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Topic: Possible to "turn on" an arduino via a touch on a touchscreen? (Read 1 time) previous topic - next topic


I think I've seen such a library, have a search through the playground and libraries areas.

Rob Gray aka the GRAYnomad www.robgray.com


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..

An ATmega8 only has 8 KB of memory available for programing.  It might be possible to do most or even all of the things you describe, but you'd have to have very efficient code.  Even if you save 0.5 KB not having an bootloader and used a ISC programmer (again something I don't recommend a novice start off with) instead of using the code directly from the computer running the Arduino IDE, I doubt you could take advantage of most libraries.  This is because most are written to prioritize ease of use, rather than efficiency.  Also there's the whole issue of including a stable clock (since you are going to be doing serial communication) and voltage regulator circuitry.... 

It would be analogous to throwing someone who doesn't know how to swim off a diving platform into 20 feet of water.  It's possible for them to learn quite a bit, but even if successful it will likely be a stressful and unpleasant process.  I like your enthusiasim, but when you are starting-out there's no need to make things more difficult than they need to be.  So, I strongly recommend you use a proven development board design, like the Uno, before attempting making completely custom microcontroller board.

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.

Off the top of my head I don't know of any, but something like that is certainly possible to do.  Personally though, I'd just spend a little extra on a display that already has a controller capable of at least one type of serial communication even if it's just basic serial data at a standard speed (i.e. not a specific protocol like SPI or I2C).  IMHO, the delay and hassle avoided will be worth the extra $10 to $25 you might have to spend.

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