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Toys Hardware

Linux Duracell CPU Load Monitor 327

Posted by timothy from the void-your-warranty dept.
Nixon8Pie writes "Know those little self-testing batteries? How would you like to monitor your computers load with them? Well, now ya can. 'These throwaway testers are quite clever: they use a layer of conductive ink that heats up when an electrical current runs through it, in combination with a layer of thermally-activated dye that turns transparent when heated up, revealing a third layer of colored ink underneath. Because the layers are printed with varying thickness from "0%" to "100%", parts of them become yellow before others, creating a bargraph effect that varies with the current applied, the battery's body itself sinking the heat produced by the conductive ink.' Pretty cool stuff."
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Linux Duracell CPU Load Monitor More

Linux Duracell CPU Load Monitor

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  • Text of Page (Score:4, Informative)

    by Anonymous Coward on Wednesday February 11, 2004 @05:03PM (#8252876)
    The amazing Linux Duracell CPU load monitor
    Turning an AA on-battery tester into a CPU load monitor for Linux

    You probably know those onboard testers found on Energizer and Duracell batteries : press the two white dots printed on the wrapper, and magically the battery's state appears on a yellow bar. No need for a separate battery tester, everything is included on the battery itself. While not very precise, it's good enough to know if a battery is brand new, so-so, or completely dead.

    These throwaway testers are quite clever : they use a layer of conductive ink that heats up when an electrical current runs through it, in combination with a layer of thermally-activated dye that turns transparent when heated up, revealing a third layer of colored ink underneath. Because the layers are printed with varying thickness from "0%" to "100%", parts of them become yellow before others, creating a bargraph effect that varies with the current applied, the battery's body itself sinking the heat produced by the conductive ink. Informative details about those testers can be found here :

    HowStuffWorks
    The Duracell Battery Tester
    AA Battery Tester

    Here are instructions to turn such a tester into a not-so-precise analog display to monitor the CPU load on a Linux system, controlled by a serial port.

    What you need
    # An AA Duracell battery with a tester. Energizer testers should work too, but I haven't tried. I got a pack of Duracell Ultra M3 batteries, product code LR6-MN1500.
    # 1 x 3V power cube
    # 1 x 2 KOhm resistor
    # 1 x 4.7 KOhm resistor
    # 1 x 10 KOhm resistor
    # 1 x 4N25 or CNY17 optocoupler
    # 1 x BC547A or 2N2222A transistor
    # 1 x TIP41C transistor
    # 2 x 1N4004 diode
    # 3 x ON/OFF switche
    # 1 x female DB9 connector
    # 1 x large-ish breadboard
    # 1 x clear plexiglas CD case
    # 100 x patience
    Instructions to make the display
    Cleanly unwrap the tester off the AA battery. Be careful not to pull on any one side too hard, or you'll warp it and it'll be that much harder to connect on the breadboard. Personally, I lift both corners, gently unroll it on 3/4 mm, then use a knife and my thumb to finish taking it off the battery with an even pull. Here's what it should look like, before trimming the warped bit of the packaging :

    Here's the really hard bit : making a somewhat reliable connection between the tester's conductive ink points and the rest of the circuitry. To do that, place the tester on the breadboard, near the upper edge, and mark out precisely the breadboard holes the wrapper's white dots fall on. Spend some time aligning the right white dot (on the "minus" side), as the patch of conductive ink there is very thin and right on the edge of the tester. The dot on the left ("plus") side is less problematic.

    To make the connectors, solder bits of "hairy" copper wire (like that found on common mains electrical cords) in the holes you marked, and leave the "hairs" sticking out where the tester will be installed. They'll help make a correct electrical contact with the tester's conductive ink. Cut out a piece of clear plexiglas from the CD case, tape one edge to the upper edge of the breadboard, and punch a small hole near the bottom edge. This makes a window to hold the tester and press it flat against the breadboad and the connector.

