Return to the archive index

RE: Finaly a cheap possible wearable solution?

I was thinking about this this morning and I was
think that I would have to build some sort of voltage
"regulator", but I am not expert on batteries. even with
the 12v power supply... (which I assume is expecting 12
volts dc input) I would have to regulate the power from
the bats. I can't remember the information from my basic
electrical course.

I am going to do the same thing as you.. I am going to
start puchasing my parts run the puppy off AC till I get
linux working. I will probably get it all together in a
project box of some sort then worry about DC power.

I will post my parts list after work tonight.

-----Original Message-----
From: ben [mailto:]
Sent: Monday, February 24, 2003 9:44 AM
To: ; Konstantin V.
Subject: Re: Finaly a cheap possible wearable solution?

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 
Wear-Hard Mailing List Archive (searchable): http://wearables.blu.org
Please, *PLEASE* don't subscribe through a forward/expander/false domain

---
Incoming mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.456 / Virus Database: 256 - Release Date: 2/18/2003

---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.456 / Virus Database: 256 - Release Date: 2/18/2003

--
Subscription/unsubscription/info requests: send e-mail with subject of
"subscribe", "unsubscribe", or "info" to 
Wear-Hard Mailing List Archive (searchable): http://wearables.blu.org
Please, *PLEASE* don't subscribe through a forward/expander/false domain

From Wear-Hard Mailing list Archive (WH)
Maintained by R. Paul McCarty

Archive created with babymail