Hack and / - Wii Will Rock Linux

The final Rock Band instrument is also my favorite—the drums. Although you could argue, I suppose, that the microphone is the closest to a real instrument in the game, the drums feel the most real to me. The big question, of course, was whether the drums registered in Linux. Upon connecting the drums to my machine, I had hope from the dmesg output:

[  400.997524] usb 1-1: new full speed USB device 
    using uhci_hcd and address 7
[  401.059524] usb 1-1: configuration #1 chosen 
    from 1 choice
[  401.078667] input: Licensed by Nintendo of America  
    Harmonix Drum Controller for Nintendo Wii as
    /devices/pci0000:00/0000:00:1d.0/usb1/1-1/
↪1-1:1.0/input/input14
[  401.104320] input,hidraw0: USB HID v1.11 Gamepad 
    [Licensed by Nintendo of America  Harmonix Drum 
    Controller for Nintendo Wii] on usb-0000:00:1d.0-1

It turns out the drums show up as a joystick device, just like the guitar. I ran jstest (as with the guitar), pointed to the new joystick device, hit a few of the drum pads, and was able to see that they definitely generated button events. Specifically, I saw that blue was button 0, green was button 1, red was button 2, yellow was button 3, and the foot pedal was button 4.

Now, although I could presumably use the drums with Frets on Fire, or really any game that supported joysticks, unfortunately, I wasn't able to find a free game for Linux that specifically used the drums. Instead, I found something arguably better: a free Linux drum kit program called Hydrogen that lets you create your own drum tracks and can interface with the keyboard or a MIDI device. Hydrogen was packaged for my distribution, or alternatively, you can download and build it from the official site. Unfortunately, the Wii drum kit doesn't act as a MIDI device, and Hydrogen isn't set up to accept input from a joystick. Hydrogen does allow you to use keys on the keyboard to activate different parts of the drum kit, so I had to figure out a way to map the joystick buttons to key events. Lucky for me, such an application already exists called joy2key. joy2key is a pretty basic program. You run the program on the command line and tell it which joystick to use and which keys to map to particular joystick buttons. Then, you can click on the application to bind it to, and it will send all joystick events to that particular window.

joy2key also already was packaged by my distribution, and after it installed, I simply had to choose to which keys to bind buttons. The first five drum types are activated in Hydrogen by the Z, S, X, C and D keys, respectively. So, first I launched Hydrogen, and then in a terminal, I typed:

joy2key -X -buttons d c s x z -dev /dev/input/js0 
 ↪-thresh 0 0 0 0 0 0 0 0 0 0 0 0

In addition to the -buttons option, the -X option tells joy2key to send X events. The -dev option points it to your joystick device, and the -thresh option sets the low and high thresholds to trigger events for each button. If you don't specify -thresh, joy2key prompts you to set the values each time you run it, and as these buttons are either on or off, I just set them to zero. After you run this command, your mouse icon should turn into a cross. Click on the Hydrogen window, and then joy2key will start sending events to Hydrogen.

The order of drum sounds and how they correspond to keys is set in the Hydrogen pattern editor (Figure 5). There are any number of different ways to arrange the sounds and button mappings, but probably the easiest order to keep straight sets the pattern editor as though you played across the Wii drum kit starting at the foot pedal. By default, this probably won't be set correctly to suit the joy2key settings, so click a particular drum sound to highlight it, and then press the up/down arrows on the top of that column to rearrange its order. On the bottom, put Kick, then a Snare, then a Hi Hat (like Open HH), then a Tom, then a Cymbal (Crash). Once you have arranged these sounds, hit some of the drum pads on the drum kit, and you should hear their corresponding sounds on your computer. Go ahead, play a drum solo or two to get accustomed to the current pattern.

Figure 5. Hydrogen with the Pattern Editor Window Selected

Hydrogen is a complicated enough program to warrant its own article, but here are some of the many things you can do now that the Wii drum set works with it. For one, Hydrogen includes a number of different drum set samples from which you can choose, and you even can create your own, so you can experiment with a lot of different sounds for your drums. In addition, you also can use your drum set when recording different beat patterns. Finally, if you want, you could just hook up your computer to a loud set of speakers and start playing. Hydrogen includes a mixer for each sound, so you can adjust the relative volumes.

Well, if you weren't already tempted to buy a set of Rock Band instruments just for your Wii, now you have another excuse...er, reason...why you need them. It's a testament to how far Linux has progressed that you can get random devices like these working on your computer with minimal effort. As for me, I'm going to switch up the drum patterns in Hydrogen so that they feature more cowbell.