    Solder the circuit's components at the bottom of the breadboard, under the window (there should be about 3 cm worth of breadboard left there). Here's the circuit's schematic:

    Notice the 2 switches around the 1N4004 diodes : those diodes are there to reduce the voltage fed to the tester, but depending on the individual tester and the quality of the contacts with the conductive ink, you might need to overload the tester a bit to reach 100%, or make it more reactive. With the switches, you can short one or both diodes, adding 0.6V per shorted diode.

    Once the circuit is done, feed it 3V and close all the switches. Then carefully align the tester on

  • A pity... (Score:5, Interesting)

    by HTH NE1 ( 675604 ) on Wednesday February 11, 2004 @05:04PM (#8252881)
    A pity that Duracell seems to not be interested in putting these testers on their batteries or in their packaging anymore. Saw a whole rack expiring March 2010 with not a single tester.

    • Re:A pity... (Score:5, Interesting)

      by Anonymous Coward on Wednesday February 11, 2004 @05:08PM (#8252950)
      I think that Energizer is putting them on their E2 batteries only.. I noticed the same thing last time I was buying batteries.

    • Re:A pity... (Score:5, Insightful)

      by KUHurdler ( 584689 ) on Wednesday February 11, 2004 @05:39PM (#8253316) Homepage
      I think its a pity for them too. Theres no quicker way to drain a battery than to use one of those little testers. Those little things would have you buying more new batteries in no time. Duracell should know that too.

    • Probably because the public isn't entirely stupid (Score:5, Insightful)

      by SuperBanana ( 662181 ) on Wednesday February 11, 2004 @06:11PM (#8253696)
      A pity that Duracell seems to not be interested in putting these testers on their batteries or in their packaging anymore

      I'd guess it's because people weren't as stupid as the battery companies thought they were. Most people know full well the strip works by heating up, and that wastes the power of the battery.

      On top of that, it's redundant; most consumer devices have battery gauges, the gauge can't be used when it's in the device, and when it runs out- you usually either have spares, or a quick trip to the quik-mart fixes the problem. That means that something that cost money to put on the battery was now raising the cost on the shelf versus the competition, or eating into the profit margin.

      Not to mention, non-rechargeable batteries are useless to most product designers, because the devices are way too a)small and b)power hungry.

  • Ah-may-zing (Score:5, Funny)

    by clifgriffin ( 676199 ) on Wednesday February 11, 2004 @05:04PM (#8252886) Homepage
    So that's how they does it. I personally use my mouth. I'm sure I'll regret it someday.

  • No more for Duracell or others? (Score:3, Interesting)

    by 192939495969798999 ( 58312 ) <[info] [at] [devinmoore.com]> on Wednesday February 11, 2004 @05:05PM (#8252900) Homepage Journal
    I haven't seen a tester for months, on any kind of battery. I don't think they are being made anymore, does anyone else know otherwise? I thought a gauge like that would be great for cpu physical temperature as well.

  • Wow (Score:4, Funny)

    by Anonymous Coward on Wednesday February 11, 2004 @05:06PM (#8252926)
    They must be using the batteries to run the site. Slashdotted already.

  • Instantly slashdotted (Score:5, Funny)

    by Anonymous Coward on Wednesday February 11, 2004 @05:06PM (#8252932)
    less than 5 posts and the French webserver has already surrendered.

  • I hope he doesn't have one of those on the server (Score:5, Funny)

    by Peeet ( 730301 ) on Wednesday February 11, 2004 @05:07PM (#8252934)
    that's hosting that website, or this could be the first slashdotting to start a small fire.

    Are you happy now? Y'all have slashdotted a battery.
    • If it does, unshort the pins quickly or you'll fry the tester...

      Man, I hate when I forget to unshort my pins and I get majorly fried. It totally sucks...

  • Marketing Genius (Score:5, Interesting)

    by Speare ( 84249 ) on Wednesday February 11, 2004 @05:07PM (#8252935) Homepage Journal

    When those little battery testers first came out, I thought it was pure marketing genius. Not for the convenience, but for the self-depleting consumable. It ranks right up there with Caller ID.

