Rugged tabletizing

Posted by: ANonEMouse

Rugged tabletizing - 11/22/06 09:38 PM

So, I'm thinking of building several (14+) 17" ruggedized MBP tablets.

Here are the requirements that I will have:

- Waterproof (3 feet submerged)
- Shockproof (10 foot drop onto concrete)
- Shockproof (Hardened Screen able to be jumped on by adult)
- Sunken quarter turn latch covers over ports and battery for easy access using a tool, but impossible access without, even with a pry bar.  The port covers themselves will need to be sunken as well as the latches.
- Functional Speakers
- Functional Camera
- Functional Wireless
- Functional touchscreen (not a problem)

Here are the thoughts that I've had.
- I'm planning on using stainless steel for the case itself, because of the strength.  I will then coat it in a hard rubber shell for some shock protection, and gripability.
- Waterproofing means sealing the case, so I will need to cool it without fans.
- I'm hoping to do this in 1.5 - 2" thick, 16" wide, 11" long.
- I would like to put two buttons on the side so as to externally access the zoom feature of Mac OS.  These buttons should not be able to be pried out. (maybe using the light sensors behind holes with plastic?)

I realize that most people may not have experience with this heavy of a mod, but I am looking for brainstorming regarding the heat dissipation and other issues that people may perceive.  Please also note that I am serious about this, and have a budget to do this in, so it is not a problem to replace units.  I will also have a professional fabricator do the steel work once I have my design in hand.

I cannot give any other details about the final use of them until after they have been built, then I will be happy to show pictures, and it will be apparent as to why I have my above requirements.
Posted by: Kisin

Re: Rugged tabletizing - 11/23/06 07:15 AM

Sounds expensive... liquid cooling is my first tought, but you still need to cool the water... same with oil inmersion... perhaps a twa stage process, using liquid cooling and some sort of cooling gas to cool the water.... im concerned abouyt usability though... stainless steel, complex cooling, hardened screen... it might be too heavy to be useful... good luck and keep us posted
Posted by: ANonEMouse

Re: Rugged tabletizing - 11/23/06 08:38 AM

Ruggedizing adds weight, there's no way around that.

If I figure that it will take two sheets of 16"x11"x1/8" Stainless (rough estimate, of course, as there is a hole for the screen, and the edges that will connect the two sides) the steel will weigh 5.8 lbs.  Now, figuring a 6.8 lbs Macbook - 2 lbs for the case, we are now at 10.2 lbs.  Figuring about 2-3 lbs for internal mods and the hardened glass, we are roughly the weight of two Macbooks, which I think is acceptable.

In my research, I've also just realized that carbon fiber may be a good material to use.  I will be talking to some CF manufacturers to determine if I can get steel like strength out of it at a thickness that would be usable in the computer.  If so, I may look into it further.
Posted by: manhackman

Re: Rugged tabletizing - 11/23/06 10:53 AM

polycarbonate (lexan, etc.) may prove to be a better solution than hardened glass...
Posted by: Waragainstsleep

Re: Rugged tabletizing - 11/23/06 02:42 PM

Liquid cooling is really the only way to go if these are going to be waterproof. But you will need a heat sink which protrudes through the rubber layer. I suppose the simplest way to build what you want, would be to coat the whole thing in a waterproof layer of shock absorbing rubber, then run either heat pipes or water pipes through the case and the rubber, terminating on a large copper plate, ideally on the top of the screen. Maybe another one underneath. You'll need fins or something on the bottom one to allow air to circulate.
Posted by: ANonEMouse

Re: Rugged tabletizing - 11/24/06 08:14 PM

Here's my current thinking:

I've found a maker of water proof cooling fans. (Sunon 40mm x 40 mm x 20 mm)

I was originally thinking that I would use them to cool a liquid cooling radiator, but now I have a different thought:

If I build a copper heat sink "tunnel" through the middle of the case, I can seal it from the inside of the case itself, providing for airflow to cool the processor (and video I assume), but not allowing for a break in the water seal.

