My home-brew Arduino OBD-II connection kit

After many attempts to connect an Arduino with my car through the OBD-II port and having some success, I’ve finally made a kit which enables those who want to playing with Arduino and their cars to jump start quicky.

My Arduino OBD-II Connection Kit consists of a modified ELM327-compatible adapter which can be wired with Arduino or other MCU boards. The adapter also provides 5V power supply, which is ignition controlled (put through when engine starts and cut off when engine stops). This can provides power (up to 500mhA current, with reverse protection) for Arduino board, shields or some other attached devices, so a wire getting power from somewhere else is not needed. This helps to make the gadget you made looks tidy. The only interface to the car of the adapter is the OBD-II connector.

http://www.arduinodev.com/wp-content...3/P1040883.jpg

I also developed an Arduino library for the adapter as an open-source project. It provides Arduino developers an easy-to-use APIs to connect to and retrieve realtime data from a vehicle. The data includes:

• Vehicle ID number
• Vehicle speed
• Engine RPM
• Throttle position
• Calculated/absolute Engine load
• Engine coolant temperature
• Intake temperature
• Intake pressure
• MAF flow pressure
• Fuel pressure
• Barometric pressure
• Ignition timing advance
• Engine running time
• Vehicle running distance
• Boost value (estimated)

By having access to these data, the Arduino can compute, store or show the realtime vehicle status in any unique way. Here is a fancy dashboard gadget I made for my car (with video).
http://www.arduinodev.com/wp-content..._indicator.jpg

If you are interested in my Arduino OBD-II connection kit, please see here for more details.

Love it! Thanks for some really good articles and info!

It looks as you're having a Volkswagen, if so have your tried to talk to your display in the dash via OBD/CAN?

Hi Borte, I am glad you like my work.
I drive a Volkswagen Scirocco 1.4TSI. Yes I use my OBD-II kit to pull data out from OBD/CAN.

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Originally Posted by Borte

Love it! Thanks for some really good articles and info!

It looks as you're having a Volkswagen, if so have your tried to talk to your display in the dash via OBD/CAN?

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Have you tried to send data back to the indash display? So that you can show the information you're getting from the car on the display between your rpm and speed?
I've seen some aftermarket units that you can be plugged into the car's can bus that can show some extended information in this display.

That really depends on the type of the in-dash system and has no single standard like OBD-II.

I know it's not OBD-II but the communication is CAN based so I was just wondering if you had given it a try.

I'm actually in the process of working with sending data the the mfd via CAN. The problem I've found is that in my Touareg data is sent to the display differently than in other VW's. For instance my nav and buttons comunicate over the infotainment bus and the mfd updates also go over the info bus but in the golf's and other VW's cluster info is done via the convience bus. Checkout http://secuduino.blogspot.com/ there is a guy who managed to send information to the FIS in his Seat Leon . I brought a cluster to help with my development efforts.

I think I will look into this. Thanks for the suggestion.

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Originally Posted by Borte

I know it's not OBD-II but the communication is CAN based so I was just wondering if you had given it a try.

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This is awesome. So by sending specfic CAN data can let the MDF display custom information? I have a RNS510 on my VW scirocco which I think is quite identy to many VW cars.

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Originally Posted by that_kid

I'm actually in the process of working with sending data the the mfd via CAN. The problem I've found is that in my Touareg data is sent to the display differently than in other VW's. For instance my nav and buttons comunicate over the infotainment bus and the mfd updates also go over the info bus but in the golf's and other VW's cluster info is done via the convience bus. Checkout http://secuduino.blogspot.com/ there is a guy who managed to send information to the FIS in his Seat Leon . I brought a cluster to help with my development efforts.

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Yes it's possible. There are a couple of youtube videos which show some setups but not much on how it's done. There's a lot you can do with canbus. I was able to use my arduino canbus setup to grab steering wheel button presses and send them to the carpc. I also use canbus to tell the carpc when the key is in the ignition and also when the car is in reverse. That's just scratching the surface, there's so much more that can be done.