This is exactly what I'm currently working on ( http://wearables.blu.org/wear-hard-03/20039141.html ). The biggest issue I've encountered is powering the unit in a convenent fashion. Even though it's very light compared to most ATX (or even most other mini-ITX) systems, it's still a lot more power hungry than most of the wearable projects I've seen evidence of actual being made usable. A sample system, with an Eden processor, a laptop HD, and slimline CD will consume enough power, even while idle, that it will probably drain a 12v battery (10 1.2v C cells of 4000mAH or so) in a lot less that 5 hours, particularly if you're also powering a display. I haven't been able to find good power consumption figures on the Epia M, or the C3 processors (not Eden), but I suspect they would significantly increase power consumption. The only way I've found that would theoretically power a the system for about 6 hours (my goal), is using heavy SLA batteries (5-10 lbs to make it that long, depending on your system's requirements). These are also simpler to charge, because you can safely keep them topped off. I have yet to look into Li-Ion, but it might be a happy medium, with lower weight, and the ability to run a parallel circuit (lacking in NiCad & NiMH batteries). As was mentioned in a reply to my post, most 12v power supplies are expecting a constant 12v, no more or less, which could give mean your system cuts out before your batteries are fully discharged (since voltage drops as the charge diminishes), further diminishing battery run-time. You could work around this by using a system like the one described here http://wearables.blu.org/wear-hard-03/20039093.html , which integrates a charger, but you'd have to regulate the voltages yourself. I've already begun ordering some components to build my system, although I'm going to concentrate on getting it assembled and running off AC power, before I attempt any of my battery designs. Please keep me updated with your progress. I will continue to post mine to this list, assuming it's of interest to anyone here (the size & weight I'm working with make it more of a luggable than a wearable). -ben On Sunday 23 February 2003 14:23, Konstantin V. wrote: > Hi guys/gals. Im very interested in the wearable computing and for some > time I was interested in reading about it, because pc104 parts are kind of > costy and unavailable were I live (Mexico). > > I kind of interested in building a wearable for myself but it needs to be a > cheap solution or mid range. Interestingly enough EPIA's mothereboards and > particulary the Eden 5000 model looks kind of apealing for a wearable, with > footprint of 170x170 mm it is very small and its sells for a merely 100 > USD, Integrating 500 MHz Cyrix CPU VGA/TV-OUT/LAN/Sound/USB and more. I > think Linux runs well enough on this mobo but Im not totaly shure, the main > website is offline and I cant access it www.viavpsd.com , there is other > sites like http://www.viaarena.com which discusses Via's Mini-ITX > plataform. One link to Epia M series which is not the EPIA 5000 that I'm > talking about but you can apritiate the size of Mini-ITX format > http://www.viaarena.com/?PageID=187 I mean compare the functionality of > EPIA 5000 board to an existing PC104 or SBC board and then compare prices. > Im not into embedded and dont need a watchdog or data adquisition, just a > fun little system to carry around with PIM/Word processing/maybe video > capture(but that later) > > Now the TV-out NTSC/PAL is important because a cheap Head Mounted Display > could be a Kopin CyberDisplay320, a monocolor 320x240 display costing about > 60 USD wich could be driven by a Motorola chip part number MCVVQ111, the > documentation for the this display driver is explains how to build a > prototype board and this way integrating it into a very nice and cheap Head > Mounted Display. Here is a link to a MageForge article about a covert > CyberDisplay in sunglasses , courtecy of Mircea > https://securehost34.hrwebservices.net/~magefor/cgi-bin/view/Main/SunGlasse >s (The issue here is to get the MCVVQ111, I havent seen it on sale anywhere) > > I know it is low resolution and monocolor but I think it is a viabe > solution and it will be light and cheap, also low power consuming, and at > last but not least it is very very covertable. > > Thiking about power consuming, here is a mini power supply from > http://www.mini-box.com/pw-60.htm wich is a very small power supply unit > that fits directly in EPIA motherboard (u can download a video of the > mounting process wich is simple but ilustrative), the supply uses 12 DC > input and regulates the normal ATX psu outputs, proving 1 connector for a > HD + 1 connector for Floppy and a small 5 volts connector. > > Now if anyone would calculate the amount of power drained by this > motherboard + (put usual hardware that goes in the mobo like notebook HD + > Memstick ) + HMD + Input devices (Twiddler or mouse or maybe a PDA > keyboard) and evaluate how many battery packs (Li-Ion) would be needed to > power the whole system for a reasonable amount of time, dont know, maybe 5 > hours continuosly. Would it be 'wearable' ? > > What do you think about it? > > > > > --------------------------------- > Do you Yahoo!? > Yahoo! Tax Center - forms, calculators, tips, and more -- http: slightlymad.net smtp:AIM: bsarsgard ICQ: 42506676 (unreliable) -- Subscription/unsubscription/info requests: send e-mail with subject of "subscribe", "unsubscribe", or "info" to
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