The Griffin Powermate knob is a nice input device, so it would be convenient to get data from it in a simple way to use for various purposes. These kexts let you get data from the Knob using Apple's HID (Human Interface Device) api, to do with as you wish.
Update: I got an email saying that these kexts let you use a Griffin Powermate Knob as a controller for max/msp through the HID support built into max/msp.
Update: I added an Intel version of the driver.
Intel Version, all 3 Kexts in 1:
Get The Kext
PPC Version, 3 Kexts:
Get The Kexts
Links:
Knobs, from the source.
HID Example Code from Apple.
HID Explorer, a nice HID debugging tool from Apple.
Contents of ReadMe(Intel):
This driver allows 3 versions of the Griffin Powermate to work through HID on OS X.
Version 265, 2 LED's on bottom, with no drivers installed moving the knob moves the mouse
left-right. This is fine, but as well as sending data to your app through HID, it also moves
the mouse as you rotate. Install this kext.
Version 801 or 1024, has 1 or 2 LED's on bottom, with no drivers it does not move the mouse
and can be used through HID but the rotation data shows up oddly (only changes in rotational
speed come through, so constant speed rotations show up as no rotation). This is because the
knob rotation axis shows up as absolute instead of relative, making a number of things in the
HID implementation confused. So install this kext to avoid this problem (just changes the
knob's rotation axis to relative from absolute).
You can check the version using the HID Explorer among other ways, see link at bottom. (Or
you can just try these and see if they work)
To use the powermate through HID, you must NOT have the griffin driver installed. I kinda
forget where this is installed, probably /System/Library/Extensions. It is called
"PowerMate.kext", so you can search for it.
To load the kernel extension, go the KnobKext folder. To make sure the permissions are
correct on the kext, run ./setupPermissions in that directory. Then, to load the kext, type
./load. You will see some info, hopefully the load will succeed. Unplug and replug the knob
for the driver to take effect. You will have to be an administrator to run the scripts since
only an administrator can load kernel extensions (they will ask for your password).
The driver will stay loaded until you restart. You can also put it in
/System/Library/Extensions, but you might as well try it out this way for a while first to
make sure it's ok.
Disclaimer: This software comes with no warranties of any kind. Though it works for me, it
will probably destroy you and all the data you have and even some that you don't. Though I
really like the Griffin knobs and made these kexts to use them programmatically from within my
projects, i have no affiliation with Griffin Technology whatsoever.
Oh yeah, to see what's going on with HID the "HID Explorer" sample project from apple is
useful... (http://developer.apple.com/samplecode/HID_Explorer/HID_Explorer.html)
Contents of ReadMe(PPC):
These kext's are designed to allow you to get data from the Griffin Powermate through
HID on OS X.
Check which version of the knob you have:
-Old Version (265) has 2 led's on the bottom. (You can tell you have this one if, without the
griffen driver, moving the knob moves the mouse) -New Version (801?) has 1 or 2 led's on the
bottom. If yours is newish and has 2 led's, check version using the IORegistryExplorer, or
HID Explorer (see end of document for url).
To use the powermate through HID, you must NOT have the griffin driver installed. I kinda
forget where this is installed, probably /System/Library/Extensions. It is called
"PowerMate.kext", so you can search for it.
OLD: If you have the old version, without the griffin driver it shows up as a mouse to the HID
system. This is fine, but as well as sending data to your app through HID, it also moves the
mouse as you rotate. Install the kext for the older knob to prevent it from showing up as a
mouse.
NEW: If you have the new version, it no longer shows up as a mouse. However, the knob
rotation axis shows up as absolute instead of relative, making a number of things in the HID
implementation confused. So install the kext for the new knob to avoid this problem (just
changes the knob's rotation axis to relative from absolute).
BOTH: To load the kernel extension, go to the appropriate directory for your knob and OS. To
make sure the permissions are correct on the kext, run ./setupPermissions in that directory.
Then, to load the kext, type ./load. You will see some info, hopefully the load will succeed.
Unplug and replug the knob for the driver to take effect. You will have to be an
administrator to run the scripts since only an administrator can load kernel extensions.
The driver will stay loaded until you restart. You can also put it in
/System/Library/Extensions, but you might as well try it out this way for a while first to
make sure it's ok.
Disclaimer: This software comes with no warranties of any kind. Though it works for me, it
will probably destroy you and all the data you have and even some that you don't. Though I
really like the Griffin knobs and made these kexts to use them programmatically from within my
projects, i have no affiliation with Griffin Technology whatsoever.
Oh yeah, to see what's going on with HID the "HID Explorer" sample project from apple is
useful... (http://developer.apple.com/samplecode/HID_Explorer/HID_Explorer.html)
