The Well-Linuxed Car

[Roger Oberholtzer]

On Mon, 1 Dec 2003 05:31:34 -0800
Tony Alfrey <tonyalfrey at earthlink.net> wrote:

> And one other thing you might consider:  electronics put into cars, such 
> as switchmode power supply front-ends that "talk" to the car battery 
> are specified to handle very nasty overvoltages and voltage reversals 
> (which one might not normally expect from hooking stuff up to a simple 
> 12 V battery).  I'll look around to see if I can find you an 
> appropriate reference.  I'll look on the National Semiconductor site 
> 'cause they make lots of switchmode controller chips that must be 
> spec'd for this sort of environment.

Get a decent NON SWITCHING UPS. Then you run off the UPS' battery. It should
handle the power surges. If you spend money on any part in the car, this is
the place to do it.

The other big thing that can be a problem is grounding. The UPS MUST be
grounded to the vehicle chassis (along with the rest of the vehicle's
electrical system), as must all equipment. When choosing equipment, you will
save lots of headaches if you be sure to get stuff that can be grounded on
the power supply. Printers and TFT displays are often bad at this.We use a 1
inch wide multi-strand cable to ground equipment.

Even something as 'innocent' as an RS-232 port takes on new problems in a
vehicle if the equipment at both ends are not sharing the same ground sense.

If you get a display, look into VESA mounts. It is a type of mount on the
display that you can attach to some sturdy stand. We build our own stands
that the TFT VESA attaches to. Otherwise the display stand will break loose
after a short while. Attached is an example. The black part is metal and
made locally. It screws into the VESA display.


-- 
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? Roger Oberholtzer          ?   E-mail: roger at opq.se        ?
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