you would probably need very good measurement equipment and also you would want a data logger with reasonably fast A/D converter to see and record what really goes on during the execution. -Teemu Many thanks, Claudio ___ maemo-developers mailing list maemo-developers@maemo.org https://maemo.org/mailman/listinfo/maemo-developers ___ maemo-developers mailing list maemo-developers@maemo.org https://maemo.org/mailman/listinfo/maemo-developers -- V +44 (0) 1296 747667 F +44 (0) 1296 747557 C +44 (0) 7860 406093 Diamond Consulting Services Ltd Dinton Aylesbury Bucks, HP17 8UG England ___ maemo-developers mailing list maemo-developers@maemo.org https://maemo.org/mailman/listinfo/maemo-developers
Re: [maemo-developers] Measuring power consumption of 770
On Wednesday, 15. March 2006 13:44, Igor Stoppa wrote: If I'm proposing the battery, there's a reason ... Yes, this must be the least problematic way. and no, i won't go any further, but anyway faking a battery is not the scope of this study, according to my understanding, so using a real one will be just ok. You just need to measure and record the cell voltage too to get the actual power consumption. Anyway, IMHO, any power saving study should be done only after gathering info on the processor itself and the power management software actually in use. Definitely, unless they want to exercise with measurement technology... -Teemu ___ maemo-developers mailing list maemo-developers@maemo.org https://maemo.org/mailman/listinfo/maemo-developers
[maemo-developers] Measuring power consumption of 770
Hi all. We have a Nokia 770, and we want to study the effectiveness of some algorithms that reduce the number of transferred data in order to reduce the overall energy consumption of the device. To make this study, we need a way to measure the energy consumption of the device or, at least, an accurate measure of the battery charge. Our idea was to remove completely the battery, and measure the energy consumption through a cable connected to an electric socket with a multimeter. However, we noticed that the 770 does not work when the battery is not inserted, even if the device is connected to the electric plug with a cable. Does anybody have an idea about how to make the Nokia 770 work without the battery (just with the electric cable) or how to make such a measurement ? Many thanks. The best, Claudio Scordino _ Claudio Scordino Computer Science Department Ph.D. student University of Pisa, Italy Office: 341 Phone: +39 050 221 3137 e-mail: [EMAIL PROTECTED] home-page: http://www.di.unipi.it/~scordino/ _ ___ maemo-developers mailing list maemo-developers@maemo.org https://maemo.org/mailman/listinfo/maemo-developers
Re: [maemo-developers] Measuring power consumption of 770
Claudio Scordino wrote: Does anybody have an idea about how to make the Nokia 770 work without the battery (just with the electric cable) or how to make such a measurement ? When the battery is fully charged you can start measuring current in the cable since the battery is probably not used nor charged. Frantisek ___ maemo-developers mailing list maemo-developers@maemo.org https://maemo.org/mailman/listinfo/maemo-developers
Re: [maemo-developers] Measuring power consumption of 770
On Tue, 2006-03-14 at 14:53 +0100, ext Claudio Scordino wrote: Hi all. We have a Nokia 770, and we want to study the effectiveness of some algorithms that reduce the number of transferred data in order to reduce the overall energy consumption of the device. To make this study, we need a way to measure the energy consumption of the device or, at least, an accurate measure of the battery charge. Our idea was to remove completely the battery, and measure the energy consumption through a cable connected to an electric socket with a multimeter. However, we noticed that the 770 does not work when the battery is not inserted, even if the device is connected to the electric plug with a cable. Does anybody have an idea about how to make the Nokia 770 work without the battery (just with the electric cable) or how to make such a measurement ? :-O Why don't you just wire a battery to the battery pins and connect your meters to these wires? BTW, is there any pubblic reference to these algorithms? Many thanks. The best, Claudio Scordino _ Claudio Scordino Computer Science Department Ph.D. student University of Pisa, Italy Office: 341 Phone: +39 050 221 3137 e-mail: [EMAIL PROTECTED] home-page: http://www.di.unipi.it/~scordino/ _ ___ maemo-developers mailing list maemo-developers@maemo.org https://maemo.org/mailman/listinfo/maemo-developers -- Cheers, Igor Igor Stoppa (Nokia M - OSSO / Tampere) ___ maemo-developers mailing list maemo-developers@maemo.org https://maemo.org/mailman/listinfo/maemo-developers
Re: [maemo-developers] Measuring power consumption of 770
On Tuesday 14 March 2006 16:31, Frantisek Dufka wrote: Claudio Scordino wrote: Does anybody have an idea about how to make the Nokia 770 work without the battery (just with the electric cable) or how to make such a measurement ? When the battery is fully charged you can start measuring current in the cable since the battery is probably not used nor charged. It makes sense but I want to be definitely sure: I need an accurate measure, therefore I need something better than probably. Thanks, Claudio ___ maemo-developers mailing list maemo-developers@maemo.org https://maemo.org/mailman/listinfo/maemo-developers
Re: [maemo-developers] Measuring power consumption of 770
Claudio Scordino [EMAIL PROTECTED] writes: The voltage and the current provided by the battery is much different from the values provided by an electric cable connected to a socket (220V and 50Hz here in Italy). That's why our measurement tools wouldn't work with such a small current... Umm ... any cheap multimeter will do, for both voltages. And, just as a reminder, if you can't measure small currents: the smaller one will be found at the 230V side (given the same power consumption), and you'll much more likely run into problems about what you're really measuring there. Use the battery and measure there. - Heike ___ maemo-developers mailing list maemo-developers@maemo.org https://maemo.org/mailman/listinfo/maemo-developers
