Discussion- Multi-purpose Onboard Computers

RAM-Drive??

Colin, I've been thinking about that.. Somewhere I saw/saved a discussion from the Car-PC guys about setting WindowsXP up so it was not writing to Hard disk all the time..

I'm planning a 1 GB RAM, and a 512M RAM Drive should be workable. That should have no problem with the Data needed for several hours:
READ: Chart/Map data (including the automatic 'load next map' that OziExplorer does.
WRITE: Track (Log) NAV data, which is small, Log data from Onboard Systems like Engines / Power etc.

Then, once an hour or so, spin up the 2.5" hard drive and update files.

This would be more important in Sail Cruising, where you may be wanting to keep the total power to 25 watts or less.

I'll be doing some testing in 2 or 3 weeks of a system running XP and seeing what the average power is with all the power-saving options turned on.

Anyone have experience with these questions???

 

Booting and Running from other than HD, and why Linux is better

One of the reason I have been working on a system that works on both Windws and Linux, is the idea of booting computer from DVD-Rom and running swap files in memory and data storage on thumbdrives. Harddrives will not function well under rough water condition. Also this consumes less power. The down side is your favorite video game or radar may not work under Linux. So a hybrid system where main computer/server is linux and other computers is way to go. Let's face it a lot of computing on boat/ship is pretty boring. Nmea interfaces, and parts inventory can all be run in linux. So can gauges, temp monitoring, alarms. 95% can be run on linux and when you compare cpu and power requirement and reliability Linux wins hands down. 4 or 8 gb hold alot of data. And thumbdrives can be updated, removed, backup alot easier than hard drives.

All Windows are a hogs. You cant run it without alot of ram, and hard drive space.

 

Gauges

 

Truth about computers on boats

The Marine environment is hard on computers.
I had a computer on a stationary boat in a marina. The Boat never left the marina. In three years - I basically replaced computer 3 times.
Power supplies, got fried. Corrosion would affect board connectors. I had take boards out and clean slots and reinstall boards. Sometimes corrosion was so bad on board I had replace board. Computers also ran kind of hot, remember boat wasn't air condition most of the time. Hard drives failed more often.
Cpu fan would seized and finally one day it broke and when I open system the chips had corrode off of motherboard.

So conclusion.
Make computer Air tight. Liquid cool with heat exchanger.
Get power supply or ups that can handle marina/boat surges
Have as simple a computer as possible, the less boards the better.
Have redundancy and backups for everything, perhaps 3 like Space Shuttle
Then mount the whole thing in center of ship, away from windows, splash, moisture.
Be careful with cabling remember things like monitors, mice and keyboard cables where not design to be run thru bilge.
And make sure computer is cheap and easily replaceable when it breaks.

On a separate note, many years ago, I used to repair X-ray machines. There is an oil that you fill power heads with. It is a Non-hydroscopic? oil, this oil will not conduct electricity, at any level. No air or oil is allowed in chamber becuase they will spark. Inside x-ray we are talking many 100k volts. This oil in non-conductive. If you make a case and mount computer inside put Hard drive in a foam/gel bag and fill it with this stuff and cooled it-Your computer would be immune to the effects of the Sea. It would be safe in its mothers womb. It will work if someone is serious about making it. I thought about it. But I decide to go with cheaper computers that get replaced every year.

Remember if it is open to salt air, dont expect it to last forever.

 

Thoughts..

mydauphin, thanks for the good thoughts and opinions..

Right now I'm hoping that the combination of small low-power system boards and notebook drives will make the cooling (say 12-20 watts inside the system box) workable in a sealed box without liquid cooling. With some available corrosion-protection vapor stuff inside the box, I hope it will be workable for a long time.

On Gauges, Software etc: Tony, did you get any gauges programmed in RealBasic?? I have the magazine articles and I'm just starting to look at it. It would be nice to do gauges display in a lighter software environment. Linux is also supported at a little more cost, in RealBasic. Hmmm...

All this stuff needs to be thought out, prototyped, and then run on the Salt for a while before it will be credible as a "Good Idea"...

Right now all I have is Paper and parts still on the shelf. But I've been at the paper-only Fantasy point many times and had working systems come out of it, so I think we'll come up with some working solutions...

 

Would it be possible to build an enclosure that the computer sits in that scrubs the air? Does any one know of filters that would remove airborne salt? I know this would consume energy, but in some yachts, that isn't as big of an issue.

One of my computers in my studio is water cooled, but there are other components that need cooled within the computer that cannot be attached to the water cooling system. I think providing chilled air may be more reliable over all; not only for cooling, but more so for removing humidity.

 

About writing to a CF-card "too much": Both Sandisk and Samsung (and propably a lot of others) don't have that problem anymore. Both because the cards are much more "stable" nowadays (more write-cycles), but also because it writes to different sectors in order to "thin out the wear". Not to mention, it will simply write to another sector if a sector goes wrong. Try smashing a nail through the CF-card, it still works, only the "hole" doesn't work anymore (of course).

 

Terry, we all have common goals. Too bad we are all over world.

No matter the power consumption, no matter the little heat involved it has to go somewhere. You cant seal.

May be some kind of heat sink to outside of box, A heat sink is a function of material, mass and shape + Air circulation.

