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Forum Index : Other Stuff : Car Onboard Diagnostics
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| MOBI Guru  Joined: 02/12/2012 Location: AustraliaPosts: 819 |
Hello all, I'm not sure if this should be in this forum or EVs etc or even at all, but.. I have collected a lot of data on OBD but not had too much time to chew through it all. I'm pretty sure that with dedication I could come up with a reader starting from the ground up. Has any of TBS members had a play in this area. A bit of mutual discussion would probably give me the incentive to continue. David M David M. |
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yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
I do a bit of stuff with industrial and agricultural gear, but that is all a bit secret squirrel, not really appropriate for a public forum. The best I could do is point you towards the ELM327 V1.4b this little chip is the standard for most of the modern OBDII comms protocols including canbus. It basically converts the data stream to RS-232 (serial). There are interpreter kits and plans around some are good, most are junk. The quickest route to OBDII data is scantool interfaces and some free software on the laptop. If you are looking to work with older (mid nineties) or proprietary data there is a lot of trial and error involved. I'm confused, no wait... maybe I'm not... |
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| MOBI Guru Joined: 02/12/2012 Location: AustraliaPosts: 819 |
Hi, Thanks for the links, I'll certainly have a look (if I haven't been there already). My preference and yes, I know it takes a lot of trial and error, is to build things from "first principles". It takes a lot of research and I get to learn lot more. (it also keeps the ageing brain cells from going too rusty). Its not that I want or need a "scantool", I just want to get one going that I can modify to suit my requirements. I did the same thing with a 125KHz cattle eartag reader i.e. got it working using "discrete" chips with Picmicro heart and i2c interfaces and then got a TI chip that did all the rfid part. (I still need to "bluetooth" it). David M. David M. |
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muddy0409 Senior Member  Joined: 15/06/2011 Location: AustraliaPosts: 125 |
Are all OBD connectors standard or do different car manufacturers have their own particulay shapes & sizes? Don't poo poo conspiracy theories. Remember that everything ever discovered started somewhere as a theory. |
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| MOBI Guru Joined: 02/12/2012 Location: AustraliaPosts: 819 |
They used to be different sizes in the very early days but seem now with the OBDII version, to have hit on a common (I think 16 pin) interface. Plugs, sockets and leads to connect from the car to the pc or other are all available on ebay quite cheaply. The protocol is also pretty standard these days also but there are still at least two formats being used. My reading of the subject hasn't been too 'in depth' yet as I'm still in data gather mode. Have you had anything to do with OBD? David M. David M. |
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| yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
I remember my first scan tool, had to manually enter an ID code to poll the ECU for real time data. The data for that ID would come back as HEX which had to be converted to decimal then scaled for what ever unit it was supposed to represent. I threw it very violently in the bin and stomped out of the workshop. returned 10 minutes later, fished it out of the bin, saved the cable, belted it with a hammer and threw it back in the bin EVEN MORE VIOLENTLY THAN THE FIRST TIME. 
My dad thought it was hilarious. I'm confused, no wait... maybe I'm not... |
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| MOBI Guru Joined: 02/12/2012 Location: AustraliaPosts: 819 |
Hmmm. That doesn't engender a lot of confidence in one. Never the less, I'll press on until it gets too hard. Nothing ventured.... I wish I'd been there at the time - I know the feeling. David M. David M. |
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