Re: Alternative power/recharging source?
[EMAIL PROTECTED] wrote: And the EC, the memory, various pull up/down resistors, and few other suspend voltage regulators. All these add up to a non-trivial amount. you are not nessasarily going to be powering the system memory In the current setup powering the memory is not optional during suspend it is placed into self-refresh. Jespin at Usenix last year. however I can't just cite my memory, so I went looking on the website and found that snippet of information. however, it almost doesn't matter which of us is right. the mere fact that we are having this disagreement indicates a need for better documentation of this sort of info. It may not matter to you but it matters quite a bit to me since its part of my job. :) I'm part of the OLPC hardware team. The accurate measurement and reporting of the XO power draw is our responsibility. So when I see numbers flying about that I know are inaccurate I've been trying to correct them and find the source so it can get corrected as well. Unfortunately, as you and John Gilmore are pointing out, OLPC has previously made verbal and published statements with wattage numbers prior to mass production hardware. These statements, while not false, are only really useful when you know the context under which they were measured or extrapolated. In many cases this context did not make it into the statement or publication. So on that note here's some measurements I took this weekend with the context of the measurement: Consider these authoritative as of 2008-2-24. Sleep (No WLAN Firmware, Lid closed) .25W Ebook (No WLAN Firmware, Mono display, No backlight) .71W Mesh(Lid closed, WLAN) 1.1W Suspend (WLAN, Color display, backlight dimmed by ohm) 1.9W Suspend (WLAN, Color display, backlight minimum)1.7W Idle(WLAN, Backlight full, CPU on, no load) 3.9W 4.9 Peak Camera (WLAN, Backlight full, CPU on, high load) 6.5W 8.7 Peak Notes: These were measured and processed via my battery power logging script and a python hack I wrote (So I could quit using openoffice). See http://wiki.laptop.org/go/XO_Power_Draw#XO_power_draw for the code and a lot of gory details. No WLAN Firmware != 'olpc-control-panel -s radio off' since it does nto appear to turn every thing off. With radio-off Ebook mode drew 1.3W -- Richard Smith [EMAIL PROTECTED] One Laptop Per Child ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Alternative power/recharging source?
There has long been a lot of confusion about power consumption. Many statements were made over the years about the *design goal* for power consumption. The XO did not actually hit that design goal -- but since suspend/resume was the last major feature to debug in the hardware, until it got to the mass production stage, it was hard to measure its final power consumption. For example, OLPC put out a press release on October 22, 2007, entitled OLPC XO is world's 'greenest' laptop computer, claiming that When idle, the XO laptop uses a single watt of electricity. http://wiki.laptop.org/go/Image:Green.doc Then it went on to suggest how many gazillion barrels of oil would be saved if every computer did this. Only problem is, it's claiming the design spec, not a measured value. I haven't seen the raw measurements on MP hardware, only the ones reported to the weekend olpc community news. But Chris Ball measured it two weeks ago, and a mass production XO in sleep was burning 2064 mW (2 Watts +). Another place that needs updating: http://wiki.laptop.org/go/Classmate_and_XO_Laptop . It says Typical Laptop Power Draw is 0.5W mesh mode; (1W ebook Mode (idle)); 2-4W typical; 4-6W power user (max). There are probably more low-power references in slide decks shown at various conferences. I'm sure that there are things that still can be done in software (and/or rolling in hardware improvements on the production line) to reduce this power draw without losing any functionality. It was *designed* to use only a watt in suspend, and only two watts averaged over a week. But it's not at 1W yet, and may never get there. John ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Alternative power/recharging source?
On Friday 22 of February 2008 22:08:45 Richard A. Smith wrote: Ed Montgomery wrote: hours...using gravity! :-) (Consider the XO using about 2 watts...) Where did you see that the XO uses only 2 Watts? Thats only when suspended. Suspended: 2W Running: 5-7W Charging the battery: 16W This should be in the wiki. I just built me a charger using an old LED flashlight with a crank that can output between 2 and around 10 watts, depending on how ridiculous one looks when operating it (you just have to laugh at people cranking away at 10W). While i've searched for power requirements on the wiki, all I've come across are the power requirements of charging the battery. While it's possible I haven't searched extensively enough, XO's power requirements deserve a bit more press, i think. Regards, -- Jure Koren, unix developer signature.asc Description: This is a digitally signed message part. ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Alternative power/recharging source?
