Buying a new brain

Since a few pounds here or there is not a huge issue on an ATV, and I
imagine you'll be recharging the system battery with the ATV's gas
engine, the options are wide open. How about a good laptop with a
low-power Centrino CPU. $1200 can buy a very nice laptop, with its own
Li-Ion battery. I'd opt for a business model as they are more likely to
have legacy ports. An advantage of a laptop is that it will have an LCD
screen, allowing you to display system diagnostics and other
information, without resorting to little LCD panels.

A low-power CPU is useful for those times when ther ATV's engine is not
running. The typical laptop can be powered for several hours, even
longer if you turn off the LCD...which you'd do unless you're using it.

Finally, you'll want to consider the g-rating of the hard drive in the
laptop. I know you're already familiar with the issues, and the choices
for different boot options.

-- Gordon

"Gordon McComb"

I was more inclined to use a desktop, since I have one or two pci boards
that need to be connected.


I believe that's why Stanforn and Carnegie-Mellon both used Pentium M's in
the Grand Challenge.


For Koli (the small rover), I'm using solid state memory, but that
complicates the overall design a bit. For Yaboo (the ATV based), I will
either use the new Seagate for automotive applications or a regular HD
mounted on some sort of foam to isolate from shocks.

I believe I will have "Chips and Memory" (a local PC store) to assembly a PC
for me, and right now I'm trying to decide between a Intel Pentium D 930
Dual core and a AMD Athlon64 X2 Dual Core. I'm not sure what they mean by 64
exactly. Is it bus width, memory address, what is 64 bits? Most importantly,
can I use Win32XP with them? Or if I do, then there's really no advantage on
using a 64bit CPU?

Cheers

Padu

There are some ITX and Mini-ITX MBs with Pentium M's stuck on them, but
for the Mini-ITX all I've ever seen are boards with at most one PCI
slot.

I'd think about those PCI boards, though. Lotta little connections that
get vibrated around while on the road. If the board is screwed down it
shouldn't come out, but still the PCI bus is not made for mechanical
durability in the type of environment you're aiming for. Can you get the
same functionality via CardBus or better yet USB or Firewire 400/800?


64-bit internal architecture; i.e. deals with 64 bits at a time. I have
no direct experience with them, except that I've heard there can be
little compatibility issues with various software. Not sure it's worth
the hassle unless you have an app that requires it.

The Pentium D is not a low-power processor, though -- many times that of
a Pentium M. You'll be burning through batteries when the ATV's engine
is not running.

-- Gordon

Maybe you could be more specific about your requirements, namely,
electric power, size, weight, and computational power.  There's a big
difference between steering toward a gps waypoint and computing stereo
disparity at 60fps while updating a SLAM model.

For CPUs, I'd go with a Mini-ITX Pentium-M (btw, centrino is pure
marketing swill) if you're power constrained or an ATX single or dual
Athlon64 if you're not.  Max out the ram.  Mount the hard disk (ideally
mirrored, if only via ata raid) on a well engineered contraption
involving springs and foam rubber.

I would advise against notebooks.  You won't get the expandability you
need.  No PCI slots, few ports, etc.  The screen and keyboard may be
nice, but you're going to have to be able to do *everything* over a
radio link anyway, so really they're just a waste.  It will be more
difficult to give the hard disk the protection it needs.  The battery
isn't really useful because you are going to have main battery packs
large enough to run the computer anyway, and you'd probably prefer
having a relatively constant load on those rather than a huge spike
when the laptop decides to charge it's own batteries.

As another random thought, how about the guts out of a new mac mini?
That's a dual core pentium m in a pretty small form factor.

chris

The platform is capable of carrying a desktop weight without any problems.
The ATV has its own 12V battery, but I'll be using two additional 12V Optima
Deep Cycle batteries to power all the electronics (DC servomotors included).
Ideally we would need a Cray to implement all sorts of computations, but we
are restricted by the budget and weight. As I mentioned, this system will be
responsible for coordinating all different behaviors, estimating position
from sensor inputs and doing vision processing. What kind? Whatever we can
with the computer we get. For our smaller rover, based on a Via mini-itx,
the only vision stuff we can do is some basic obstacle avoidance and object
following. We hope to do more than that with the new system.


I know, lot's of foam. So, here's my question again... Why Athlon64 and not
a Pentium dual core? I'll use windows xp pro, is there any advantage running
winxp on a 64bit cpu?


That's the main thing. We already have two pci boards to be mounted.

It's not just lots of foam, it's frequency tuned vibration isolation as
well as proper dust protection/air filtering, g-shock protection,
thermal cooling, moisture protection, RF protection, etc.  Most PC
motherboards and their associated peripherals are not made to the
necessary mil standards for that type of environment.  Therefore you'll
need to go way over the top if you want decent reliability with off the
shelf PC hardware.  That may mean bigger, heavier, and bulkier than you
want.  I'd be willing to bet this is what caused some of the DARPA
challenge hardware failures.

Shawn

I got a decent MiniITX with 512mb off of eBay a few months ago for about $125.00
It has one PCI slot. Then you'll need a PSU unless
you want to risk plugging it straight into the power supply electrical system. I
got one that is made for a car PC ( that is
becoming popular these days ) because it handles all the 3vdc and 5vdc
connections needed for the motherboard straight from a
12-18vdc input.

Or maybe a ruggedized notebook like a Panasonic ToughBook ? There might be some
PCMPCIA cards, USB devices, or Firewire or Parallel
port gizmos out that there would let you connect your PCI stuff to the notebook.
Google on "Data Acquisition" + the appropriate
interface mentioned above and you might find something of use.

Could you switch out your PCI cards for something else, if you could get the
appropriate interface ?

Hope that helps. If I find anything more I will post it here.
Good luck !
JCD

I you really want rugged, something like this would be a good choice.

http://www.kontron.com/mobile/kmcpdproductdetail.cfm?keyProduct1425

I'm guessing this would break the bank though.

Shawn

It has one PCI and one mini PCI slot.

http://www.kontron.com/mobile/kmcpdproductdetail.cfm?keyProduct@767

Shawn