Hi Andy,
No... I havn't considered that, because I'm completely new to all this and the list of things I should have considered but havn't even heard of is possibly infinite.
Typical displays on a racing yacht are about 5" - 7", and apart from being tough and waterproof, highly visible, anti-glare etc. they do very little - often just display one number plus annotation (e.g. Boat Speed, Knots).
Luminance requirements appear to be around 1000 cd/m2.
I don't think performance will be an issue with the way I was thinking of doing it - bought some bits since my original post, but still happy to start agin if there is a better way - because all that is going up and down the I2C bus is the variable data which constitutes maybe 50 -100 different 3 digit integers updated 10 times a sec. The Arduino controlling each display would take the numbers it wanted from that lot (based on the display format it was currently displaying) and send the graphics commands to the screen controller.
Just to give you an idea, I have a .jpg of the first screen format I designed - and probably the most complex we'd have - but I can't figure out how to upload it to your site so I can refernence it within an
code. Anyway, it contains 6 numbers (each using two font sizes) 20 characters of text, two dials (i.e symbols that rotate about some point), 4 bars (i.e rectangles whose height denotes a value)and two static arcs. I'll send you an invite to the project dropbox once I've set it up.
In the end though, it comes down to identifying a robust 7" or 10" high luminance display and finding a way to program a controller and send data to several of them independantly.
Bluetooth souds interesting, but you'd probably need a wired circuit for power anyway, so a wired network for data does not lose you anything.
How would I set about getting inside an android tablet? The prices seem to vary from£20 to over £150!
Or would replacing the Newhaven screen controller (SD1963 based) http://www.newhavendisplay.com/nhd70800480ef34-controller-board-p-7308.html (http://www.newhavendisplay.com/nhd70800480ef34-controller-board-p-7308.html) with a controller that was also an Arduino shield like the one in your Arduino Uno R3 graphics accelerator shield article http://andybrown.me.uk/forum/index.php/topic,28.0.html (http://andybrown.me.uk/forum/index.php/topic,28.0.html) be a better way to go?
Right now I'm using the Nerwhaven display and controller simply because it's the only thing I've found that claims tio be robust, waterproof and sunlight readable...
Cheers
Peter