Came across this rather amazing item the other day, and instantly thought this might be a very, very useful power/recharging mechanism for the XO... A lamp powered by gravity producing 40 watts over 4 hours...using gravity! :-) (Consider the XO using about 2 watts...) Not affected by weather/season/time of day (e.g. solar/wind) or behaviour (animal/cow) or location, etc. An unlimited power source available anywhere anytime! Could this mechanism (which apparently is more durable than the LEDs in the lamp!) be modified to power and/or recharge the XO batteries, etc.? A preliminary article about the gravity lamp can be found here (from Virginia Tech): http://www.vtnews.vt.edu/story.php?relyear=2008itemno=111 Looking for last minute shopping deals? Find them fast with Yahoo! Search. http://tools.search.yahoo.com/newsearch/category.php?category=shopping ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Alternative power/recharging source?
On Fri, 22 Feb 2008, Ed Montgomery wrote: Came across this rather amazing item the other day, and instantly thought this might be a very, very useful power/recharging mechanism for the XO... A lamp powered by gravity producing 40 watts over 4 hours...using gravity! :-) (Consider the XO using about 2 watts...) this isn't producing 40 watts of power, it's producing light roughly equivalent to a 40 watt light bulb. super high power LEDs are about 10x as efficiant, lower power LEDs are even more efficiant. so this is going to produce 4w, possibly as low as 2w Not affected by weather/season/time of day (e.g. solar/wind) or behaviour (animal/cow) or location, etc. An unlimited power source available anywhere anytime! Could this mechanism (which apparently is more durable than the LEDs in the lamp!) be modified to power and/or recharge the XO batteries, etc.? the durability of this mechanism is theoretical at this point. and while it avoids the problems you describe above it gains it's own set (lots of fine cut gears, the need for smooth surfaces for the weight to slide on, etc) I'm not saying that this isn't a useful concept, but it's not perfect A preliminary article about the gravity lamp can be found here (from Virginia Tech): http://www.vtnews.vt.edu/story.php?relyear=2008itemno=111 an additional possible problem is the patent that they are trying to get on the mechanism. David Lang ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Alternative power/recharging source?
Ed Montgomery wrote: hours...using gravity! :-) (Consider the XO using about 2 watts...) Where did you see that the XO uses only 2 Watts? Thats only when suspended. Suspended: 2W Running: 5-7W Charging the battery: 16W -- Richard Smith [EMAIL PROTECTED] One Laptop Per Child ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Alternative power/recharging source?
On Fri, 22 Feb 2008, Richard A. Smith wrote: Where did you see that the XO uses only 2 Watts? Thats only when suspended. Suspended: 2W Running: 5-7W Charging the battery: 16W Doesn't it only use 2W-ish when it's in monochrome, screen refresh-only mode? --g -- Greg DeKoenigsberg Community Development Manager Red Hat, Inc. :: 1-919-754-4255 To whomsoever much hath been given... ...from him much shall be asked ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Alternative power/recharging source?
Greg DeKoenigsberg wrote: On Fri, 22 Feb 2008, Richard A. Smith wrote: Where did you see that the XO uses only 2 Watts? Thats only when suspended. Suspended: 2W Running: 5-7W Charging the battery: 16W Doesn't it only use 2W-ish when it's in monochrome, screen refresh-only mode? That would be suspended. which is sort of a largeish category. There's backlight on/off, wlan on/off flavors of that that use various amounts of power. So I guess suspended really should be 1-2W. If anything kicks in the CPU then its about 3.5W. I've had a few people recently throw out this 2W number and I want to make user that its not published somewhere as the XO power draw cause its not that simple. -- Richard Smith [EMAIL PROTECTED] One Laptop Per Child ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Alternative power/recharging source?
[EMAIL PROTECTED] wrote: no, in that mode it's down around .2W-ish I think in color, screen only mode it's ~1w Again whats your source for this info? Because its news to me. -- Richard Smith [EMAIL PROTECTED] One Laptop Per Child ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Alternative power/recharging source?
On Fri, 22 Feb 2008, Richard A. Smith wrote: [EMAIL PROTECTED] wrote: no, in that mode it's down around .2W-ish I think in color, screen only mode it's ~1w Again whats your source for this info? Because its news to me. http://laptop.org/en/laptop/hardware/specs.shtml LCD power consumption: 0.1 Watt with backlight off; 0.2-1.0 Watt with backlight on; in full e-book mode the display unit is the only thing getting power (radio off, cpu fully suspended) David Lang ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Alternative power/recharging source?
