Saturday, February 6, 2010

Using Wesen's MIDIDuino library on a Mac

I ran into a few problems using Ruin & Wesen's excellent MIDIDuino library on my Mac - here are three things to know:

Thing 1 - Incompatibility with Recent Arduino IDEs

Because of some changes in the gcc bundled with recent Arduino IDEs, you need to use an older IDE (verson 0013 is known to work) with the MIDIDuino library. I'm sure that Wesen will eventually fix that, but for now, get 0013 and install it on your Mac (this advice applies if you're running it on a PC as well).

Thing 2 - Arduino 0013 and 64-bit Snow Leopard

If you're running Snow Leopard, depending on which model of Mac you have, you may be running in 64-bit mode, and if so, you'll get the following error when you try to launch Arduino 0013:

So search engines can find this, the text in the dialog is:

Cannot launch Java application

Uncaught exception in main method:
Resources/Java/librxtxSerial.jnilib:no suitable image found.
Did find: /Applications/arduino-0013/Arduino/
no matching architecture in universal wrapper

To fix this, set Arduino-0013 to run in 32-bit mode. First, find the Arduino app (if it's in your dock, you can Crtl-click, then choose Options->Show in Finder. Single-click the app, then choose Get Info. In the inspector that appears, click "Open in 32-bit Mode" and dismiss the insepctor.

Thing 3 - Arduino preferences.txt problems

If you've run more recent versions of the Arduino IDE, you may have an Arduino preferences file that the Arduino 0013 can't read. You'll get this error:

Cannot launch Java application

Uncaught exception in main method:
java.ang.NumberFormatException: null

The simplest thing is to delete the file, or rename it. Of course, if you need to also run the newer Arduino IDE from time to time, you'll need to perform this every time you switch back. This is left as an exercise for the reader. :-)

To find the preferences file, choose "Preferences" from the File menu, and look at the bottom for "More preferences can be edited directly in the file".

Oh, and this advice about the preferences file also applies to PC users.

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