Re: embedded aviation computers.

[Ole Barnkob Kaas <admin@tet.dk>]

Hello D.F.S., on 09-Feb-00, you wrote:

> First off, the group looks dead, what's up, or not up as the case may be?
> 
> 

2 days since the last post - the list have been more dead than that.

> In the never-ending quest....
> 
> All these projects related to custom hardware etc are very interesting, 
> but I really wonder if we'd not be a lot better off to grab semi-standard
> eqpt and get moving.

Sure, if you have such stuff lying around I suggest that you go ahead...

> 
> Decent linux code sould be portable to any reasonable platform as it 
> becomes reasonable in cost, reliability and support.
> 

Of course - theres no idea in making software that needs special hw to run.
Actually it should be that any hw that can boot a linux kernel should be able
to use the code - you might have to build your own drivers if you use very
special hw.

> More in that vein...
> 
> I'm looking at 2 options right now.
> 
> I already have, a 266 Mhz "Media GX" system board.
> 
> They were a generation of All-in-one mothgerboards that never
> quite took off.
> 
> It can take up to 256 Meg of ram and a has a 266 Mhz pentium clone CPU.
> I got it about a year ago for $39.00 including the CPU.
> It has everything on the motherboard.
> VGA, composite Video, Sound Card, Game port, parallel/serial ports and 
> a MIDI port. 
> I can think of several uses for everything but the Midi port.
> 

They might never took off because the original price *wasn't* $39.00 ;-)
Anyway thats good for you and it's probably the hw you wnat to use. I will
most likely use different hw - unless, of course, that I can get a similar
deal :-)

> I have power supplies designed for laptops that will take 14V DC and
> run the computer as well as charge a backup NI-CAD pack.
> I think these cost me $15.00.
> 
> I have 4 & 10 gig IDE disks kicking around just begging for a project.
> 

With those you can also record all radio communication...;-)

> This hardware would allow a DC powered computer that could be built 
> into a 8" X 12" X ~2" aluminum case for under $125.00 depending on 
> how much memory you load it up with.
> 
> Now the 2 options.
> Alltech electronics has 9" Grayscale backlit LCD displays for $89.00
> They INCLUDE a standard ISA controller that looks to the system like 
> a regular analog VGA controller.
> The displays themselves would need a case.
> They also have 8 push-button switches down each side of the display
> and 4 along the bottom. I'm thinking an interface based on those
> buttons would be very handy, many of the standard avionic displays
> do exactly that.
> 
> These are almost turnkey type systems relative to they type of 
> people I think we are on this list.
> 

People will probably select hw that balance betwenn their economic capability
and their skills to put it together. Again, the only requirement to the hw
should be that it is capable of running linux and you can provide drivers for
whatever devices you might want to utilize. 

> The second option is color TFT displays that would take more work.
> They are $99.00.
> They will take composite video input. The system board I listed 
> above will generate composite directly, there are converters out 
> there that take standard VGA inputs, and there is info on hacking
> these displays to run from VGA inputs with some additional circuits
> and funny display configuration. Very possible under X, a pain in 
> the butt under windows unless the card have special drivers that 
> allow it.
> But than again we are talking Linux here.
> 
> Either way I'm looking at about $200-250.00 for all the hardware
> for a kick-butt Flight management system using fairly standard
> and compatible PC make from common and cheap parts.
> 
> Comments?
> 

Hmm... aren't you missing something to compute - input from pressure
transducers, gps, etc. I like the LIAB because it already has pins where you
can connect various stuff. For an all-in-one computer you would probably need
some kind of adaptor card - maybe thats not that big a problem, but it all
adds up.

Btw what about gps antenna - I've seen that garmin makes one with RS-232
interface. Does anyone know of something better/cheaper. The big plus of the
garmin is that you just read the position - no need to mess with almanac and
translation of codes into coordinates.

Enough about hw - what about the sw. To start with, we need to store the data
collected (assuming that gps data is easily aquired from the serial port). On
"big" systems a mysql server could be used, but on systems with limited
resources something lesser would most likely be better. With that in place,
we already have a simple logger. Next, a user interface is needed - this
could range from a few buttons and a character display to TFT displays with
touch screen. The challenge is to build code that is easily adjusted to
whatever hw you use. 
Simply said it could be a core module where you plug modules for you hw into.
Each module (or driver) is made for one or more (similar) devices. Actually
something like selecting compile options for a kernel. After selction of
modules you can customise the setup and off you go.

Would python be usefull for such project?

          Regards/
                /Ole Kaas

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