Help sorting out base level computer system.

I was browsing the forums today and I came across this thread (Link) about the Raspberry Pi. It is a very small ARM based computer, it only runs at 700mhz but this seems ideal for controlling the Arduino and I think it would be much easier than trying to run a GUI from the Arduino. The only concern I have is how the Arduino will be controlled from both computers, my initial thought is to make the Raspberry Pi a USB device on the main level computer, but I don't know how this would be done. Any input or ideas on how to do this?

that is all very doable, i believe with an uno but def with a mega.

as far as the smart gpu. i emailed them about a transflective screen and got this reply, which you may find useful:

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Dear Scott:

Our SmartGPU has a high resolution LCD display with high brightness, however we think is not at 100% sunlight readable, it's about 80% sunlight readable.

However, the "SmartGPU" is a graphic chip processor, that it is connected to our LCD. So you can design with this processor by now, and later on just connect it to a sunlight readable LCD instead of ours, the Smart GPU is compatible with any 8/16 bit parallel LCD. We don't offer our SmartGPU board connected to a sunlight readable LCD because as you know, cost would increase a lot, and we want to keep it low cost.

Some people has bought the SmartGPU board to develop their application, and later on, they buy us just the Graphics processor chip and they connect it to their custom LCD(bigger size, Sunlight readable, different resolution, etc).

Actually what we sell it's the SmartGPU chip processor and it's technology, but to demostrate the performance and characteristics of it, we offer the SmartGPU development board connected to a normal TFT LCD.

Hope this can help you, feel free to ask us anything else!

Best Regards
David Sullivan

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you could always go with a smaller low resolution display and attach a touchscreen to it for under $30 (that's what im doing right now)
i dont know if i'd go the pi route if i were you. all that you are trying to do is well within the grasp of the arduino.

you are only asking for 6 analog and 5 digital inputs. your most challenging task is an engine start function. you'll have to (if you want to do it correctly) read the tach wire to stop the cranking when the engine turns over. I'd recommend; to make your life easier, to get one of the remote car starter modules and trigger that from the arduino (one digital pin to trigger the module and then a second digital output to override the timer function by keeping the relay charged)



i posted a video of my v01 touchscreen in my boat worklog thread if you want to see what the display looks like.

Reading the tach for the start function shouldn't be to hard, I can get a signal from the tach output on the MegaSquirt. I like the screen you have in the video a lot, its about the right size, but it looks like the resolution is a bit on the low side for what I wanted to do. I think for the GUI I would put the temps scrolling across the top of the screen then a row of indicator icons then the controls below that. controls would be something like up and down arrows for the windows (one set on each side), the start button in the middle (inverted colors when the car is running), and the buttons for the lights between the start button and the window buttons.

there are a ton of screen options, some with a lot higher resolution and full color. I have some very specific limitations being in a boat. there will be times when there isn't an option for shading the screen. i needed to go with something that was sunlight readable. hence my compromise for resolution.

you may be able to use a transmissive screen (like most lil/xenarcs) like this: http://vizictechnologies.com/#/development/4554296549
it takes care of all the processing so your arduino just tells it what to display, where and when.

you can also shop around for different screens. as long as its an 8 or 16 bit parallel screen. the gpu should be able to control it

After looking around some more, I think I will be able to get by with a character type LCD display. These seem to be very easy to control with the Arduino, and I really like the RBG back-light ability. My only concern is the touch capability of these displays, I was unable to find a touch controller that could be used with the Arduino. Dose anybody know where such a thing can be found?

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Originally Posted by BoyRacer0013

After looking around some more, I think I will be able to get by with a character type LCD display. These seem to be very easy to control with the Arduino, and I really like the RBG back-light ability. My only concern is the touch capability of these displays, I was unable to find a touch controller that could be used with the Arduino. Dose anybody know where such a thing can be found?

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I get nearly everything from adafruit. They have a nice 4 wire resistive panel with an adhesive back. Works great. And fits the 128x64 screens nicely.

One thing you have to figure out with the glcd screens is if you should use a serial or parallel.

Are you running a 128x64 screen? What are the differences between parallel and serial screens?

i am running the 128x64

the differences are the amount of ram they require, the speed and the amount of pins used.


the serial are a bit slower (though i dont think you'll notice the speed for what you want to do), it uses more ram (1kb buffered), and uses less pins (usually 4 or 6)
im using a serial and it's working great. i have it hooked up to a thermistor right now and it updates the values on the fly. so speed isn't a hindrance.

Serial is probably best for me then, and I really like the negative version of that display. I had an idea to run two separate displays, one with time, heading, passenger window control, and sub menus for the interior lights and temps. The other display would have a home menu that would have driver window control and the indicator icons and sub menus that would control the show lights, interior lights, both windows, and be able to display temps, time, and heading. Could this be done with a single Arduino Mega?

:) you are following in my exact footsteps. unfortunately you can't have multiple instances of that display using that library as it is. you'd need to run a second arduino. (you can have them talk to each other though). i'm planning on running my mega as the master and possibly the nano as a slave; though, im not sure i need to have the two talking to each other so that may simplify things.

one thing about the negative display, it may not be as user friendly in direct sunlight. if that's a concern for you