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Mac mini Sans Wires - Batteries Inside the Case

Posted by timothy on Wed May 18, 2005 08:53 AM
from the why-do-you-ask-why dept.
Hardware Hacking Debian Desktops (Apple) Power Hardware
An anonymous reader writes "Running Debian (or Linux generally) on a Mac mini is old news. Silas installed rechargable batteries inside the case, delivering a couple of hours of runtime while retaining the small form factor. Although it runs fine without wires, he had to plug in the monitor to be able to show that it was really up."
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  • iMac (Score:2, Interesting)

    by Mensa Babe (675349)
    Using an iMac would be a better idea, for it has a monitor already included.

    • Yes, but (Score:5, Insightful)

      by killa62 (828317) on Wednesday May 18 2005, @09:00AM (#12566051)
      the monitor would drain the batteries like hell

      • Re:Yes, but (Score:4, Insightful)

        by mbbac (568880) on Wednesday May 18 2005, @10:11AM (#12566798)
        What is the point in a headless computer that runs from batteries?

        • Re:Yes, but (Score:5, Interesting)

          by WD_40 (156877) on Wednesday May 18 2005, @10:26AM (#12566927) Homepage
          A small-footprint webserver with a built-in UPS.

        • Re:Yes, but (Score:5, Interesting)

          by danigiri (310827) on Wednesday May 18 2005, @11:13AM (#12567468)
          A lot.

          I am working on a research project that deals with Augmented Reality (basically VR goggles that are see through).

          AR deals with guys that hang around somewhere and use the following simultaneously to do some shit:

          - GPS receiver: to know where one is going and have data referenced following position

          - See-thru goggles that display geographical information (coming from an VGA port)

          - PDA or some sort of input/otput device

          - Wireless: for network stuff and group behaviour

          - Database: some sort of sane data repository that can be updated

          - Bluetooth: problably to connect all these devices together and not strangle the users with cabling

          Yeah, an small/light non-custom-built machine that can deal with all this easily would be great indeed. Oh, and sane developer tools as well.

          Once proof of concept and prototyping is done, someone else will find the funding for embedded custom development.
  • "Although it runs fine without wires, he had to plug in the monitor to be able to show that it was really up."

    Helps that Macs generally (yes, there are exceptions) run whisper quiet. Is the computer on? With a PC, just listen for the fan noise. With a Mac, hmm..can't tell, better look at the screen.

    • Wake up Neo. This is a dream. This is a big lie!

      If You think that 20dB from the PC case is a lot then maybe You should think it over.
    • Er... yeah, tell that to the wind tunnels I've had under my desk for the past couple years -- first an MDD, now a G5. Nice, yes, but quiet they ain't.

      PC's engineered to be quiet are quiet. My Dell is nearly silent. Macs engineered to be quiet are also quiet. It has nothing to do with the platform.
      • We have "silent" MPC computers in one of our computer labs. The silence is a copmromise between noise and melting the processor. Once in a while, we install a gaming image onto these machines... but it's pretty much useless because every single machine crashes solid after about ten minutes of gaming.

        Silent != good.
      • *sigh*

        I specifically wrote " generally (yes, there are exceptions)" to avoid this sort of response, by pre-acknowledging what you later wrote. I'm well aware of the wind tunnel Macs, but they are the exceptions. The iMac -- very quiet. Powerbooks -- silent. iBooks -- silent. Mac mini? I've heard silent too, and in fact that was the whole point of this thread. I was responding to an aspect of the mini in question from the article.

        • My Powerbook sounds like a jet engine is starting up on my lap when it gets too warm. Granted it's an older titanium model and I haven't used any of the new ones, but it's definitely not silent.
      • My Dell is nearly silent.

        I had to use a dell for a while, and it was unnerving. The lack of fan noise I mean.

        I felt a lot better once I got back to a computer I could hear.

    • Schrodinger's Mac (Score:5, Funny)

      by mathmatt (851301) on Wednesday May 18 2005, @10:19AM (#12566853) Homepage
      "Although it runs fine without wires, he had to plug in the monitor to be able to show that it was really up."

      Actually, the mac is both dead and alive until the monitor is plugged in - at which time the mac's probablility wave instantaneously settles in at its definite and final value...that is until the batteries run out, then it's a $500 doorstop.

  • External Batty pack + VCN (Score:3, Informative)

    by JawzX (3756) on Wednesday May 18 2005, @09:01AM (#12566062) Homepage Journal
    VNC is the obvious way to talk to the machine without a monitor connected...

    If an external battery could be housed in a mac mini form factor external case (stacked under/ontop of the mini) I bet battery life could be equivelent or longer than a power-book (no LCD to run). Could provide some interesting low-cost remote monitoring solutions...

