How to use threeaxis as presence sensor

I am trying to use slight movements of the chair the threeaxis sensor is attached to to verify presence.

I cant seem to get this value to a variable or do anything meaningfull in rule machine with three axis data.

My idea is that if threeaxis changes, to set its values to variables, and then set a timer to turn off the computer, then watch for a change in threeaxis, and if there is any change, cancel the timer and start over. but I cant seen to do anything with it. Anyone have any advice?

Can you post a screenshot of the device page showing the capabilities and states?