Looking for direction & new to CAN

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#1
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Hi,

I'm looking for some pointers on a CAN project. I recently converted a Ford Focus to battery electric. Now I want to do some real-time monitoring of things the car systems already know.

I want to datalog speed and odometer readings to add to the motor current and voltage I already have. I'm not new to Atmel chips but I know nothing about CAN.

I looking for some pointers on:

1) How to connect to the buss.
2) How to recognize the data I'm looking for.
3) How to avoid stupid CAN start-up problems.

Any help would be greatly appreciated, and thanks,

Tom

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You want to read from the OBD connector under the dash, or right from the ECU? Plan B might be just read the vehicle speed sensor directly with the avr, but you dont learn all about CAN that way.....

Imagecraft compiler user

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OBD isn't only CAN. There are other serial interfaces in it that have nothing to do with CAN.

Here are two Circuit Cellar contest entries that might be of some interest:

http://www.circuitcellar.com/AVR...

http://www.circuitcellar.com/avr...

BTW, did you get rid of the gas engine and ECU?

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I still have the engine, I'm trying to sell it. But the ECU is still in use. It drives the speedometer and tack and other stuff. And, I only have one error code, the fuel pressure is low.

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I thought new cars with CAN have CAN in the OBD connector, and the old pins were obsoleted?

Imagecraft compiler user

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bobgardner,

You are right about the speed. The sender is available and I could use that. But, the problem I see is the odometer data, I believe, is held in the ECU (Ford calls it PCM). So, if I have to get that from the bus then why not get both.

Mike B,

Thanks for those references. I'm worried that the Ford specific codes will be difficult to decode. That's my main purpose in posting, to see if anybody has been there before my humble efforts.

Tom