I’d love to see some SparkFun products built around OBD II, the standard car diagnostics computer interface. I think there’s a whole slew of hobbiest, DIY products that could come from that area alone.
This seems like a ripe area for small devices and lots of interfacing possibilities that SparkFun could capitalize on for the benefit of its DIY customers. Here are some OBD-II links to look at:
http://www.obdii.com/links.html
http://www.thinkythings.org/obdii/index.html
Landon
I’ll second this idea. I just bought an OBD2-USB cable, but would love to have an OBD2-serial (TTL) cable. The electronics are right up SparkFun’s alley, but I’m not sure about the connectors and cable assembly.
I’ll third this idea, too. If the OBD2 socket has +12 and ground, then it should be possible to create a self-contained OBD2-to-bluetooth interface. Then the car can be tuned with a bluetooth-capable laptop, or a bluetooth-capable PDA or Gumstix could be used for data logging, minor tuning adjustments, or as virtual guage cluster permanently embedded in the dashboard.
Also, a pointer to an existing cable that supports Japanese cars:
http://www.tactrix.com/product_info.php?products_id=36
And pointers to software that supports the aforementioned cable:
http://openecu.org/index.php?title=Downloads
One of the more annoying things about ODB2 in my car is that the connector is located above my (the driver’s) left foot, and the laptop needs to be in the passenger seat, so the cable gets draped over the steering column. Cable routing is annoying; bluetooth would be sweet.
Hmm, I’ve looked into OBD-II quickly to assess the feasibility of making a cable like this - it looks like there are a lot of different OBD-II electrical interfaces [ http://www.cardlabs.com/CardLabs_obd2.htm ]. Looks like we’d have to make 4 or 5 different cables just to provide compatibility - and with the design time required to design and code for each one - I’m not sure if its something that we could make affordable.
If I’m in error, let me know.
Cheers,
–David Carne
There are existing ODB2 interfaces that support all flavors of OBD2 with a single product, and it doesn’t appear to add a great deal of complexity to the hardware - here’s a schematic I just came across that supports ISO, PWM, and VPW.
http://obddiagnostics.com/schem.html
The notes describe groups of components that are associated with each flavor. It doesn’t support the CAN variation, but 3 out of 4 ain’t bad. 
I’m not sure how much complexity it adds to the software side of things though.
It looks like the ISO-9141 flavor covers most non-US vehicles, and it seems to be what most of the people at http://forums.openecu.org are interested in (mostly Subaru WRX and Mitsubishi Evo owners). ISO is what my Subaru Legacy uses, so naturally it’s all I care about.
http://www.sterntech.com/obdii_protocols_iso.php
But to be fair there are people in the MP3Car OBD2 forum with all sorts of vehicles:
Actually the ELM327 is available with schematics that already supports all the standards.
http://www.elmelectronics.com/DSheets/ELM327DS.pdf
I suspect it’s simply a programmed PIC chip because the pin diagram matches.
The chip documentation includes a sample circuit. All that would be needed is to slap a bluetooth or other wireless circuit on the board.
Yeah, its a PIC18F248 or PIC18F2480. It says it on the bottom of page 4. It would be nice to get the code if anyone has it. Think they forgot to code protect it??? maybe not.
The example circuit isn’t too complex. I would actually build it myself, except that I’m concerned that a mistake would blow out the computer in the car and cost thousands of dollars in repair.
Yeah same here. I don’t want to damage my car. Does anyone know where I can get the specs for the different communications to these computers? I kow there is PWM and VWM, where can I find info on these??
To echo what mzoran said about the elm chips and circuit. It’s very easy for a hobbiest. I have personally built a board for every OBDII chip they make. Great company and very reasonable price. I cleared my check engine light yesterday with it.
Have a look at this:
Basically a whole OBD-2 gateway on a single chip with a RS-232 interface. Not as flexible as a custom implementation, but it provides many of the common parameters.
Ive used these before in the past.