Now, the question that i have is would it be possible to remotely turn on the arduino by touching the screen? Basically, i would wire the arduino to only come on while the ignition is on, but then also come on when i touch the screen - for x seconds. Is this possible? if not, would leaving the arduino on,but turning off the LCD/everything, would this be too hard on the atmega? I don't think that would be too big of a load for my batteries, just wondering if the chip can handle being on constantly. Or could the arduino be put in "sleep" mode.. then woken up on touch?
I realize this project is probably WAY over my head, but I'm up for a challenge.. If it's too much, I'll end up just using this 16x02 lcd display to monitor egt's and a few other engine perimeters i can find/tap into. But i just think a small touchscreen would look SICK.
I would just make sure you get one that has good supporting documentation, along with examples or tutorials about how to intereface it with microcontrollers.
I also have an atmega8 here, was like $3 on ebay.. Would this be large enough to hold a sketch to control a good bit of stuff? I.e., running the lcd, controlling a few relays via input from the lcd/throttle position sensor/some other engine parameters, running the max6675 + k type tc, also possibly controlling when the torque converter locks up / overdrive for the transmission..
One last question, if i get a touch screen display that doesn't use SPI(?) or i2c, are there any libraries that are out there where i can use a shift register(s) to lower the number of pins needed? Now i've got a 74hc595 running a 1602 lcd with a new liquidcrystal library someone else made.