Arduino Nano v3.0 with NXT LineLeader

We are a group of students who are doing a project where we have to connect a LineLeader with our Arduino Nano v3.0. The connection is a I²C-Bus and our problem is that we can't figure out how to access the LineLeader with this Bus.

We connected it with the 5V pin, the ground pin, pin 6, pin 7 and we are using the wire.h library. One thing we are not sure of is how to assign pin 6 and 7 to SCL and SDA pins.

We found no example in the net of the LineLeader and our Arduino version, just different I²C-connected-Components and different Arduino's so we hope we can find some help in here.

we are not sure of is how to assign pin 6 and 7 to SCL and SDA

You don’t the I2C can only be on A4 & A5

What address are you using, you need the version that excludes the read / write bit. Can you post a link to the device you are trying to use.

That's our device:

http://www.mindsensors.com/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=111

OK we try pin 4 and 5 but how we know which cable of the I²C is SCL or SDA?

but how we know which cable of the I²C is SCL or SDA?

RTFM http://www.arduino.cc/en/Main/ArduinoBoardNano

ur problem is that we can't figure out how to access the LineLeader with this Bus.

and another FM for you to read http://www.mindsensors.com/index.php?module=documents&JAS_DocumentManager_op=viewDocument&JAS_Document_id=103

We already read this FM and we know we need the register-table in there to address the LineLeader. Problem is the downloadable Programs (Calibartion, Steering, ...) on NXT-Site are all for NXT-Software and we have to figure out how to do this with the arduino as well.

What we want to know is how we find out which of the four cables coming out of the LineLeader are for SCL, SDA, PowerSupply, ...

There is an open source project developed to control the NXT sensors with Arduino on launchpad.net.
I think that’s what you are looking for.
This project has created library of API’s (and several sample sketches) to read from NXT sensors and display in Arduino serial termina window.
Look for Project nxti2cdevice on launchpad.net
You can download a zip file of the library from there.

What we want to know is how we find out which of the four cables coming out of the LineLeader are for SCL, SDA, PowerSupply, …

It is a standard Lego brick. This shows you how to connect to a standard brick:-
http://www.instructables.com/id/Simple-interfacing-Lego-Mindstorms-NXT-to-Arduino-/

A bit of web searching reviles:-

Pin RB6 connects to the NXT yellow wire, RB4 is blue, Ground is both the black and red. … You also need to pull RB6 and RB4 to Vdd through 82K resistors.

From http://www.extremenxt.com/picnxt.html

look at following page, it shows how to connect the wires to Arduino. http://www.mindsensors.com/index.php?module=pagemaster&PAGE_user_op=view_page&PAGE_id=136