[EMAIL PROTECTED] wrote: Again whats your source for this info? Because its news to me. http://laptop.org/en/laptop/hardware/specs.shtml LCD power consumption: 0.1 Watt with backlight off; 0.2-1.0 Watt with backlight on; David Lang You are misinterpreting that. That is the display _only_. Not the system power. in full e-book mode the display unit is the only thing getting power (radio off, cpu fully suspended) And the EC, the memory, various pull up/down resistors, and few other suspend voltage regulators. All these add up to a non-trivial amount. Claiming that the power draw of the display unit in e-book is the system of draw of the laptop is inaccurate. It will be close if you were to throw up a page and let it sit there and never touch it. But the moment you engage the cpu to flip a page you draw 5-7x more power. The average draw then depends on how may pages you flip. We do not yet have any metrics for what that will work out to be. -- Richard Smith [EMAIL PROTECTED] One Laptop Per Child ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Alternative power/recharging source?
On Fri, 22 Feb 2008, Greg DeKoenigsberg wrote: On Fri, 22 Feb 2008, Richard A. Smith wrote: Where did you see that the XO uses only 2 Watts? Thats only when suspended. Suspended: 2W Running: 5-7W Charging the battery: 16W Doesn't it only use 2W-ish when it's in monochrome, screen refresh-only mode? no, in that mode it's down around .2W-ish I think in color, screen only mode it's ~1w David Lang ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Alternative power/recharging source?
On 22.02.2008 23:41, Ben Goetter wrote: hours...using gravity! :-) (Consider the XO using about 2 watts...) There seems little danger of this mechanism being useful on Earth for the XO-1. A 30kg human child who can move her own mass a meter vertically (via a series of pulleys, or perhaps just climbing stairs with a buddy riding piggyback etc.) If the child has a mass of 30 kg, why should he/she carry anything else piggyback one meter upwards to gain 300 J of potential gravitational energy (assuming g=10 m/s^2)? The child already gets that potential enery if it climbs the stairs alone. can invoke only 300J of potential gravitational energy, or enough to let an XO sleep for two and a half minutes assuming a 100% efficient conversion from gravitational to electrical potential. Regards, Carl-Daniel -- http://www.hailfinger.org/ ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Alternative power/recharging source?
On Fri, 22 Feb 2008, Richard A. Smith wrote: [EMAIL PROTECTED] wrote: Again whats your source for this info? Because its news to me. http://laptop.org/en/laptop/hardware/specs.shtml LCD power consumption: 0.1 Watt with backlight off; 0.2-1.0 Watt with backlight on; David Lang You are misinterpreting that. That is the display _only_. Not the system power. in full e-book mode the display unit is the only thing getting power (radio off, cpu fully suspended) And the EC, the memory, various pull up/down resistors, and few other suspend voltage regulators. All these add up to a non-trivial amount. you are not nessasarily going to be powering the system memory Claiming that the power draw of the display unit in e-book is the system of draw of the laptop is inaccurate. It will be close if you were to throw up a page and let it sit there and never touch it. But the moment you engage the cpu to flip a page you draw 5-7x more power. The average draw then depends on how may pages you flip. We do not yet have any metrics for what that will work out to be. if you flip one page every 5 seconds (a pretty fast reader) and for 1 second the system eats 5x the power of the display you end up with 0.2w of power. the rest of my quote that you clipped said that in full e-book mode the power consumption was ~0.2w. however, the initial source of the data was a presentation by Mary Lou Jespin at Usenix last year. however I can't just cite my memory, so I went looking on the website and found that snippet of information. however, it almost doesn't matter which of us is right. the mere fact that we are having this disagreement indicates a need for better documentation of this sort of info. David Lang ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: Alternative power/recharging source?
On 22/02/08 17:12 -0800, [EMAIL PROTECTED] wrote: On Fri, 22 Feb 2008, Richard A. Smith wrote: [EMAIL PROTECTED] wrote: Again whats your source for this info? Because its news to me. http://laptop.org/en/laptop/hardware/specs.shtml LCD power consumption: 0.1 Watt with backlight off; 0.2-1.0 Watt with backlight on; David Lang You are misinterpreting that. That is the display _only_. Not the system power. in full e-book mode the display unit is the only thing getting power (radio off, cpu fully suspended) And the EC, the memory, various pull up/down resistors, and few other suspend voltage regulators. All these add up to a non-trivial amount. you are not nessasarily going to be powering the system memory Its very difficult to suspend to RAM when the RAM isn't there. We've tried. Jordan ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
