At 04:03 AM 7/17/04 +0200, Thomas Shaddack wrote:
On Fri, 16 Jul 2004, Major Variola (ret) wrote:
Sorry so late ---but your can-shaped capacitors might not handle the rapid depressurization so well.
Perhaps it's time to challenge the introductory assumption. Why a laptop? There are many various embedded computers available on the market, eg. the one from <http://www.gumstix.com/>.
Um, even the small form factor PC on a board the size of your palm may still rely on caps in the power supply that don't handle 760 to 0 mm Hg/min so readily. Otherwise, there are many small PCs on a card if you look into the embedded marketplace. Complete with solid state disks, etc. COTS. Power dissipation is not a problem if you use a CPU like Via's and have a nice radiative heatsink. Or dick with Peltier-effect junctions at the expense of watts. ARM's edge is low power, but you may not want to run Linux or BSD or a RTOS, perhaps anon actually wants to run M$ in a low pressure environ. Perhaps that's why he's anonymous :-) My guess is regular ole airplane takeoff, but its not quite 0 torr at 35Kfeet, and I *think* the cargo part is pressurized, lest Fido suffocate. And while a SAM would be a great science fair project, you don't go above that limit. Perhaps anon will be a space tourist, wanting to take notes, on something heavier than a PDA+keyboard. I once TA'd at a UC, one advanced ugrad had a project for an atmospheric science prof building a board for the nose of a spyplane, to sample the air. (For ozone, not nucleotides. No, really.) He was interested in vibration problems; I told him to take his proto board on an offroad trip in his car to shake out the moths. Am not sure that epoxy cover makes a difference, the board manuf. go to lengths to avoid air pockets under traces, the ICs themselves fairly (albeit not guaranteed) encapsulated in an epoxy mix. We-all being scientists, I'd suggest looking up with the vacuum hobbyists do with fridge pumps, etc, and doing a bit of testing. I've even seen using a CRT as a vacuum source, break the glass neck and shazaam, a few litres of hard vacuum. -------- Got Kalman filtering?