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Thanks to those who helped me with my previous question. I will help others too where I can. In the meantime I have a general question whether anyone has had success connecting Mathematica to the LeapMotionTM device on a Mac? If so, please could you show me how you did this? I have followed instructions on the following page but got Java errors, and I use OSX not Windows:

http://community.wolfram.com/groups/-/m/t/90931

The only modifications I made to the instruction code was to change the directory symbols from "\\" to "/", though I have tried both formats.

Needs["JLink`"];

ReinstallJava[CommandLine -> "java", JVMArguments -> 
   "-Djava.library.path=[/Users/myname/Desktop/LeapDeveloperKit/
LeapSDK]"]; (*etc...*)

I have programmed the LeapMotion in Processing but would prefer to prototype some ideas in Mathematica as I can understand the math better with that before rewriting in Processing. Thanks.

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  • $\begingroup$ It would probably be helpful to post up those java errors. $\endgroup$ – Gordon Coale Oct 10 '14 at 15:24
  • $\begingroup$ Java::excptn: A Java exception occurred: java.lang.NoClassDefFoundError: Could not initialize class com.leapmotion.leap.LeapJNI at com.leapmotion.leap.Controller.<init> (Controller.java:39) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) at java.lang.reflect.Constructor.newInstance(Unknown Source).JavaNew::fail: "Error calling constructor for class "com.leapmotion.leap.Controller" $\endgroup$ – awyr_agored Oct 10 '14 at 16:00
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I have spent a little time accessing the methods of the Java linker file for LeapMotion with Mathematica based on the work of others:

http://community.wolfram.com/groups/-/m/t/90931

Following their instruction, it is possible to access methods using Methods[] which returns a list of classes and methods. It is possible to follow the inheritance using this:

controller = JavaNew["com.leapmotion.leap.Controller"]
Methods[controller]

Code posted by Jari Kirma on the Wolfram Community site (link above) for creating methods to access finger position vectors:

getFrameData = 
  Module[{getFrame, getFingerList, getVector, makeRule, fun}, 
  ... (* etc *)
]

I have modified the code that was posted by Jari Kirma on the Wolfram Community site to illustrate the finger tips alongside their vector positions using Grid[], as well as a model of the LeapMotionTM on the desk:

Grid[{{
Dynamic[{((tipPosition /. #) & /@ (fingers /. getFrameData[controller])) // MatrixForm,
 Graphics3D[{
  (*Display model of LeapMotion on the desk*)
  Gray, Cuboid[{-25, -13, -17}, {25, 13, 17}],

  (*model finger tips*)
  Red, Sphere[{1, -1, 1} #[[{1, 3, 2}]], 15]} & /@ ((tipPosition /. #) & /@ (fingers /. getFrameData[controller])),
     AxesLabel -> Automatic, PlotRange -> {{-200, 200}, {-200, 200}, {0, 400}}]}, 
UpdateInterval -> 0.05]
}}, 
Frame -> All]

enter image description here

Decreasing the UpdateInterval value to less than 0.05 did not seem to speed up the graphics frame rate. Could this be a bottle neck in the device? Also, I have not used the AxesLabel option correctly as it does not appear on the 3D graphic, unless this is not an option for Graphics3D[]?

Also, please correct any of the above such as syntax conventions if possible.

Regards

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I solved the connection problem I was having by adding InstallJava to the code written on the afore mentioned web site. I am not sure why ReinstallJava did not work on its own without having to use InstallJava too.

Run this code first (straight out of the Wolfram website):

Needs["JLink`"];
ReinstallJava[CommandLine -> "java", 
   JVMArguments -> 
   "-Djava.library.path=[/Users/.../LeapDeveloperKit/LeapSDK/]"];
AddToClassPath["/Users/.../LeapSDK/lib"];

This is the part that's a little different:

InstallJava[]; (* does not work if this is not included *)
controller = JavaNew["com.leapmotion.leap.Controller"];
controller@isConnected[] (* test to see if LeapMotion is tied into Mathematica *)
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  • $\begingroup$ Sure, people who search for "mathematica LeapMotion" might end up here so feel free to add some measurements/code to your answer :) $\endgroup$ – C. E. Oct 11 '14 at 18:31

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