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Rugged, Reliable, Low Power Linux Hardware?
Jesper asks: "OK, so I'm about to spend two years on a sailboat. The GUIs of all commercially available instrumentation electronics are ugly and outdated at best. But to develop my own I need a Linux based system that runs on 12V, uses very little power (preferably < 25W including monitor), has a sunlight readable waterproof SVGA display with min 16 colors and a waterproof input device (mouse, trackball or touchscreen. Keyboard not needed), and a rugged CPU with minimum footprint, preferably with a solid state harddrive. All this is perfectly possible to build, but I want to spend my energy developing the GUI, not building the hardware. I'm looking for tips on available H/W products."
For sailing you need, what, speed and heading? GPS gives both.
I was watching the America's Cup races, and those boats have a lot more sensors and displays than just that. They seem to integrate position, ground speed and direction (from the GPS), wind speed and direction (from an anemometer and wind vane) and water speed (from sensors in the hull) in order to give you the speed and direction of the winds and the currents in order to help you plot a more efficient course.
As you already mentioned, depth soundings would probably be in there as well. Ideally you'd probably also want to recieve broadcast weather charts and forecasts as well - not much point making good speed towards your destination if there is a white squall between you and it.
The next Cmdr Taco duplicate will be ready soon, but subscribers can beat the rush and see it early!
I've read that conformal coating can cause thermal problems if it wasn't taken into account when the circuit board was designed.
Mea navis aericumbens anguillis abundat
There are dozens of industrial laptops on the market that are waterproof (as much as anything with excited electrons is waterproof) and rugged. All of them will run on 12 volts. Power consumption would be less than 25 watts if you don't buy the latest and greatest model.
InitZero
to qualify...I used to develop aircraft cockpit displays and used linux and OpenGL for some of them...
Color LCD's have very little reflective properties so need a backlight. In addition, a color LCD has only a few percent transmissivity. To get enough brightness to see the display in sunlight (10000 ft candles), requires extraordinary brightness and power in the backlight. Some of the "sunlight readable" display put antireflective coatings and contrast enhancing filters in front of the LCD's. That works by making the display very dark so that the weak light coming through becomes a bit visible gainst the dark background. This doesn't work very well because the user's eyes have to switch between looking at the horizon with 90% reflectivity and the display with 5% reflectivity... very fatiguing to use the image is dark on deep black.
A backlit monochrome display will have about 25% transmissivity, but still not enough to make for a low power backlight.
You really want a reflective display...like the Palm Pilot's but they have limited viewabilty, require a backlight for twighlight and night operation.
Think about the ATM's you've seen in sunlight, do you like any of them? If good technology existed for this, people would use it.
For a rugged processor, we're using the RPX series from Embedded Planet. Runs on 5V, works over a wide temperature range (-60 to +100C in our tests) and supported by Hard Hat Linux from MontaVista (powerPC based). EP has a variation with a display.
Well, it all depends on what you need to connect. If you only need to connect one insturment the palm might do, Although the screen might be a little constricting. The company I work for makes some handheld, ruggedized, handheld PC class machines. These were ment mostly for a factory/warehouse environment, but might be suitable for you. In particular I might recommend our 6110 model. Which has a 1/4 VGA screen and a 486 processor. It comes with a MS OS installed, but some of the guys here in the software development area have gotten them to run Linux (Slack 6 I think). It has several serial ports avaliable, both internal and external, and 2 free PCMCIA slots.
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I'm sorry I can't be more help than I'm about to be, but here goes:
You will first need to decide what kind of reliability you really want. If I was going to be on a boat for 2 yrs, I'd spring for very reliable. Although it depends on how bad-off you'd be if it horked.
Search for Single Board Computer, and you should be able to find some that can withstand 25+ Gs and probably are waterproof to boot. Then make sure the OS and all essential functions run with no drive at all, from SRAM or FlashROM or something similar.
To me, I'd want something that would keep getting jolted around during a hurricane and still work. On the other hand, they use Thinkpads on the Shuttle *shrug*.
You can try to have it export to a drive ALSO, if you want, but I'd say only for recording and non-constant functions. 3 laptop drives might be cheaper than 1 solid state, and are probably as reliable, if swapping them is okay.
If you want some particular, but inexperienced, advice reply and I'll mail you.
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Palm Pilot + GPS = most of what you want. Get a waterproofing kit for your Palm at http://www.aquapac.net/homeframe.html. You can buy AAA size batteries anywhere in the world, or even recharge them quickly off of a solar cell charger.
3 rd.html) for your Palm as well. Bet you could write an interface to your depth gauge via the serial input.
Write a hack that keeps your Palm on all the time, and instead draw power directly from something other than AAA's, like one of those rugged marine-duty batteries.
For sailing you need, what, speed and heading? GPS gives both. Or buy a magnetic compass (http://www.precisionnavigation.com/palmnavigator