      • Re:External Batty pack + VNC (Score:4, Interesting)

        by jamie (78724) <jamie@slashdot.org> on Wednesday May 18 2005, @09:16AM (#12566246) Homepage Journal
        Macs are sometimes a little too smart for VNC -- if they do not detect a monitor connected, they do not create a console display and the VNC server will fail because it does not have a display

        Old Macs, maybe. I had to plug in a display dongle to a Mac IIci server back around 1995. But the Mac mini doesn't need one. I have a mini in my basement, and it works fine over VNC with nothing plugged into its video port.

      • Try with Mac OS X 10.3 or later. If there are no display devices on-line the window server will create a virtual framebuffer.

        In Tiger, Mac OS X 10.4, fast user switching gets a related feature. When a user session is switched off-screen, if a screen watching program such as OSXvnc-server is running, the off-screen session will get a virtual framebuffer so that it can be remote-operated while another user session or a login window is on the hardware console.

        Try running OSXvnc.app, for example, and switch

  • Thats nothing (Score:5, Funny)

    by Timesprout (579035) on Wednesday May 18 2005, @09:07AM (#12566134)
    wait till you see my gerbil powered mini. I'm having a small problem with it though, it runs just fine in my test harness but the power seems to tail off and then die shortly after I hermetically seal the case.

  • 4Ah 20V battery and 1:50 runtime = 40W draw? (Score:4, Interesting)

    by Anonymous Coward on Wednesday May 18 2005, @09:07AM (#12566140)
    The author says he measured 14-20W for the mac mini under load, but his 80W-Hr battery only lasted 1H:50M, implying a 40W+ power draw.

    Am I missing something?

    • Re:4Ah 20V battery and 1:50 runtime = 40W draw? (Score:4, Interesting)

      by enosys (705759) on Wednesday May 18 2005, @10:31AM (#12567006) Homepage
      The author says he measured 14-20W for the mac mini under load, but his 80W-Hr battery only lasted 1H:50M, implying a 40W+ power draw.

      It's not that simple. It's not like the batteries supply 80W-Hr of power at their rated voltage and then shut down. With most types of batteries the voltage drops slowly as they discharge. Batteries also aren't perfect voltage sources. They have internal resistance, which means that if you draw more current the voltage will drop. I suspect the voltage got too low because of these two factors and the Mac Mini crashed or shut down. The batteries might still be able to power a flashlight.

    • Several things:

      The author likely measured average consumption sans peaks. In other words, the multimeter he used does not respond to short huge current demands. Depending on the meter, in fact, and the switching regulator inside the mini he may have a very bad reading. This kind of measurement is difficult to take accurately without equipment meant to measure this - one which integrates the current consumption over time, including peaks, for instance.

      The cells are rated for 4AH, but there's no guar

  • Huge new product line! (Score:5, Funny)

    by dave_mcmillen (250780) * on Wednesday May 18 2005, @09:08AM (#12566152)
    Hey, this could be the start of something big! What if he were to also install a portable screen? Maybe it could, I dunno, fold down into the top of the machine, or something. Then you could carry the computer around and do stuff with it, wherever you went, while resting it on your knee. A sort of "knee-top" compiter, though maybe there's a better name someone can think of . . .

  • Darwin award soon (Score:5, Informative)

    by ballpoint (192660) on Wednesday May 18 2005, @09:08AM (#12566162) Homepage
    Exactly how is the LiPo battery charged ?

    Without a proper charger, combining the energy density of a 80Wh battery with highly reactive Lithium is a recipe for disaster.

    http://www.rcgroups.com/forums/showthread.php?t=20 9187 [rcgroups.com]

      • Re:Darwin award soon (Score:4, Informative)

        by ballpoint (192660) on Wednesday May 18 2005, @09:49AM (#12566591) Homepage
        A simple power supply with a current limiting knob isn't safe. Overcharge a LiPo and you'll set it on fire in a rather spectacular and difficult to extinguish way.

        A charger that is specifically designed for LiPo charging is a MUST.

  • 12W (Score:5, Informative)

    by IceFox (18179) on Wednesday May 18 2005, @09:09AM (#12566168) Homepage
    Wow, at only 12W for the entire system? It is pretty hard to get a x86 box that low for that
    cheap.

    -Benjamin Meyer

  • Article Text (Score:5, Informative)

    by riffzifnab (449869) on Wednesday May 18 2005, @09:15AM (#12566236) Journal
    Mac Mini Surgery

    I had an itch to scratch so here it is...