    "Here's a battery which you can wear out, even before you put it in your flashlight! You don't have to worry about shelf-life or temperature anymore, just squeeze the ends and you have a dead battery. No muss, no fuss, just two minutes from package to trashcan."

    The Caller ID, in its original implementation, though... sheer brilliance. "Let's make them pay to see the information that's already sent to the the switchbox! And if they don't like that, make them pay to HIDE the information on the switchbox. But that doesn't really hide it, it just flags it, so make them pay to see the HIDDEN information, or make them pay to REALLY hide it. We can go on like this forever."

    • you're no genius (Score:5, Informative)

      by Anonymous Coward on Wednesday February 11, 2004 @05:18PM (#8253074)
      "Here's a battery which you can wear out, even before you put it in your flashlight! You don't have to worry about shelf-life or temperature anymore, just squeeze the ends and you have a dead battery. No muss, no fuss, just two minutes from package to trashcan."

      what are you talking about?

      You can't drain the whole battery with a voltage tester in two minutes. It would take half an hour if you just shorted it out to drain it.

      OBVIOUSLY, the tester is there to check to see if those batteries you threw in the drawer months ago are still good.

      DUH
  • Now we can all buy more bootleg $1.00 packs of batteries from vendors riding the subways to test our CPU loads!

  • How about a /. effect monitor? (Score:3, Insightful)

    by ackthpt ( 218170 ) * on Wednesday February 11, 2004 @05:07PM (#8252946) Homepage Journal
    It's neat, but rather than skin a battery, I wonder if those same things which were, and maybe still are, in the plastic packaging would be easier to work with

  • A Mirror (Score:5, Informative)

    by trp642 ( 551059 ) * on Wednesday February 11, 2004 @05:07PM (#8252947) Homepage
    ... to keep our French friend's bandwidth down...
    http://home.cfl.rr.com/fnords/duracell_cpumon/ [rr.com]
    I hope my ISP doesn't kill me... ;)

  • Comment removed (Score:5, Informative)

    by account_deleted ( 4530225 ) * on Wednesday February 11, 2004 @05:08PM (#8252948)
    Comment removed based on user account deletion
  • So you rig your webserver to put out an increasing electrical charge as hits go up, you then have a nice visual indicator of when you're being /.'ed, just like their French page.

  • When I was a kid (Score:5, Funny)

    by Anonymous Coward on Wednesday February 11, 2004 @05:08PM (#8252960)
    The only battery affordable meter we had was for 9 volt batteries. And it was your tongue! And we liked the small spark it gave you to tell you it was working!
  • they use a layer of conductive ink that heats up when an electrical current runs through it Now I know why I got first degree burns on the tips of my fingers from using the tester too long.

    • that reminds me of a funny story... (Score:5, Funny)

      by morcheeba ( 260908 ) * on Wednesday February 11, 2004 @05:19PM (#8253095) Journal
      one day I noticed the icemaker in our freezer made the sound it does before it drops the cubes into the bucket. So, I looked in to see if I could watch it work... then I noticed that an extra metal tube went under the ice cube mold. I thought, wow, that's kinda neat - they must circulate a little extra freon through there to make sure the cubes are super-cold*. So, I decided to touch it to see how cold it was. It turns out that it wasn't a cooler, but a heating element that was used to slightly melt the edge of the cubes to release them from the mold. And it was very hot.

      That's how I burned my finger in a freezer.

      (* I was thinking that didn't make too much sense because I knew icemakers were often add-on features, and replumbing the freon would be too complicated to do for an accessory)

  • The obvious puns (Score:5, Funny)

    by thewiz ( 24994 ) * on Wednesday February 11, 2004 @05:10PM (#8252974)
    "His design is utterly revolting!"
    "Shocking!"
    "If I add more power, can I overclock it?"
    "An electrifying hack!"
    "More power to him."

