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by oxo » Wed Jun 20, 2012 8:51 am
http://www.obdsol.com/stn1110 is an IC that can interface to an OBD-II connector in yr car and also to a raspberry pi

I received 2 dip's from obdsol.
If someone in EU can show progress in using them, I can send one.

My own site for my project is http://owen.brotherwood.biz/bilberry-rasp

The STN1110 will be build as a daughterboard on the pi...
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by oxo » Tue Jul 03, 2012 5:06 pm
The spare STN1100 has found a productive new owner in the north east of england
- on it's way from denmark soon
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by TonyD » Wed Jul 04, 2012 12:37 pm
Thanks oxo.

I'm looking forward to building a OBD interface for the RPi. :-)
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by Wolfram23 » Fri Jul 20, 2012 7:03 pm
Hi, newbie here. What is the point of this/these chips? Why not interface with the standard OBDII output? Would you not simply require a software that can read the data? I've seen many adapters (even DIY instructions) on making the ECU/OBDII plug to a USB.

I tried some googling but nothing was really explaining what the benefit of the STN1110 is.
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by jan77 » Fri Jul 20, 2012 9:39 pm
Hmm. That's right, what do you think is the benefit of OBD? I mean, on board diagnosis is only possible if line 15 (key) is switched *off*. At 15=on you'll only receive some useless "standard" information.
The only interestening point would be to build a diagnosis interface, but such are cheap to get, so why do you want to build smth. like that?

You cannot get *any* CAN message via OBD, and even if you connect a CAN gateway or use similar interfaces, you can't decode these messages without a DBC for this specific car/platform (can data bases) which are the holy secret of every automotive company ;)

However, i'm interested in your project - so what do you wanna build?
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by Wolfram23 » Fri Jul 20, 2012 10:40 pm
I'm imagining having pretty much all the readings availalbe, like Air-fuel ratio, MAP, temps, pressures, whatever. Something like this, I guess:

I also like the efficiency/MPG reading.
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by jan77 » Sat Jul 21, 2012 12:15 pm
i don't know what you really want to build, but http://en.wikipedia.org/wiki/OBD-II_PIDs shows off the standard information available through OBD-2. To build a visualization for voltages, some pressures, a very few engine data it should be enough.
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by oxo » Sat Jul 21, 2012 7:02 pm
One can do what one wants with the interface: now there is at least 2 "working" on an integrated circuit for the Pi.

On the question of what benefit the STN (or original ELM) device is that it creates an "at" command set interface with the OBD-II. The device does all the grunt work with the OBD-II protocol.

An external interface is always possible for under 50 dollars, but where is the fun in that: depends on costs of the needed components for the integrated solution.
External interfaces can be interesting. Note that an iOS device supports wireless but not BT and an Android only supports a specific type of wireless but supports bluetooth.
One has "total control" of the pi and can make the serial communication from the STN available in both formats: something not normally used in cheap external interfaces.
Then y just need software that works : the most common command sent is to query which trouble codes are present on the car. One has a little calculation to decode the reply.

For my own project, I have an older pre-OBD-II car, so my interface will be ALDL but that is another story
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by Wolfram23 » Sat Jul 21, 2012 7:18 pm
Thanks for the feedback guys. Certainly a start. Oxo, any chance you could share where you see these working OBDII - RPi interfaces? I'm definitely out of my element/experience here if I have to manually interface with the OBDII even having that Wiki article, so it would be a great help to see how other people are doing it.
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by oxo » Sat Jul 21, 2012 7:25 pm
One could expect a mother board for the pi with a 9 pin d connector to which one attaches a cable to the obd-ii interface in ones car.
One can then connect to the car via a terminal program from the pi to send simple messages to the car using "at" commands. http://elmelectronics.com/DSheets/ELM327DS.pdf see page 29.
Latter, someone may port 'c' code or python code ( http://symbtelm.moxoed.com http://symbtelm.moxoed.com/user )to create a library of standard command/response interpretation.

Given that the device is permanently attached to the car, "other drivers" that may not notice a red light don't have to send an SMS asking what they should do after it is too late as it is possible to send the problem via "something" to oneself ...

ELM 327 was the original OBD-II "at" interface device.
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by Wolfram23 » Mon Jul 23, 2012 2:59 pm
Learning so much here. Really great.

So, I found an open source software called pyOBD (written in Python) that can interface with, apparently, any ELM chip:

There's also some great info here on making your own board to interface with it, as well as other software.

I'd love to hear if anyone is interfacing with their ECU on an RPi and how they're doing it.
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by oxo » Mon Jul 23, 2012 3:09 pm
Symbtelm was written in python as well:)
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by Wolfram23 » Mon Jul 23, 2012 10:23 pm
As I research more, and think about it, I'm starting to feel that I should buy an Arduino as there are already many people successfully interfacing with their ECU and using LED displays to readout information. It's exactly what I want, and I'm thinking it might even be better overall to leave the Pi with Music and GPS, especially since I'd probably want GPS and the OBDII data displaying at the same time.

Now to figure out the cheapest way of doing it! Buy an STN1110, or an ELM323, and I need a PCB layout plus what components to buy, etc... ahh the fun of modding.

oxo, I found someone with your username coming up a few times in the Arduino/OBDII discussions :)
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by hsiboy » Thu Aug 09, 2012 12:06 pm

i'm very interested in sharing what you learn.
I have already made a start using an ELM327 based USB "scan tool", however because i drive a Ford, much of what i want access to isn't available via a regular ELM327 tool, and i have made a modification so that i can access the MS-CAN (mid speed CAN) bus.