    Earlier this week I read an article on the Debian Weekly News, about a Debian box running on 3 Watts, and it reminded me of a project that I was asked to put on the shelf some time ago. The gist of the article linked to by the DWN was that Alex Perry got to wondering how much power his Linksys switch was sucking down whilst running 24/7, and found that his Manga, an ARM based router box, not only consumed less power but was able to run full blown Debian to boot. His point was "If I am going to pay to have a switch run 24/7, I might as well have the switch be a useful server as well." Following his article the PepLink community promptly got X11 working on the Manga and Alex's website was updated with the screen shots, which I might add are quite amusing.

    While I do sympathize with the original thrust of the article, I must say that the Manga's ARM is a rather diminutive processor for a desktop machine these days. So my question is why would you run a Manga as a desktop to get down to the 3 Watt mark when for just a few more Watts you can run a box with a G4 processor? Yes, I am talking about that little machine that all of my geek friends (me included) seem to be drooling over as of late. The Mac Mini!

    Several months ago I was in need of finding a small but powerful computer that could be run for a long period of time on batteries and not be a burden to carry. I was looking at several embedded options from places like kontron and mini-box, when I saw an article on the Mac Mini. Looking at the limited specs for the Mac Mini on Apple's website I began to suspect that if I removed the cdrom drive I would be able to fit a "lithium-ion polymer" battery pack inside the vacated space. I say that I suspected this because Apple is lousy about posting specs about internals and stuff that your Grandparents wouldn't normally ask about. So I ran down to the local Apple store with my trusty calipers and had one of their technicians go into the back and measure the dimensions of the cdrom drive for me. The numbers that he gave me made my day, the batteries would fit! Now about power specs. Apple of course did not have the DC power specs online, and nobody I talked to at the Apple store or on the support line could get them for me. In an act of desperation I resorted to sending email to combinations of addresses like steve_at_apple.com sjobs_at_apple.com, steve.jobs_at_apple.com, etc asking for the specs. Funny enough I got a reply (No, not from Steve Jobs) from an Engineer who was quite helpful. It looked like the Mac could do it, so I decided to get one and hack on it. The Mac was dirt cheap compared to the embedded systems so it was a very limited risk approach to proceeding on the project.

    I ordered the Mac, a 4GB Hitachi Microdrive, and a laptop-IDE to CF adapter. I also talked to Mike (Dr. Zhang) at SKC PowerTech, Inc, and he was kind enough to send me some batteries for evaluation. The batteries were a new design and were not yet in production, so there was a bit of a lead time on those, but at the end of two days I had the rest of the necessities at hand. First things first, I measured the out of the box power draw of the Mac Mini, which turned out to be only 12 Watts! This was better than the specs I was given. I then proceeded to remove the hard disk and replace it with the Microdrive-CF adapter setup. Then I got me a Debian (Sarge) disk *GRIN*. This was the first time I had touched a Mac, and I was pleased to find that the Debian install on the Mac was smooth and painless. After getting the system up and running, I did some stress testing on it. The testing involved running simultaneous FFT routines (like 30 of them) on 80MB data files. The system was so heavily loaded that it took about 15 minutes to log into the machine from another terminal, and another 15 minutes to get to the bash prompt. During this utter thrashing of the system the highest the power usage spiked to was 20 Watts, but it stayed around 14
  • So, could they not just connect to the thing over a WLAN? I suppose, they couldn't verify that it was that specific mini...
  • He says that he used two wires for each power connection to ensure that it could carry enough current. Does this actually work? Doesn't electricity take the shortest path thus overloading the wire with the least resistance?
  • It looks like a nice hack... But what would be really cool, was if you somehow could get the power from the monitor.
  • buy a laptop....iBook....

    ???????

  • I'm holding out (Score:4, Funny)

    by WormholeFiend (674934) on Wednesday May 18 2005, @09:25AM (#12566332)
    for an Apple computer that runs on human blood [slashdot.org]!

    Oh wait...

  • Come on now....give the guy a break (Score:5, Insightful)

    by gadgetbox (872707) on Wednesday May 18 2005, @09:39AM (#12566490)
    Seriously, give the guy a break. This mod probably wasn't as easy as it looks. Yes, it does have a very limited practical application due to the fact that you need a powered monitor (network access aside), but....in the long run, things like this can serve up some very innovative creations. Perhaps someone else will see this, and take it a step further, and eventually some ingenious application for a battery powered Mac Mini will appear. I say bravo, good job, and keep on tinkering.

  • Server batteries (Score:3, Interesting)

    by scrotch (605605) on Wednesday May 18 2005, @10:08AM (#12566762)

    I've often wondered why there aren't servers with batteries built in for a few minutes of power after the UPS goes down.

    Apple could get especially good results from doing this because of their hardware-software integration. Imagine an xserve with ten minutes of battery power built in. Can't you see the interface where you have the computer run a script that emails you after it's been on battery power for two minutes? Imagine hooks for when battery power starts to be used, and when a clean, painless shutdown begins, or when power is restored before the battery runs out.