  • Useless on a quickly varying load. (Score:5, Insightful)

    by stephenisu ( 580105 ) on Wednesday February 11, 2004 @05:10PM (#8252977)
    I find this to be amusing and all, however pretty pointless. These strips take almost a full two seconds to register a full change. Spikes in usage (good to know sometimes) will be completely missed. Plus I am willing to bet you need to recalibrate it often if your room temp changes by more than a few degrees.

    I would have RTFA, however it seemed to be down at the moment.

    • Comment removed (Score:5, Funny)

      by account_deleted ( 4530225 ) on Wednesday February 11, 2004 @05:16PM (#8253049)
      Comment removed based on user account deletion
    • spikes in CPU usage generally don't matter when you are monitoring general CPU load. Spikes are expected, and they happen, and if the processor is mostly running at an acceptable load (like under 50%) they don't matter. If the spikes get frequent enough to have an effect on the temperature of the monitor, then they are probably something to be concerned about. You are correct in that it's good to know about them 'sometimes' but most of the time it isn't.

      The load avg. on unix machines filter out 'spikes'
    • True, download LCDproc, take 3 minutes to hook up a $3.00 16X2 lcd from ebay,eio.com,or all-electronics to your useless parallel port and monitor many more things easier and winth more "cool!" factor coming from people looking at your machine.

      • take 3 minutes to hook up a $3.00 16X2 lcd

        Damn, you beat me to it...

        Actually, I had an LED bar in mind, rather than an LCD (better visibility in the dark), but same idea - More precise, costs about the same as a 4-pack of batteries, instant response, and WAY less kludgy.

        Still, I have to admit, finding a use for the testers on a dead battery has a fairly high level of geeky coolness.

  • Or you can use software... (Score:3, Informative)

    by moquist ( 233465 ) on Wednesday February 11, 2004 @05:12PM (#8253003) Homepage
    such as Gkrellm [wt.net], which is available for Linux, FreeBSD, Mac OS X, Net BSD, OpenBSD, Solaris, and Windows... if you install gtk, gdk, glib, etc.

    But a cheap hardware solution *is* pretty cool.

    Now, if you could hook one of those Duracell indicators up to your date for the evening...
    • Anything's better than the guy who bought an LED display for his case, then kept the server on the top shelf of his closet...
    • Actually I was thinking a mix of the two. Take his project but remove the el-cheapo duracell battery tester and replace with a VU meter or something similiar. A schematic similar to this [westhost.com] would work, although either the voltage supplied would have to be upped or some resistors need to be changed on that schematic, either way it would work and actually look somewhat decent (and respond in realtime too!)

      Put it on top of your stereo or in your cabinet and be the uber-geek (mine's right next to [njit.edu] my PC so it m
      • An even simpler project could be done if parallel ports are available.

        Driver that converts the load to one of 8 value ranges, raises one pin on the port for the value range in play, lowers the rest. The port value is latched and used to drive an LED.

        Gideontech.com has a project for a hard-disc VU meter; with an analogue CPU-use signal, it could be adapted
  • Many of you complain about the missing tester on newer batteries - but be honest
    Who ever used these things ?
    I for one did't and I don't know anyone who did.
    Whats the point in measuring the power of throw-away batterys anyway ? On rechargeable batterys this would be useful but not on throw-aways....
    • It's useful for us non-engineers who don't have The Knack to know intuitively which battery needs replacing in the remote.
      • As one of those engineers...
        Reading your manual will reveal that you should replace ALL of them at the SAME time. An imbalanced load can (probably won't, but can) cause battery leakage, explosions (not likely, unless you have multiple lithium ion rechargables, and you sit on it for ten hours simultaneously shorting the whole circut, in which case you are a nutjob (for buying rechargable lithiums for a remote (unless it has an LCD screen) not for sitting on the remote (unless is does have an LCD screen).
    • When you are cussing and swearing at your kids new christmas toy that doesn't want to work, and you need to know if its the batteries or the toy, but you are at the grandparents and have no voltmeter, they come in handy for knowing if you need to go and buy new ones.