I'm thinking 5 of them pulling air out the top would allow for this.  Once I have the first 17", I will measure the airflow that Apple puts in it, then account for the possible failure of a fan by doubling it, as they can get blocked.
Posted by: Saillar

Re: Rugged tabletizing - 11/25/06 10:46 AM

Since money is not an object, Eliminate the Macbook cases and build larger cases out of Titanium ( light weight and strength) and use the cases as large heat sinks since it will be submerged in water and the case can conduct the heat away from the interior utilizing more and larger fans.  Since the cases will be waterproof, I would vacuum all air and find a gas that will not condense as the computer is brought up or down into a cooler ambient temperatures.

Eliminate the hard drive for as much flash memory as you can buy and fit into the enclosure.  Shock proof the logic board and optical drives with Teflon or nylon springs.

Of course the weakest link in this whole scenario are the waterproof gaskets in the cases and your need to have waterproof 1/4 turn thumb screws. Not to mention sealing up around the screen even if you use a poly-carbonate covering.  As for the functional touch screen being "not a problem", I disagree.  To rugadize the screen you will need to put something in front of it, polycarbonate, lexan or even safety glass and you loose the touch screen capabilites.  Unless you use some kind of Wacom device.  I have yet to see anyone match up a electromagnectic screen with a Mac except for Wacom in their Cintiq line. Of couse I would love to see a Mac Mod with a electromgnetic screen.

I think you would have better luck in posting to the Navy Seals, they probably have a an Underwater Windoze Tablet that they spent 10 million dollars to develop and could probably sell as surplus for a hundred bucks.
Posted by: Waragainstsleep

Re: Rugged tabletizing - 11/25/06 12:58 PM

OK, custom enclosures are going to help alot. Instead of messing about with fans and non-condensing gases, you could fill the enclosure with oil. Just immerse the components. Then you have better cooling, no need for fans or vents (you could use a small pump but there would be convection currents caused by the hotspots like the CPU and GPU), plus the oil would also give some good shock absorption properties.
I would make the lower half of the enclosure a seamless unit with rounded corners. No sharp edges or welds to spring leaks. Like the original bottom case without all the holes in it. A rubber seal around the top would allow you to simply bolt the top half on. Easy access for maintenance, easy waterproofing.
Titanium sounds a good bet, with rubber around it to help prevent big dents and aid in waterproofing. Can you work your secret touchscreen solution into a setup like that?
The biggest problem with doing things this way (as long as you can sort out the screen) is going to be the battery.
Posted by: ANonEMouse

Re: Rugged tabletizing - 11/25/06 09:33 PM

I'm not talking about waterproofing for underwater operation.  I'm talking about waterproofing for "oops, one of the tablets fell into the pool again"

I'm a bit leery about Titanium because I understand its strength is in its flexibility, which causes problems when talking about strength of the internals, which is not.

I've been thinking about the Aluminum in the MBP.  My 15" powerbook survived a 8 foot drop onto concrete with little more than some dents and a scratch on the screen.  If I planned on the same grade Aluminum, with about 3mm thickness (I think that the MBP is 1mm) I should be able to get a considerably stronger case without so much of the steel weight.

Also, after looking at the internals of the 17" MBP, I am thinking that I would be able to make the top out of a passive copper heat sink at the top of the unit, then utilize the existing cooling system to circulate the air internally.  Doing so, would effectively seal the electronics, but allow for heat transfer to the outer air.

I wonder what the smallest enclosed airspace Apple would want a MBP to be run in without it overheating.  Given that I am planning on making a metal enclosure that is 16"x11"x2", there is much more air in the unit to transfer the heat out of the heat sinks, and transfer it into the enclosure.
Posted by: ANonEMouse

Re: Rugged tabletizing - 11/25/06 11:07 PM

My touchscreen technology is not really secret.  I was planning on using a resistive screen from either trolltouch or KEYTEC.  My thought is that they are essentially waterproof to a few feet, as they are sealed to the surface of the glass.