    This would be of great value to me anyway. I know some UPS software offers this (though I'm not sure what the state of Mac-compatibility is), but Apple could surely do a better, more thorough job.

    • Re:Server batteries (Score:4, Insightful)

      by drinkypoo (153816) <martin.espinoza@gmail.com> on Wednesday May 18 2005, @10:55AM (#12567271) Homepage Journal

      I've often wondered why there aren't servers with batteries built in for a few minutes of power after the UPS goes down.

      spend less time wondering and more time doing research. Some of IBM's AS/400 systems (whatever-series, now) have a built-in UPS; they are sold as a complete computing solution for businesses. Just plug it in, and compute.

      Or, you know, you could try a google search [fuckinggoogleit.com], if that's not too much trouble.

    • I havn't read the fucking article so I don't know if its possible, but the best use would be just using the battery as backup and having a fileserver that can last a few hours even in a power outage.

    • Re:And the use would be? (Score:5, Insightful)

      by Skynet (37427) on Wednesday May 18 2005, @09:00AM (#12566053) Homepage
      Since when did nerds need a reason to do something nerdy?

      This is Slashdot!

    • Re:And the use would be? (Score:5, Insightful)

      by hey! (33014) on Wednesday May 18 2005, @09:02AM (#12566077) Homepage Journal
      And the use would be?

      As a random act of senseless beauty.

      You see, geeks do have poetry in their souls. It's just in a language they don't teach in the English department.

      So -- do what appeals to you. The utility will come later.

    • Re:And the use would be? (Score:5, Funny)

      by FunWithHeadlines (644929) on Wednesday May 18 2005, @09:03AM (#12566102) Homepage
      "What exactly do you do with a Mac mini that you can't get any visual output from"

      Bah! Real programmers don't need screens. Why, in my day we didn't even need keyboards to issue our commands. We merely bellowed at the computer and it whimpered off to do what we wanted. Honestly, the kids these days...

      • When I saw this, it reminded me of a very old joke I saw once.. and compelled me to post it here.

        Top 12 Things A Klingon Programmer Would Say

        12. Specifications are for the weak and timid!

        11. This machine is a piece of GAGH! I need dual processors if I am to do battle with this code!

        10. You cannot really appreciate Dilbert unless you've read it in the original Klingon.

        9. Indentation?! -- I will show you how to indent when I indent your skull!

        8. What is this talk of 'release'? Klingons do not make software 'releases'. Our software 'escapes' leaving a bloody trail of designers and quality assurance people in its wake.

        7. Klingon function calls do not have 'parameters' -- they have 'arguments' -- and they ALWAYS WIN THEM.

        6. Debugging? Klingons do not debug. Our software does not coddle the weak.

        5. I have challenged the entire quality assurance team to a Bat-Leth contest. They will not concern us again.

        4. A TRUE Klingon Warrior does not comment his code!

        3. By filing this SCR you have challenged the honor of my family. Prepare to die!

        2. You question the worthiness of my code? I should kill you where you stand!

        1. Our users will know fear and cower before our software. Ship it! Ship it, and let them flee like the dogs they are!

        Seeing as how old school programmers think like klingon programmers, I believe that it can be reasonably assumed that all old programmers are klingon.

    • Re:And the use would be? (Score:5, Funny)

      by Cecil (37810) on Wednesday May 18 2005, @09:09AM (#12566169) Homepage
      It's a portable wireless hard drive for my laptop. Duh.
    • 2 hours isn't to bad. Think of it as an imbedded UPS. for your system.
      Preventing data loss on an accedental power outage.

      Secondly if this job is done right it could help improve the life of the computer, giving the system a reliable source of power helps keep the equiptment from those little surges and dips.

      Portability. 2 Hours should be enough to get you to your location without bringing the system down. So when you get to the office and quitly plug in the system to the projector bingo your keynote pres

    • Moving it to another room (Score:4, Interesting)

      by Space Coyote (413320) on Wednesday May 18 2005, @10:20AM (#12566864) Homepage
      One of the things I tend to use the battery in my laptop for most is to keep the thing on when I move from one room to the other in the house and then plug in again. Seems like a sensible thing someone would want to do with a mini, to go from a desk in a study over to the bedroom or to the stereo to play some music for a while without having to shut down and restart.

    • Re:sniff sniff (Score:3, Interesting)

      by hey! (33014)
      Not quite, cause you'd have to get it up there right before the packets you were interested in hit the network.

      However -- figure out some way to parasitically power it off the wiring going to the flourescent lights, in a way that can be installed in one or two minutes, then you'd really have something.

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