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interoperability - Problem with SerialIO package and Lego NXT


I'm following a guide from The Mathematica Journal that describes how to use Mathematica with the Lego Mindstorms NXT but have some trouble getting started and got stuck with the SerialIO package.


I use Mac OSX and I have installed the package to:



/Applications/Mathematica.app/AddOns/ExtraPackages/SerialIO/

The command Needs["SerialIO`"] gives me the following error message:


LinkOpen::linke: Could not find MathLink executable.

And trying


SetDirectory[FileNameJoin[{$InstallationDirectory, "AddOns", "ExtraPackages", "SerialIO", $SystemID}]];

Does not help either, it gives:


SetDirectory::cdir: Cannot set current directory to /Applications/Mathematica.app/AddOns/ExtraPackages/SerialIO/MacOSX-x86-64.


There seem to be some problem with the alias/symbolic link in the SerialIO folder. By default they pointed to an absolute directory on the machine that this library was built on:


MacOSX-x86-64 -> /Files/schofield/Packages/SerialIO/Build/Mac/build/Deployment/Package/SerialIO/MacOSX

I tried deleting the alias and creating a symbolic link in the terminal:


# ln -s MacOSX MacOSX-x86-64

Running the SetDirectory command again result in... no result, so I guess thats good. The commands seem to have been loaded as when typing Serial it want to autocomplete to SerialOpen etc.


However, using the command mybrick = SerialOpen["NXT"] does not put the NXT in connected mode (<> on NXT display). Does anyone else got it to work?



Answer




I finally got it to work with a little help of this and a git hub repo of the SerialIO package.


The problem was the line $Link = Install["SerialIO"] in init.m. This seem to only be valid on Windows so I changed this to the suggested $Link = Install["SerialIO", LinkProtocol->"Pipes"] and it now works.


Also, the mybrick = SerialOpen["/dev/tty.NXT"] had to include the full path to the serial port.


OSX aliases did not work either. I had to create a symbolic link alternatively create a "MacOSX-x86-64" folder with the SerialIO application to make it work.


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