The python evdev module can find the device and print the button events:

https://gist.github.com/jburgess777/a6dd67e7fbaaee82c856

$ sudo ./getButton.py
device /dev/input/event17, name “AB Shutter 3”, phys “00:1b:10:00:2a:ec”
key event at 1456268812.859839, 115 (KEY_VOLUMEUP), down
key event at 1456268812.860800, 115 (KEY_VOLUMEUP), up
key event at 1456268813.736843, 28 (KEY_ENTER), down
key event at 1456268813.909845, 28 (KEY_ENTER), up

The grab() call should prevent the key presses from being seen by anything else