Researching this, I found a new resource I'm surprised I didn't hear about here. Haven't used it yet....
It's called Maple Virtual Midi Cable.
The driver is working! On another Xp install (for resolume).
Going to experiment now for a bit 
I have done all of the steps required to get the arduino to work as midi but I am still having problems. The arduino software recognizes when the piezo is touched but MIDI-OX and the midi drum software (CakeWalk Studio Instruments) I am trying to use it with dosen't respond to it. I am using the midi drumkit pde code. I don;t know if I have to change anything in that code? If anyone can help me with this problem or tell me a different way to do this please let me know as soon as you can. I am building a drum kit from piezos for my sound class and I am supossed to display it this weekend at our show. I need to get this working by then. Thanks
Is there a forum for this dedicated to windows, im sick of seeing mac
Most forums in the world, acidhax. If it doesn't name the OS explicitly then it will be Windows.
Looks like maybe three posts in this thread mention Mac OS at all, and none of them talk about a Mac-specific solution. As opposed to the three posts giving a solution that only works on a Windows PC.
Sorry for the mini-rant.
I'm puzzling over the same keyboard issues myself. I've got MIDI working fine, and I've got Arduino-to-Processing working fine. Haven't gotten MIDI out of Processing yet -- library problems to sort through still.
But on the hardware side, I've got a real tempting shape to work towards. And that's a one-octave (with octave key) keyboard designed specifically to work with monophonic instruments such as those in the Garritan libraries. The aim is a keyboard that doesn't attempt to emulate a piano, but instead allows expressive entry of a monophonic line -- and is small enough to stick in a laptop bag (and either battery or USB powered, to boot).
Mono means easier implementation of MIDI on the Arduino side. To make the keyboard properly expressive, however, would need to add the mod wheel CC (Garritan libraries use the mod wheel to control dynamics. Keyboard velocity is mapped only to attack).
And, of course, would help greatly if the keyboard was velocity-sensitive.
I've played one of those roll-up pianos. Unless someone can really improve the sensitivity and feel of piezo's I don't think my fingertips are up to hammering out 120 bars of music on them. The technique in the keyboards I've disassembled is using a lever-type key that hits two contacts in succession. Timing the difference between them becomes velocity. That seems simple enough to handle in Arduino; the question becomes more mechanical at that point.
Hi,
I just posted this related article http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1222793835 a couple days ago.
It seems to me that the most elegant solution for getting our Arduino to to MIDI over USB would be to just have a USBMIDIDriver. Fortunately for OSX users Apple provides a near complete driver. I have started modifying the driver but have hit a wall as far as my knowledge about how drivers work.
I am going to post the project on Google code this weekend and hopefully other more skilled people in the community can get involved and get this thing working.
Once it is finished all one should have to do is install the driver, then plug in your USB Arduino and start sending serial MIDI data.
I really hope we can get this working as it would benefit so many in the community.
Hallo evryone , Iam totally newbe , I have try to change to
HKR,,"ConfigData",1,11,00,3F,3F,10,27,00,00,88,13,00,00,C4,09,00,00,E2,04,00,00,71,02,00,00,38,41,00,00,9C,80,00,00,60,00,00,00,34,00,00,00,1A,00,00,00,0D,00,00,00,06,40,00,00,03,80,00,00,00,00,00,00,D0,80,00,00
but Iam still have problem with Roland Serial MIDI Driver Ver.3.2 for Windows XP, when Iam install in my laptop I cant choice for com 4 and this rolland doesnt work because just for com 3, in my case Iam using laptop just using port com 3 and com 4, and for arduino Iam using port com 4, so anybody have solution for my problem ? thanks
Has anyone tried combatdaves app?
second link down if google combatdave.
I couldn't get it going on XP but it may do the trick for OSX?
Thanks
@undervand:
would it be possible to post the processing code you mentioned in your post? i'm pretty much a noob in java/processing, but would really like to have my own-built arduino midi controller talk to my daw via usb.
I'm sure I'm not the first person to do create something like this, but here's a link to the windows application I wrote last night to help with MIDI testing on the Arduino.
It copies all note on, note off and controller data received over the selected serial port (at 38400 baud) to the default MIDI port you configured in Windows control panel. Use it with MidiYoke and you can redirect the stream into a VST synth.
I got tired of soldering up a DIN socket every time I wanted to test.
http://www.stephenhobley.com/blog/2010/02/15/serial-port-midi-relay/
Steve
For you Macies... I believe Kuk was onto something with the modification of the FTDI kext file (page one, sorry if this is too late to be helpful).
I just came across the FTDI technotes for MacOS... ftdichip TN_105
"Adding support for new FTDI Devices to Mac Serial Driver" Document Reference No.: FT_000107 v1.1
It looks like Kuk had the right idea: see section 3.2, it's pretty self-explanatory. My only addition is that at first baud-rate aliasing seems silly. Why not just set the baud rate you want? But it's because of the OS support which defines only specific baud rates which are standard amongst most RS232 devices (based on the standard-specified clock frequencies).
in Linux you get to use setserial to define an alias... which is handy for embedded devices...
You FTDI users are lucky their kext allows this... my PL2303 driver doesn't seem to support it...
I'm trying to do the opposite, I want a standard character device (like /dev/tty.midi) I can use to get raw midi data from my devices...
I haven't seen a link to this:
http://www.spikenzielabs.com/SpikenzieLabs/Serial_MIDI.html
in all the previous posts, so check this out. Might be interesting... I'll give it a try for communication between my sequencer and a arduino...
CU
Hi,
im working on a midi controller to control resolume as well.
http://www.student.tugraz.at/s.blamberger/faderboxv1.pde
it worked out quite well.
first is tried serial to midi software s2midi, but i foud out that it generates additional delay because its software that is executed in windows with not a high priority.
too the faders are moved strangely in the receiving software.
when i pull them up fast, they are moved up slowly like there was an maximal increment for the value to rise.
the Roland serial midi driver is much faster.
it worked for me without any bitrate hack.
what i am experiencing now is that the Roland driver works perfekt one time and seems to get stuck in some way the other time.
i have to program the arduino with another bitrate and set it back to 38400 later so get a midi signla in MIDIox.
is there a way to automatically reset the serial port in the code every sartup?
kool
//////EDIT//////
solved it myself:
added: these lines in void setup
serial.bergin(38400);
serial.end();
serial.bergin(38400);
everytimes it doesn't work
i push reset on the arduino and voila....it works.
kool
Thanks for this Thread and all researchers! My midi controller finally runs with hacked driver and midiyoke + serial midi app (Serial_MIDI) 
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1293990560/0#4