OBD MPGuino gauge

[Froggy]

I was sort of hoping to use CAN in OBDuino as there are schematics for three interfaces (ELM, ISO and CAN) to connect with. It looks (in the OBDuino code) that connection for ELM is established at 9.6k bps instead of 500k bps that CAN uses. Not sure on how ELM to CAN communication would function. (Does the ELM chip broadcast at 500k for CAN, then respond at 9k to the OBDuino?)

[hummingbird]

Guys, I would be interested in an ISO9141-2 based solution. I happen to know a professional PCB designer. If there is a schematic, I can probably get it laid out professionally, and if things work out, can put together a kit using SMD components, so that the unit is only as big as it needs to be.

Can you point me to the schematics please?

[dcb]

Froggy, I have discussed the can specific stuff with mags and I think something will get released, it is just a matter of timing. I've learned that open hardware is tricky and have shared my experience with him. But in a nutshell:

When you do *everything* out in the open, other people move in on the hardware side and while you are busting your butt making things work, they focus on the only money making angle of it. And the project bleeds as the first in with the hardware makes off with the most mula and the project champions are left supporting who knows what just so the project doesn't get a bad name.

On the other hand, this has been done under an "open" premis, so I'm pretty sure mags will release something for the diy crowd but he wants to be ready to go with a hardware offering first.

Keep me honest here mags

[Magister]

Originally Posted by Froggy

Does the ELM chip broadcast at 500k for CAN, then respond at 9k to the OBDuino?

Yes, but the ELM speed on the serial side can be changed too, I tested 38400, I know you can push it to 115200 too and others speed.

Originally Posted by hummingbird

Can you point me to the schematics please?

We never made an eagle schematic of it, you can base yourself on the MPGuino .sch to add the MC33290. We started all this with an Arduino or clone and as for ISO it's just a chip an a resistor, it was easy to do for the DIYs people.

Originally Posted by dcb

Froggy, I have discussed the can specific stuff with mags and I think something will get released, it is just a matter of timing.
On the other hand, this has been done under an "open" premis, so I'm pretty sure mags will release something for the diy crowd but he wants to be ready to go with a hardware offering first.

You are right, to use the MCP2515/2551 I had to change the pinouts of the LCD, and I also rewrote part of the *duino libs to reduce size, and lastly I changes the LCD part to use one from NHD that use a 20mA LED so no need of sinking with a transistor. I also had familial matters that made me busy for a couple of months lastly :-/

I also learned Eagle and the schematic is quite stable now and I am working on a PCB design.

[Froggy]

Thanks DCB and Magister.

I think I see where things are right now. The ISO interface sounds very simple to do, even though it takes a hit on the communication speed. I think I will try that to get the ball rolling on my project.

On a different subject, the current build of OBDuino (1.27) does not compile in the current Arduino environment (1.15). The compile finds conflicts with the serialBegin(), serialWrite() and serialRead() functions. Version 1.14 of Arduino compiles ok (HardwareSerial.cpp was changed between 1.14 and 1.15).

[dcb]

Yah, gotta get this project away from arduino too probably. Don't get me wrong, arduino is completely awesome, but it is for making simple tasks easy to write, not for making complicated tasks easy to maintain.

[Magister]

I agree, the problem also is they change the GCC version to one that does not optimize, this is why I still use the "old" GCC from arduino12, I save about 1250 bytes!

[Froggy]

Ohh yah!

obduino32K

A new version of OBDuino for the bigger chip, and it is supposed to compile with the latest Arduino software. I could only get it compiling by replacing Serial.print() with Serial.write().

[Update] Oddly, I refetched the same file (v. 1.31) and it compiled ok.

[Magister]

electromike is doing a great job enhancing the code!

[electromike]

Yeah, i will start adding some new stuff again soon. I was working on making the module smaller.
I had it neatly added to a snack size rice crispy box. Looked pretty sharp actually. But it was too big. And I don't think my wife liked people always admiring it, it was quite noticeable.
But since I ordered some 328 chips, I decided to just throw them on a small proto board. Now it is the nice size of just being 1cm thicker then the actual display with an integrated magnet so it stays in place on the dash!

I am sure we can come up with some fun ideas for this project. A great foundation is already laid with it being a consistent, cheap, and geeky module.