opengauge development: gunio technical considerations

[dcb]

Originally Posted by larrydag

I quickly mocked up a possible pcb mock up for an arduino shield

Cool, having a shield as an option would only increase the appeal of the project. Not everyone likes my "sticks and mud" approach to assembling devices I'm sure

P.S. The serial board seems to work fine too (took 10 minutes to swap over):
P.P.S. I reoriented the buttons so that I am pushing down on them. I got tired of pushing my guino around the desk when I pressed a button

[MetroMPG]

Nice, Larrydag.

Sticks and mud rule, but that's neat too. FYI for any others who don't know what a "shield" is (I didn't, at first), it's a circuit board that plugs into the input/output pins on the *duino, on which you mount the additional electronic components your project needs.

(Did I get that right?)

[larrydag]

Metro, I'm new to arduino's too but as I've seen you got it correct.

[dcb]

FYI, I did a in car test last night:
http://forum.ecomodder.com/showthrea...5.html?p=24421

Results were promising.

[dcb]

The extra step of unplugging the 5v on the serial duino to program it, and the prospect of a lot of trial and error to get this working right, combined to motivate me to put the 4x20 lcd together with the usb duino.

The 4x20 lcd seems to be working without modification to the code (same pinout as 2x16 too):

Here is the backside with just buttons and lcd hooked up:

[larrydag]

This *duino is above the Opengauge price specs right now but if price is not an option it could be interesting. I can see possible in dash functionality with this microcontroller. I has all the features of an Arduino Diecimila for $45.

http://store.gravitech.us/arduino-nano1.html

[Funny]

[QUOTE=dcb;24873]
The 4x20 lcd seems to be working without modification to the code (same pinout as 2x16 too):


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.

[dcb]

Originally Posted by Funny

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.

[jimboradley]

Did anyone else have trouble uploading code to their boards bought from nkcelectronics? I get LED13 blinking every second when I plug it in, but I don't seem to be able to upload to it. I get an error in the avrdude sync, and I'm not getting any help from the peeps at arduino.cc. Anyone else having problems?

[dcb]

Can you give some more details?
Is it a serial or USB board? Can you send a link to the product from the nkc site?

Is it just the assembled board or do you have the extra guino circuitry hooked up?

The once a second blink is a good sign, sounds like a connection problem.