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Old 05-26-2008, 07:36 PM   #68 (permalink)
dcb
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Quote:
Originally Posted by Funny View Post
I really would like to get started on one of these, even though I have a Scangauge and have a car that runs OBDII.
Do you think it's possible to program a Freeduino, along with an Elm 327 decoding IC, to work with OBDII? What about adding more EEPROM? Is that possible to allow for more code? Just giving ideas for MPGuino 2.0 (3.0?). I think it would be more aesthetically pleasing when using the 20 x 4 to add a space between the readouts and go out another decimal place, just a thought. By the way, this is an awesome project, you are an asset to us Ecomodders.
sure it is possible to interface with an elm chip, I've done it over a serial connection, but it could be integrated certainly. It is also possible to interface directly without elm, but it is a large amount of work and difficult to test properly, and will have lots of bugs. Even the elm folks don't claim 100% usefulness in all vehicles because the obd protocols are a pain in the butt.

I don't know where the 4x20 fits in the plan yet. I really like the small profile of the 2x16 (it is about half the size of a scangauge) so you can usually find a spot in front of your instrument cluster to put it without blocking something important. More data is good, but who wants to design and maintain two different versions of the code to support two different types of displays? And will that complicate things for the folks who are having difficulty with just one version of the code?

The good news is that the code is a bit Object Oriented, so that an advanced user can probably hijack an existing screen or add a new one and display any of the values for any of the trips with a few lcd.gotoXY and lcd.prints and pass in the trip values they want to display as they become available (i.e. instant.mph(),instant.rpm(), tank.dte(),instant.acceleration() ) . The LCD class in mpguino does support 4 lines/20 columns.

edit: the 4x20 may evolve into a configuration setting someday, along with customizable screens.

re: eeprom, it won't make the program space bigger but we could save more data (trips, fuel logs). But we haven't touched the 512 bytes of eprom that we have yet. It has room for 32 trips, or 85 fuel log entries, or some combination inbetween, plus need room for configuration data.
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Last edited by dcb; 05-26-2008 at 08:15 PM..
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