  • Old School ... (Score:5, Interesting)

    by SuperDuG ( 134989 ) <be@@@eclec...tk> on Wednesday February 11, 2004 @05:15PM (#8253035) Homepage Journal
    ... Back when I was a kid slashdot used to have all sorts of crack pot stories where if it involved a computer or linux in some way it was posted to slashdot ... thats the way it was and we liked it.

    This is exactly what brings me to the nostalgia of what I like to see on slashdot, a story about some guy who attached some wires to a battery tester and then made a LINUX program to pop out the correct varying voltage to display on the battery itself.

    This is cool, and you want to know why? Its innovative, sometimes we go so long and things start to get stagnant that it takes these wonderfully clever people to come up with a new innovative way to do something. Is it practical, well no, but that doesnt mean its not cool.

    I for one would like to see more things like this and an SCO category so I can start to delete those stories from the front page. I like the true hacker stories, its fun to see how people are innovative. Really was something pleasant to read.

    Good Show!!

    • For someone who has been here a long time, you don't seem to have mastered Slashdot. There IS a SCO category. It is just called "Caldera".
      So, go here [slashdot.org].
      Go down to "Exclude stories from the homepage", and under "Topics" check the box next to Caldera.
      Then go all the way down and click "Save".
      There. No more SCO stories for you.

  • Neat. But WHY? (Score:5, Insightful)

    by wowbagger ( 69688 ) on Wednesday February 11, 2004 @05:15PM (#8253043) Homepage Journal
    OK, this is neat, but WHY?

    This same circuit could be adapted to:

    Vary the brightness of a small light bulb.
    Vary the speed of a small motor.
    Drive an old-style swing needle meter.
    (Variant of above) Drive a tachometer.

    Heck, why not interface to a slot-car and have it go faster the higher your load average is?

    • Re:Neat. But WHY? (Score:2, Insightful)

      by Cyno01 ( 573917 )
      Actually that last one would be pretty cool, slotcar case mod and all... But yeah, they have swing needle [xoxide.com] and tach [xoxide.com] versions of this sort of thing.

    • You answered your own question.... (Score:4, Insightful)

      by gosand ( 234100 ) on Wednesday February 11, 2004 @05:44PM (#8253386)
      OK, this is neat, but WHY?

      This same circuit could be adapted to:

      Vary the brightness of a small light bulb.
      Vary the speed of a small motor.
      Drive an old-style swing needle meter.
      (Variant of above) Drive a tachometer.

      Heck, why not interface to a slot-car and have it go faster the higher your load average is?

      I am sure you can take his code and modify it to do just that if you like. (and that answers part of your WHY question). The other part is just "because". This is true hacking.

      I do like the idea of an analog gauge to show the CPU load.
    • > Heck, why not interface to a slot-car and have it go faster the higher your load average is?
      How? Cool idea! Maybe even on the drivers stations.
      Slot Cars in St. Louis, MO [mgpmrc.org]

  • System Monitor (Score:3, Insightful)

    by milgr ( 726027 ) on Wednesday February 11, 2004 @05:18PM (#8253068)
    For cpu load average, I run System Monitor. It displays a pretty bar graph in the panel at the stop of my screen.

    Cost for running system monitor: $0.0
    Time for setting it up: 00:00:30

    Cost for Duracell load monitor: $9.95
    Time for setting up: 04:21:23

  • Temperature-sensitive Leucodyes (Score:5, Interesting)

    by G4from128k ( 686170 ) on Wednesday February 11, 2004 @05:19PM (#8253083)
    The activiation temperature of battery testers [howstuffworks.com] is a pleasantly toasty 100-120 F.

  • Battery testers.. (Score:4, Interesting)

    by eples ( 239989 ) * on Wednesday February 11, 2004 @05:25PM (#8253156)
    You used to be able to purchase those strips for a buck, although they were much better than the lousy ones they stuck onto the batteries.

