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Re: Wearable config (was: RE: Good HMDs)

Isn't there any way to clean up this power supply?  If I remember
correctly, someone addressed and solved this problem already.  I think
it was the mp3mobile, or failing that, the empeg guys probably have it
figured out..

Michael Hohensee

Timothy Gray wrote:
> 
> If you are doing automotive then get one for each. voltage you would like to
> have.
> I have never seen a motherboard that actually uses the -5 volts for memory,
> in fact most asus motherboards dont even connect that pin anymore.
> 
> Here's a big note: DO NOT try to use desktop hard-drives in a mobile
> environment. regular 3.5 inch hdd's are fragile and suck up power like a
> vaccuum cleaner.. use a laptop hdd. and the most you are going to get is
> around 30-40 watts of power conversion with limited power filtering  an
> automotive electrical system ranges from 8 volts to 17 volts with spikes to
> 48 volts and transient voltage spikes in the thousand volt ranges when heavy
> loads switch. a mobile computer power supply is not a simple thing to design
> for "long term" use that would give you the 300 watt supply that the desktop
> pc power supply will.
> 
> as for the jameco number 155723
>                                              - 25 Watt
>                                              - Input Voltage: 9-18VDC
>                                              - Output voltage: 5VDC,
> 12VDC, -12VDC
>                                              - Output current: 4000mA,
> 250mA, 250mA
>                                              - Ripple p-p: 60mV, 80mV, 80mV
>                                              - 8-pins
>                                              - Size: 2.9"L x 2.7"W x 0.9"H
>                                              - Weight: 0.5 lbs.
>                                              - Short circuit protection
>                                              - Voltage accuracy: +/-2%
>                                              - One-year warranty
>                                              - Overcurrent protection
>                                              - I/O isolation: 100M Ohm min
>                                              - ISO-9002 certified company
> 
> this will do a 386 or 486slc motherboard.... or anything that is PC-104
> do not try to install several of these in parallel... they will fry,smoke an
> d burn nicely.
> you have to use a diode matrix to keep them from back driving each other
> which will drop the 5 volt side below acceptable levels.
> 
> this DC - DC converter is really overkill for a wearable though... but it's
> dirt cheap at $59.00USD
> 
> -----Original Message-----
> From: Marcus Porter <>
> To: Timothy Gray <>
> Cc:  <>
> Date: Thursday, July 15, 1999 12:27 PM
> Subject: Re: Wearable config (was: RE: Good HMDs)
> 
> >>www.jameco.com
> >>go to the DC to DC converters...
> >>find one that does +12 volts to +5,+12,-12 volts
> >>simple as pie
> >Do you actually know if such a thing exists or are you just assuming? I
> >hope you do because, I would LOVE to find out the part number. I've been
> >looking for months such a thing for the pc I keep in my trunk and have
> >never found one that didn't cost more than the cost of low power mother
> >board (which would get around the power supply with four voltages problem).
> >I finally made do with an inverter, which seems kind of a waste.
> >
> >i.e.  Car makes alternating current which is translated into DC which is
> >translated back into AC by the inverter which is translated once again into
> >DC by the computer's power supply.  There has to be a bettter way.
> >
> >I havn't found a converter in Jameco's catalog that provides all four of
> >the needed voltages, but perhaps I've missed it.
> >
> >>From: Stephens, Brandon <>
> >>To: Brian Rudy <>; 
> >><>
> >>Date: Wednesday, July 14, 1999 7:50 PM
> >>Subject: RE: Wearable config (was: RE: Good HMDs)
> >>
> >>
> >>>What are you using for your power conversion?
> >>>
> >>> > Current working wearable (WEll it kinda is... it's getting
> >>>mothballed soon
> >>> > for pc104 setup)
> >>> >
> >>> > 386 mini-baby AT motherboard...
> >>> > ide,svga,sound,network card ... all 2.5 inches tall, with brackets
> >>>removed
> >>> > (I found there are lots of cards only 2.5 inches tall)
> >>> > power converters for 5,12 and -12 volts.
> >>>
> >>>
> >>>
> >>>--
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> >>>
> >>
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> >
> >Marcus Porter, Webmaster at
> >http://www.iisworld.com
> 
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-- 
Michael Hohensee

"Remember, it takes 42 muscles to frown and only 4 to pull the trigger
of a decent sniper rifle."

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