You cant really scrub salt from air at any great success. Only sealing works. There are many computer cooling systems in aftermarket that use liquid cooling. The cooling liquid doesnt have to go in and out of boat. It could be coolant to tank that acts as heat sink and pump could be very small.

Another idea that would work for a while is to seal motherboard with epoxy.
As long as temperature stays below 200 degrees it should not degrade too much. Just cpu fan, power supply and hard drive are exposed. Hard drives dont like heat at all. This is number one cause of failure, then shock.

Real Basics is good, at least as good as visual basic. The Windows version is $200, the Linux Standard edition is Free, but if you want to cross compile...The Professional Edition is $500. But sometimes they have half-price deals. It will run in mac. So if you use usb or TCP-IP based plc then your software can be multi-platform.

I have done this type of analog/digital automation before and it takes time to work out. The basics first is the core software design, which I have. I have been working on it for two years although only on occasions. The software will work with whatever hardware I want to go with.

USB, Serial or Tcp-ip are all equal from software point of view it is just a data stream. Also multiple copies of software run on different computers and talking to each other via tcp-ip can each be delegated to run specific house keeping functions.

 

Small World??

I think this is the right era for open-source collaborative design projects. It doesn't matter where we are as long as we can get some common hardware. I think any of the common PC hardware can be obtained almost anywhere.

Open-Seas people should take to this naturally!

I will be working more on NMEA instruments and Combiners (Multiplexers) based on Microcomputers, probably mostly PIC 24F and maybe some PSoc Touch Screen chips also. IF I get some small NMEA0183 boards working, THEN we'd have to figure a way to distribute them. BTW, Shenzhen, China is the lowest-cost place to get high-quality electronics built.. Hmmm..

I'm not sure where this will all go, but I hope we can keep figuring stuff out and getting to prototyping real things soon...

 

Heat Flow..

True! I think a reasonable amount of heat energy can go through a sealed aluminum box and be dissipated to cabin-environment air without too much temperature rise. With some simple corrosion-protective vapor inside that is rated for electronics, I think it can work.

What do the manufacturers of shipboard equipment on large boats do? They seem to use boxes with sealed cable entrances and doors with gaskets, from what I see. Can some of you with onboard experience with commercial electronics give us some examples of what is currently done and how well it works??

Attached is a PDF of one product described as "provid(ing) corrosion protection for metal components and parts enclosed in non-ventilated control boxes, cabinets or tool boxes up to 5 cubic feet (141.6 liters) in volume. The VpCI® (Vapor phase Corrosion Inhibitor) emits vapors that absorb as molecular layers on metal surfaces to protect critical, complex and expensive electronic equipment and other metal components during operation, shipping or storage." It is described as suitable for "Marine navigation and Communication electronic equipment." I emailed them about this application, including working disc drives and they said they have customers doing this successfully.

I'm hoping that something like this in a sealed box like an aluminum briefcase will allow reliable operation with no fans or liquid cooling. Only building this (which I hope to do soon) will tell the story.

 

Here is some info for VPc-105

The following document shows a test using a modified ASTM D 1748 test method:
http://www.cortecvci.com/Publications/Reports/02-137.html

ASTM D 1748 is a test method to evaluate standard rust-preventive properties of metal preservatives under conditions of high humidity. More info here:

http://engineers.ihs.com/document/abstract/NQEKCBAAAAAAAAAA

The test showed protection for a carbon steel panel sealed inside a one gallon jar to be greater than 34 days. The price is approximately $113.00 for 20 emitters.

 

Commercial equipment is designed with big heat sinks. But the units are sealed. That is way to go.

 

What are that paste called that created problems (because there weren't enough) in Macbook Pros? "Heat-sink paste"?

Couldn't one use that paste to create a connection between the CPU etc. to an aluminium case, and then have a passive cooler (ribs, basically) on the outside of that alu-case, making the case itself a giant heat-sink?

 

For the CPU and other heat intensive components, I would use a stand alone water cooler such as Koolance. My Koolance EXOS has three fans that blow through a radiator. It sits on top of the computer with hoses that run to the inside. This is an easy way to cool the inside of a sealed computer box. For a sealed box, you may have to place an internal radiator in the water loop with a fan blowing across.(to cool other components that generate heat that cant be attached to the water cooling loop) This isn't probably the most power efficient method, but it would allow you to enclose a high performance computer in a sealed case. Any peripherals(flash drives Cd/DVD drives) would have to be mounted separately outside the sealed case. They could still be behind a gasketed cabinet front.

 

Combining many ideas here...

That's what is looking like the solution.

mydauphine said "Commercial equipment is designed with big heat sinks. But the units are sealed. That is way to go." I have also seen sealed equipment in Semiconductor Factories I worked for, like that.

When I get my 12W system board and a 3W notebook hard drive in an aluminum case I will thermally connect the heatsink on the system board to the aluminum case. Then I'll do temperature measurements. 1 to 2 square feet (maybe . 2 Square M) of flat surface may be plenty. If not, then your idea of ribs on the outside is the answer.

Here's what the system board looks like (17 by 17 Cm)


I want to position this on resilient shock mounts at a level where the top of the aluminum 'briefcase' closes on it with a thermally-conductive pad (Used for power transistors etc) contacting the heatsink and pressing the system board lightly against its shockmounts.

I don't think 12-20 watts is going to be a problem.