I have included a picture to illustrate what I am currently thinking.  The central box (without the curved edges) is 17" wide (I increased the space to allow for holding it without touching the screen) 12" high, and 2" thick.  I have removed the back and top so as to allow internal viewing.  I have not included any of the electronics from the MBP yet, as I need to model them still. 

In looking at the internals, I am wondering where and if I could have some longer wires made.  Specifically, the flex cable that attaches the IO board, as I would really like to place all of the ports on one side.  The non-orange wires will be relatively easy to replace.  I am also concerned that they may need to be a certain length because of timing issues.
Posted by: manhackman

Re: Rugged tabletizing - 11/26/06 10:29 AM

Originally Posted By: "ANonEMouse "

I wonder what the smallest enclosed airspace Apple would want a MBP to be run in without it overheating.  Given that I am planning on making a metal enclosure that is 16"x11"x2", there is much more air in the unit to transfer the heat out of the heat sinks, and transfer it into the enclosure.

I think it's more like how long until it overheats... maybe a mechanical fuction with valves and fans... the valves open, when temps reach a max, and vent all the air (one in, one out).  Combined with a moisture sensor that can override this from happening... and a "rain setting" that  gives you some warning beeps when its getting too hot.
Just brainstorming ideas....
Oh, another thing that you've probably already thought of is expansion and contraction issues.  I could forsee the computer running for a while and getting hot, and then being dropped into a pool of  cold water.  The seals may give due to the different rates of contraction, and all that work lost!
Posted by: ANonEMouse

Re: Rugged tabletizing - 11/26/06 02:51 PM

The valves and fans idea is an interesting thought.  I'm a bit leery, as what happens if the computer is dropped into the water while the valve is open?

I was planning on using liquid gasket to seal spaces that are not sealed in fabrication.  Considering that there is a wide variety of possible temperatures that occur in automobiles, I wasn't too concerned about expansion and contraction.
Posted by: Waragainstsleep

Re: Rugged tabletizing - 11/26/06 11:46 PM

Here's a thought worth sharing: If you attach the tablet to its user with a strong cable or chain, it will never hit the ground (or the water) even if its dropped!

NASA spent millions developing a ball-point pen to work in zero-G. The Russians used pencils.
Posted by: ANonEMouse

Re: Rugged tabletizing - 11/27/06 12:00 PM

Not true if the users will jump in the water.

Also, Russia had problems with graphite dust getting into everything, due to the lack of gravity to control it.
Posted by: manhackman

Re: Rugged tabletizing - 11/27/06 02:09 PM

may as well throw in a hi-def screen,
seems like there is only one sucessfully running; but quite a few folks tyring to work out the bugs!
Posted by: manhackman

Re: Rugged tabletizing - 11/27/06 02:17 PM

Oh, and heres the idea regarding the valves....
1)you get a warning indicating venting required
2)you press a button/ key combo to vent
3)valves close if you don't have the button/s held down
this could be done even if there was no warning. You may as well vent before a render ... A bit of a pain in the ass, but it's a small price for the most kick ass notebook ever!
I'd love to see a temp guage in the OS top bar, and be able to watch it decrease when you vent!
Posted by: ANonEMouse

Re: Rugged tabletizing - 11/27/06 04:12 PM

I love the idea, sounds like it should be a computer technology on Firefly or Battlestar.  However, it won't work in my situation.  I really like it though.
Posted by: Tayklor

Re: Rugged tabletizing - 12/18/06 10:13 AM

Cool it with a fan that is hooked to a one-way valve, so the air will come out and the water will not come in. maybe put the air under pressure and then have it blasted out.

Will the computer work in a vacuum?
Posted by: rpster

Re: Rugged tabletizing - 02/12/07 02:57 AM

go ssd with the hard drive, ultimate in shock protection, and can be used in vacuums.

as for the cooling, take a cue from zalman with their silent pc case. make the case the heatsink. or at least part of it. i envision the cpus heatpiped to heatsink fins on the top of the case and a cage protecting them.

oh, and there isnt a 17" widescreen touch panel from keytec, only a 15.4" wide.