It appears in System Profiler as:

Harmonix Drum Kit for PlayStation(R)3:

Version: 10.00
Bus Power (mA): 500
Speed: Up to 12 Mb/sec
Manufacturer: Licensed by Sony Computer Entertainment America
Product ID: 0x0210
Vendor ID: 0x12ba

Good start.

I installed GamePad Companion, and it detected the kit. I mapped different buttons to different keys, hit Start and switched to TextEdit. Hitting the drums gave me this:

2111111111111111111111111111444444333333333333332222222111111111111111111111222222222555555555555555555555555555555555555

Sweet. Each pad (and pedal) gave me a different key. The key repeat rate was really high, but it was working at least. So we end up with:

Button 1 = Blue (3)
Button 2 = Green (4)
Button 3 = Red (1)
Button 4 = Yellow (2)
Button 5 = Orange (Pedal)

As for the controller buttons on the kit (could come in useful!), the four symbol buttons all mapped to the same keys as the drum pads. The rest are:

Button 9 = Select
Button 10 = Start
Button 13 = PS Button

And finally, the d-pad maps to the “Hat Switch” element.

After this, I went looking for software to turn GamePad Companion’s HID input signals into MIDI signals. But after a few minutes I realized I didn’t need to.

I was already getting the drums to run my keyboard, and GarageBand has a feature to play the MIDI instruments with the keyboard. All I needed to do was map everything correctly and I should be good to go!

I opened GarageBand and set the default track to Drum Kits > Rock Kit. Then I turned on Musical Typing. You don’t get the whole musical keyboard with MT, just an 11-key section you can move up and down along a virtual 88-key keyboard. I moved the keyboard section down until the kick drum was available, then noted what keys where what:

A = kick
S,D = snares
F,G,H,J,K,L = toms
; = crash
and more…

I ended up choosing kick, snare, two toms and one cymbal, since the other cymbal I wanted was in a inactive area of the keyboard. I re-mapped the keys in GPC, switched back to GB and gave it a try. Success! Samples were triggered correctly, the fast key repeat rate didn’t cause any problems, and latency was basically nil.

Here’s a quick clip of Jake trying them out:

I *think* you can customize the keysets for Musical Typing, I’ll look into it more when I get more time. Customizing the MT keyboard layout would get you around the “can’t use samples from hidden areas of the full keyboard” problem. Once that’s figured out, this should make for a good RB-to-GB solution.

UPDATE 2007/12/8:
Several people have asked about the XBox 360 drum kit.

I don’t have access to Rock Band for 360, but I do have the Wireless Gaming Receiver to play with. I installed Colin Munro’s XBox 360 Controller Mac OS X Driver and got a controller synced up with it on my PowerBook.

(It simply would not work on my Power Mac G4, and looking around teh internets I see that the WGR can be pretty flakey. Hmm, Microsoft made something that often doesn’t work correctly… that’s odd.)

After getting the 360 controller successfully connected to the Mac, I opened GamePad Companion to see that it had found the controller. I mapped Buttons 1-4 (the A,B,X,Y buttons) to the A,S,D,F keys and then switched to GarageBand. The buttons successfully triggered the keypresses and played the drum kit samples.

I can’t say for sure that this means the drum kit will also work OK, but it is very promising. If anyone can try it out and leave a comment if it works, it would be much appreciated.

I’d also like to thank everyone who posted a link to this article:
Digg (this post)
Digg (video)
Gizmodo
XLR8YourMac.com
MacNN
Rock Band Forums (here, “Superchivo” demonstrates that this technique will also work with the guitar controller)
Create Digital Music