Forum >OBD2 Questions
OBD2 Questions
Wilksey 2013-11-28 12:41:31 5302 Views3 Replies Hi,
I hope you don't mind me emailing you, but I wondered if you would mind assisting me / pointing me in the right direction with a few questions regarding OBD2?
First of all I know I can buy tools to do OBD2 interfacing but I would quite like to learn to do it myself, and although there is a lot of resources on the internet I don't know how much of it is relevant / true.
I have a 2006 Vauxhall / Opel Astra which has no temperature gauge as in their wisdom decided to leave it off! So I wanted to build my own with a 7 seg or LCD display. My girlfriend has a 2009 Toyota Auris and I want to interface with the CAN bus to make the doors automatically lock above a certain speed and unlock when the ignition is off.
Of course, the easiest way to develop would be with a simulator, which would be ideal for commercial stuff, but I don't want to spend a fortune on simulators which are closed / proprietary just for something at a hobby level.
I came across your page and hoped from the name there would be something free to download / build and use, but I can't see anything available for free so I am guessing you have not released any of the OBD2 stuff as free?
My questions are as follows:
1. What kind of hardware do you use in your simulator and interface dongle? i.e. do you use the Elm327 for example?
2. What would I need to do to build a simulator? Is it the reverse of the dongle, by that I mean writing the responses rather than the requests on a bi-directional bus?
3. I understand there is several protocols, VPW, PWM, K+L Line and CAN Bus, The CAN hardware looks fairly straight forward with a Microchip BUS transceiver and PHY, but what is required for the other protocols?
4. Are the request codes the same? Wikipedia just lists that you can send PID's as bytes such as 010D, is this it or do you need to add some more bytes before to do some kind of handshaking?
5. Is there any site / document that fully defines (correctly) the OBD2 protocol?
6. Am I over simplifying it by assuming that once the hardware interfaces are done and programmed that the code to handle the PID's and DTC's are identical?
I understand that you may want to keep the information close to your chest as no doubt you have spend a lot of time producing something that works, but any assistance / help / guidance would be greatly appreciated!
Kind Regards
I hope you don't mind me emailing you, but I wondered if you would mind assisting me / pointing me in the right direction with a few questions regarding OBD2?
First of all I know I can buy tools to do OBD2 interfacing but I would quite like to learn to do it myself, and although there is a lot of resources on the internet I don't know how much of it is relevant / true.
I have a 2006 Vauxhall / Opel Astra which has no temperature gauge as in their wisdom decided to leave it off! So I wanted to build my own with a 7 seg or LCD display. My girlfriend has a 2009 Toyota Auris and I want to interface with the CAN bus to make the doors automatically lock above a certain speed and unlock when the ignition is off.
Of course, the easiest way to develop would be with a simulator, which would be ideal for commercial stuff, but I don't want to spend a fortune on simulators which are closed / proprietary just for something at a hobby level.
I came across your page and hoped from the name there would be something free to download / build and use, but I can't see anything available for free so I am guessing you have not released any of the OBD2 stuff as free?
My questions are as follows:
1. What kind of hardware do you use in your simulator and interface dongle? i.e. do you use the Elm327 for example?
2. What would I need to do to build a simulator? Is it the reverse of the dongle, by that I mean writing the responses rather than the requests on a bi-directional bus?
3. I understand there is several protocols, VPW, PWM, K+L Line and CAN Bus, The CAN hardware looks fairly straight forward with a Microchip BUS transceiver and PHY, but what is required for the other protocols?
4. Are the request codes the same? Wikipedia just lists that you can send PID's as bytes such as 010D, is this it or do you need to add some more bytes before to do some kind of handshaking?
5. Is there any site / document that fully defines (correctly) the OBD2 protocol?
6. Am I over simplifying it by assuming that once the hardware interfaces are done and programmed that the code to handle the PID's and DTC's are identical?
I understand that you may want to keep the information close to your chest as no doubt you have spend a lot of time producing something that works, but any assistance / help / guidance would be greatly appreciated!
Kind Regards
2013-11-30 18:38:06 Stanley,
I did clearly state that that's what I "thought" the page was about, not that you had in fact claimed.
I do not doubt your contributions to the community, I was of course mistaken in thinking that all of the project was open source. I have not "distorted" any project that you have done, I do not quite understand where you get that impression from.
I have done quite a bit of research, but maybe I am not searching for the right thing, kind of where a pointer or two would have been appreciated, and I have not got a complete picture, so maybe the information was out there but now is lost or under different search conditions to what I am entering.
