LabVIEW for LEGO MINDSTORMS and LabVIEW for Education

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Motor Multiplexer for NXT (MTRMX-Nx)

I think I have taken on more than I can handle. I need some help getting started with making a Custom block for the Mindsensor's RCX motor multiplexer. Details can be found here:

I have done the tutorial and still not sure what I need to do. How do I setup communication with the I2C unit? Once that is done how do I setup to send the appropriate byte codes to tell the unit which motor I want and what I would like it to do? (forward, reverse, brake, float).

Any help that would get me started would be greatly appreciated.

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Hi, Mike!

I don't have such a module available, but my approach would be the following: (Re)read pages 9 and 10 (and maybe everything else describing the other sensor types to understand some options) of the LEGO Mindstorms NXT HDK manual, available as PDF on the LEGO Mindstorms website ( Also have a look into Appendix 7 of that document - it's about the NXT ultrasonic sensor which uses the I2C protocol. (Don't be confused by some < "R" + 0x03 > in those manuals, it's something that gets inserted by the NXT firmware and can be ignored for the moment.)

After that have a (deep) look into the VI "Ultrasonic Sensor" in the NXT toolkit. Following the standard palette structure within LabVIEW, it can be found in NXTToolkit -> NXT Library -> Input. Also analyse the subVIs. You will find more or less all those things mentioned in the HDK document implemented by using the "NXT Input" property node (plus some additional logic).

Following all this there remains a lot of work to be done Smiley Wink but I think chances are good to end up successfully!!

Good luck


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once more me! I forgot to mention that the thread "I2C access in NXT-G" in this forum also might be a good starting point!



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