Hold the horses. I think I have found a much easier approach then the evrouter or the gizmod (gizmo daemon) others have used to redirect the powermate to shell commands.
The evrouter and gizmod approaches require X to run. So why not use the xbindkeys tool that comes with X. You can use this tool to setup a action that’s associated with a button being pressed. This is done purely by entering the proper values in a config file. The link below shows how easy it is to setup a xbindkeys config file so a particular shell command (xterm in the example) is issued whenever a defined mouse button is pressed.
unix.stackexchange.com/questions … or-command
(check out the reference links on the bottom as they are great for udev knowledge)
Also with X it appears you will get Griffin Powermate device setup. I guess the Powermate is used allot on Linux boxes used as numerical controllers. See the support detail and what to look for on control output to X from a Powermate at the following link.
lists.x.org/archives/xorg/2009-April/045234.html
(you have to read up and down the thread to see all the info and the bug solution approach.)
The issue with the bad Powermate driver on the rpi2 remains. Any help on where that issue should be reported is most needed and appreciated.
The other problem also still remains, how do you install all of X on to Volumio 1.55 and not break it? We should make sure that all of X is included in Volumio 2 also.
The approach is great for ANY USB device that X knows about, and that list is huge. So just plug in an old USB mouse into your Volumio and run xev to see the X output protocol for each button or wheel turn of the device and then edit a config file and put in mpc and other shell commands using xbindkeys configuration method to control your Volumio node thru the USB mouse.
I can see folks taking apart a five button mouse with scroll wheels to get total control of their Volumio in the form factor they want and NO SOLDERING. Plus if you use an LED mouse the LED can be treated as a “the kernel is up and USB bus is a active” when the light is on and the hardware is shutdown when the mouse LED light is off.
Lets see, no soldering, complete volume and multiple button control, including a safe shutdown button, with an ON/OFF light for $20-30 by setting up a config file. Sounds good to me.
Why not include full X in Volumio 2 ?!?