My own contributions to the community is freedom of information for topics that various folk are stuck upon for which I spend time researching and helping with, quite a lot of it results in people never coming back with their final solution, but the information is none the less there for others to use as they see fit, I don't claim things are my own if they are not and I also do not make profit from any research that I do for the community forums, unfortunately as I am finding out, you don't always get back what you put in. Wilksey
I did clearly state that that's what I "thought" the page was about, not that you had in fact claimed.
I do not doubt your contributions to the community, I was of course mistaken in thinking that all of the project was open source. I have not "distorted" any project that you have done, I do not quite understand where you get that impression from.
I have done quite a bit of research, but maybe I am not searching for the right thing, kind of where a pointer or two would have been appreciated, and I have not got a complete picture, so maybe the information was out there but now is lost or under different search conditions to what I am entering.
My own contributions to the community is freedom of information for topics that various folk are stuck upon for which I spend time researching and helping with, quite a lot of it results in people never coming back with their final solution, but the information is none the less there for others to use as they see fit, I don't claim things are my own if they are not and I also do not make profit from any research that I do for the community forums, unfortunately as I am finding out, you don't always get back what you put in.
Wilksey 2013-11-30 15:52:46 Stanley,
With respect, I am not asking you to "teach" me, I was merely asking for perhaps some more detailed information or even some resources into where you got your information from to build your own, I do not mind doing the electronics or software myself.
I was referring to freedom of information rather than giving items of possession away, which after all is what open source is all about, which is what I thought the page was referring to.
I am not out to offend or anger you, I am just after some more detailed information to get me started, the simulator was an interesting prospect as it would aid in developing the reader.
Regards Wilksey
With respect, I am not asking you to "teach" me, I was merely asking for perhaps some more detailed information or even some resources into where you got your information from to build your own, I do not mind doing the electronics or software myself.
I was referring to freedom of information rather than giving items of possession away, which after all is what open source is all about, which is what I thought the page was referring to.
I am not out to offend or anger you, I am just after some more detailed information to get me started, the simulator was an interesting prospect as it would aid in developing the reader.
Regards
Wilksey 2013-11-29 17:48:17 Stanley,
I can tell by your responses that you are not exuberant with information or explanation of your device(s), which I can understand to a certain degree, it seems anybody who has remote success with creating an OBD tool is keeping whatever information they have very close to their chest.
The hardware side of things I can get the information from the ELM datasheet, which isn't an issue, I have done quite a bit of reading and searching on the web I have drawn the conclusion that yes the information is available at cost from the SAE people. Unfortunately, like many others, I do not have $$$$'s to spend on documentation for a hobby level project, commercial ones might be different.
For example, there is mention of VPW, PWM at 10.4khz, and then another PWM at 40khz, then there is ISO K + L and KWP2000 (2 Different types I understand?). It seems that if I wanted to use this for other vehicles for members of family I would need to utilise all protocols as I do not know which ones are available as some are different that others pre 2008.
I was hoping to use a piece of Vero type board with a few chips and components on and just build a small display device which has the information on without the need for a "kit" as such, as they are big and bulky and not that easy to hide away.
I presume once you get either a reader or simulator working the interface is the same and the protocol is similar with their own response codes (which I guess are outlined in the expensive documents available to purchase).
I was hoping for a bit more seeing as the things that jump out are "FREE matics and Open Source", but as I say, I can in a way understand the reluctance to open the information. Wilksey
I can tell by your responses that you are not exuberant with information or explanation of your device(s), which I can understand to a certain degree, it seems anybody who has remote success with creating an OBD tool is keeping whatever information they have very close to their chest.
The hardware side of things I can get the information from the ELM datasheet, which isn't an issue, I have done quite a bit of reading and searching on the web I have drawn the conclusion that yes the information is available at cost from the SAE people. Unfortunately, like many others, I do not have $$$$'s to spend on documentation for a hobby level project, commercial ones might be different.
For example, there is mention of VPW, PWM at 10.4khz, and then another PWM at 40khz, then there is ISO K + L and KWP2000 (2 Different types I understand?). It seems that if I wanted to use this for other vehicles for members of family I would need to utilise all protocols as I do not know which ones are available as some are different that others pre 2008.
I was hoping to use a piece of Vero type board with a few chips and components on and just build a small display device which has the information on without the need for a "kit" as such, as they are big and bulky and not that easy to hide away.
I presume once you get either a reader or simulator working the interface is the same and the protocol is similar with their own response codes (which I guess are outlined in the expensive documents available to purchase).
I was hoping for a bit more seeing as the things that jump out are "FREE matics and Open Source", but as I say, I can in a way understand the reluctance to open the information.
Wilksey 