CanBusExample2

Page last updated 05 Jan 2010, by Kevin Konradt. 7 replies

Important note: DO NOT mess around with the data busses in your car!
The car used in this Example got special ecu's, seperate can busses etc.
..you've been warned.  ;>

A little fun project as an example for the usage of the Canbus.
The distance to an infrared sensor is simply translated to a gas pedal position.

The mbed used in this example is connected to a separate (non standard) canbus in the test car (VW Golf GTI).
A special ecu allows to control the gas pedal based on the received can messages.
A Sharp infrared distance sensor (2D120X F 69) is connected to an analog-in port.
(Note: The usb is only used as power supply for the mbed.)

For further technical reference on the connections, used can transceiver and how to get your mbed on the can bus, see CanBusExample1.

CanBusExample2

http://www.youtube.com/watch?v=rtF5doTyF_4

 

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Sorry for the bad formating and plaintext links, but i can't get along with the editor..!?
editor_usability--;
:(

Update: OK, links working :D

7 comments

Andrew Harpin
03 Jan 2010

You have to type text then highlight to add a link. I put something in the suggestions post.

Kevin Konradt
03 Jan 2010

Cool - That worked, thanks!
But it's confusing.. the editor 'thinks' too much.. ;->

Matthew Shoemaker
04 Jan 2010

Kevin, I wondered if you could tell me how you connected your transeiver to the CAN Bus?  Looking at CanBusExample1 it looks like you just connect the transeiver to the CAN_H and CAN_L pins and you are set.  Is this how you have done it?  I understand you state you are using a seperate non-standard CAN Bus, just I am just curious how you have it connected.

Thanks,

Matthew

Bright Idea
05 Jan 2010

What do you mean by "Special ECUs" ?

Kevin Konradt
05 Jan 2010

Matthew Shoemaker wrote:

[...]it looks like you just connect the transeiver to the CAN_H and CAN_L pins and you are set.[...]

yes. The output lines of the transceiver are directly connected to the bus.

 

Matthew Shoemaker wrote:

[...] using a seperate non-standard CAN Bus [...]

this and

Sean Tate wrote:

What do you mean by "Special ECUs" ?

need a little more explanation:

In the test car are more than just the default/factory-equipped canbusses. There is an additional (/special) ECU (which isn't there in a normal car) connected to a seperate can bus, which takes care of controlling the gas pedal.

So in a regular / default / factory-equipped car, you can't contol the gas pedal over can. (The Gas pedal is wired discrete to the engine ECU (and the gas pedal position is NOT send via any can bus).)

The can IDs/messages used in the code example are only for this test environment and the seperate/non-default can bus. So i hope nobody comes to the idea connecting his/her mbed to any of the car can busses!

 

Hope i could help you.. ?

Don't hesitate to ask if anything is unclear. (btw: I may need sone days to answer)

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Greetings,

Kevin.

 

 

 

 

 

 

Kevin Konradt
05 Jan 2010

( hm.. 'edit'  doesn't work..? )

There is a nice documentation to the basics of CAN from Vector Informatik GmbH

( Subchapter 2, CAN Transceiver starts with the description of the pysical layer. )

Fidias Dimitriou
10 Dec 2010

Hi kevin

i am working in a project for my final project in B(eng). which is a vehicle black box. I am going to take some readings from an OBDII but in the momment i can access on the common sensors. is there any way which allows me to get more!!

thanks in regard

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