Serial Board - anyone used OBDII

[scottsta]

I have a serial interface and an old RS232 based OBDII interface.

Any suggestions as to how I capture data from that interface ?

[jason]

"OBDII" as in the car diagnostic technology?  If so, interesting application.  I don't know much about it though.

[wolfgang]

OBDII itself is not a RS232 protocol, its a bus with multiple protocols, so some interface boards convert it to RS232, so you need the information for your RS232 to OBDII converter board to do this. See http://www.obddiag.net/allpro.html and http://en.wikipedia.org/wiki/On-Board_Diagnostics and keep in mind each car manufacturer has implemented on top of OBDII its own custom commands....this is long time research to get some useful info. Most you are interested are custom commands. That's the same as you buy a universal OBDII display, it shows very little, except you buy one specific for your brand of car.
//Wolfgang

[jk2001]

I have a serial interface and an old RS232 based OBDII interface.

Any suggestions as to how I capture data from that interface ?

RS232 OBD-2 interfaces either contain some MCU (like ELM323) or are pass-through, but then support only ISO9141.

Try sending "ATI" to the interface. If you get back only "ATI", then it's pass-through. If you get back identification information (like for modem), then it's ELM-32x.

Anyway, I would recommend getting some USB OBD2 interface, such as http://www.obdtester.com/elm-usb. Serial interfaces usually do not support CAN-BUS and have problems with timing. There is a lot of programs that work with it, http://www.obdtester.com/obdtester and open-source pyOBD: http://www.obdtester.com/pyobd