My goal is a black box "flight recorder" for my car.

This last month i have purchased a TP-Link WR703N 150Mbps Mini WiFI 3G Router, and flashed it with OpenWRT, this coupled with a 3G dongle, has given my car wifi and a network port for the Pi, ergo, my car is online, and send data home.

I'm currently working my way through the maze of Ford specific codes on the bus, and most of my help so far has come from Russian hackers who have made great progress in this space (god bless google translate).

I've not looked at the STN1110, so i'm very interested to see how you progress.

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by rapzak » Tue Oct 23, 2012 12:03 pm
Hi, Hsiboy

Can you share some of your work?
is it standard OBD2 protocol or the custom you have got working

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by hsiboy » Tue Oct 23, 2012 12:21 pm
Hi Kasper,

much of my work has been spent on the hardware, the TP-link router and Pi, and working around issues to do with the drop in voltage during engine crank. Having the Pi brown out isnt good.
I drive a diesel, and son on cold mornings i may need a 30 second crank, so my initial idea of using a capacitor has reached an expensive conclusion. I'm now considering a LiPo battery, that is then charged by the vehicles 12v supply, coupled to a watchdog to power down the Pi when the LiPo runs low.

In other news, i received a sample STN1110 to play with, and so far its command compatible with the chip i had in the cheap eBay OBDII lead, so i haven't had to modify any scripts yet.

The core system is based on Debian, and the logic is mosltly perl (perl is built for parsing and reporting data, so seemed appropriate)

I will pull together a write up, and put the source up on github once the system is stable.

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by syndicate » Tue Nov 20, 2012 12:46 am
Hello all,

I would like to offer some help for anyone trying to build an interface to the STN1110 and RPI. I'm currently designing an interconnect board that can be potentially interfaceable to the RPI using some new modules from OBDsol. One of the most difficult parts of getting this together is driver modules, and also using some driver modules that are not OBD2 compatible for some cars i.e. single-wire CAN (GM LAN) and Medium Speed CAN(Ford). Here are some pictures of the modules I've designed that include the new STN1170 which communicates to all OBD2 standard protocols and single wire and medium speed CAN. The STN1170 will solve some problems that the STN1110 cannot do. I have a simple sparkfun FTDI that allows me to successfully send commands to an ECU using all standard OBD2 and some OBD1 protocols. If any of you have questions, I'll be happy to try to answer them.


OBD 2 PDIP Modules
obd_PDIP_modules.JPG (54.74 KiB) Viewed 27059 times
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by syndicate » Tue Nov 20, 2012 12:56 am
Heres the board powered through the OBD II breakout connector. Would be great if I can make an interconnect board to have this thing power the RPI too. Just can't connect a USB cable at the same time. *shrug*.
obd_PDIP_modules2.JPG (36.61 KiB) Viewed 27056 times
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by Wolfram23 » Fri Nov 23, 2012 6:25 am
That's impressive! I just ended up buying a cable, OBDLink SX (on sale, $78 including S&H) which is STN1110 based. It was plug and play with the Pi. I managed to read some values off my car today using minicom.

Still a lot of work to get it showing up on the LCD, but so far so good. I'll continue checking out this page, very interesting work.
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by hsiboy » Fri Nov 23, 2012 11:46 am
Hey, that's some good work right there! i haven't worked with the STN1170 because of the package. For me the magic sauce in on the Ford MS bus, so i'm interested to see how you get on.

Did you use a reference design for the STN1170 PCB or is this homebrew?


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by syndicate » Fri Nov 23, 2012 8:23 pm
There is a reference schematic for the 1170 of which I will post soon today.
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by syndicate » Sat Nov 24, 2012 7:24 am
Here are the eagle files I've created based off the reference schematic in the STN1170 datasheet. There is a bit of difference because this is a standalone 44-PIN PDIP module. Meaning you can leave the pins connected or unconnected and it doesn't matter if the pins are open drain or not. You will be able to purchase these modules from ScanTool.net soon as they are still under QA testing. Also coming soon is an interconnect board that allows all 3 of those modules to be plugged in, and with breakouts for probing on each pin.

Merry Christmas and have fun!

(42.53 KiB) Downloaded 554 times

Here is a sneak peak of the breakout board:
interconnect board
interconnect_module_board.jpg (39.36 KiB) Viewed 26849 times
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by syndicate » Wed Jan 30, 2013 12:05 am
Here is an update on the development board for the STN1170 chip. It supports Medium Speed CAN, J1850 PWM, J1850 VPW, ISO, High Speed CAN, and Single Wire CAN. I'm thinking of holding some sort of raffle for the first couple boards that pass QA. If anyone is interested just PM your email and I'll put you in for a chance to receive a free development board. Can't wait to start interfacing this with the RPI :)
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by jfornango » Sat Feb 02, 2013 4:41 am
Syndicate, that is a spiffy piece of development work.
Just out of curiosity, what would this board be retailing for?

I've been thinking of something like this as a possible Pi project, though I was looking at the display and command interface, rather than the hardware side. Some slick graphics for a small screen (either DSI or Composite), maybe a touchshield from Arduino?
I'm only wearing black until they find something darker.
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by syndicate » Sat Feb 02, 2013 7:10 am
Not sure yet on a price. I know the company wants it as cheap as possible to allow developers to purchase it with ease, but I really can't even give a ball park price. If you PM me your email address I will opt you in a raffle for receiving one for free though! :) Right now I'm doing app notes on the datasheet and some sample code, though it's pretty self explanatory even in wiki http://en.wikipedia.org/wiki/OBD-II_PIDs
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