[MinnowBoard] Shutdown Without Keyboard or Mouse?

[Duane A. Damiano]

I would like to use a Minnow Board Max (MBM) to display the video from a 
USB camera.  It doesn't need to do anything else and it will not be 
connected to any network.

I have already figured out how to auto-login and auto-start a program 
(cheese) to display the video.  However, I have not yet figured out a 
way to properly power down the MBM.

Normally, the user would power down by clicking the appropriate menu 
items in the GUI or by running a command like "halt" or "shutdown -h 
now" in a command window.  But in this case, the user will not have a 
keyboard or a mouse.  Can anyone think of a simple way to implement a 
graceful shutdown, without just turning off the power?

I thought about connecting a button or switch to one of the GPIO pins 
and watching it with a script.  When the pin goes low, I could run a 
shutdown command.  But, the standard Debian kernel for the MBM does not 
recognize the GPIO pins.  (It doesn't create /sys/class/gpio and 
compiling a new kernel is beyond my comfort level.)

Any ideas for how to do this.  Or, is there some other hardware that 
would be better than the MBM for this task?

Duane