  • Another electronics idea (Score:5, Interesting)

    by bigberk ( 547360 ) <bigberk@users.pc9.org> on Wednesday February 11, 2004 @05:26PM (#8253174)

    Here's something I did to help visually monitor my CPU temperature (and it doesn't require any software). You could extend it to monitor the temperature of any part that tends to overheat.

    Grab yourself a basic comparator such as the LM339 [national.com] and a temperature sensor such as the LM135 [national.com]. Make a circuit that compares the temperature sensor's voltage to a pre-defined threshold, and lights the LED if the temperature rises too much. The 'Typical Application' section of each datasheet pretty much shows you exactly how to wire up the parts.

    You can put this circuit in your computer's case (run it off a spare +5 voltage connector) and use a spare LED you find, like the Turbo light ;)

  • ...would be measuring the battery life of my laptop. (Stupid APM kernel oopses.) Just think: using a battery tester to... test... a battery!
    • If you know the battery pinout, I could see connecting your preferred style of voltimeter across it. Ideally with a switch, so you don't drain it when you aren't resding the gauge.

      I note that some batteries (like the ones in my old Toshiba 486) had + and - clearly marked on the unit
  • It is now official - Netcraft has confirmed: Duracell is dying

    Yet another crippling bombshell hit the beleaguered Duracell community when
    recently IDC confirmed that Duracell accounts for less than a fraction of 1
    percent of all servers. Coming on the heels of the latest Netcraft
    survey which plainly states that Duracell has lost more market share, this
    news serves to reinforce what we've known all along. Duracell is collapsing
    in complete disarray, as fittingly exemplified by failing dead last in
    the recent Sys Admin comprehensive networking test.

    You don't need to be a Kreskin to predict Duracell's
    future. The hand writing is on the wall: Duracell faces a bleak future. In
    fact there won't be any future at all for Duracell because Duracell is dying.
    Things are looking very bad for Duracell. As many of us are already aware,
    Duracell continues to lose market share. Brown ink flows like a river of
    shit.

    Let's keep to the facts and look at the rumors.

    Cum laude Theo states that there are 7000 users of Duracell. How
    many users of Caldera are there? Let's see. The number of SuSe versus
    Caldera posts on Usenet is roughly in ratio of 5 to 1. Therefore there
    are about 7000/5 = 1400 Caldera users. Connectiva posts on Usenet are about
    half of the volume of Caldera posts. Therefore there are about 700 users
    of nig cum. A recent article put TurboLinux at about 80 percent of the Duracell
    market. Therefore there are (7000+1400+700)*4 = 36400 TurboLinux users.
    This is consistent with the number of TurboLinux Usenet posts.

    Due to the troubles of SCO, abysmal sales and so on, TurboLinux
    went out of business and was taken over by SCO who sell another
    troubled OS. Now SCO is also dead, its corpse turned over to yet
    another charnel house.

    All major surveys show that Duracell has steadily declined in market share.
    Duracell is very sick and its long term survival prospects are very dim. If
    Duracell is to survive at all it will be among OS hobbyist dabblers. Duracell
    continues to decay. Nothing short of a miracle could save it at this
    point in time. For all practical purposes, Duracell is dead.

    Fact: Duracell is dead

  • in case you can't get to their site anymore... (Score:3, Funny)

    by Anonymous Coward on Wednesday February 11, 2004 @06:01PM (#8253577)
    For those of you who noticed the site's not available, there's a little bar graph on their server.

    Here's a live feed:

    E |==============X| F

  • Get some thermochromic ink (Score:3, Funny)

    by ColaMan ( 37550 ) on Thursday February 12, 2004 @05:08AM (#8256402) Journal
    If I was a heatsink manufacturer, I'd .....

    1) Write on the side of your CPU heatsink the words "If you can see this , it's too hot!"

    2) Paint that side with black thermochromic ink that changes temperature at 60 degrees C.

    3) Profit!!!

    Or, as the temperature drops from the bottom to the top of the heatsink, you could put things like "cool..." "warm..." "warmer..." "Hot..." "FUCK!" up the side of the heatsink. One glance and you'd know. Handy for those clear cases ;-)

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