signal related to the environmental stimulus to a processing unit determining whether the signal meets an alert threshold activating a detector of the portable x ray device if the signal meets the alert threshold producing a gray image through the activating step comparing the gray image produced through the activating step with a control gray image corresponding to a properly functioning detector application_number US 19702905 A description fig1 illustrates a simplified block diagram of a portable x ray imaging system 10 according to an embodiment of the present invention the x ray system 10 includes a portable x ray device 12 including a detector 14 having a sensor 16 mounted or otherwise secured thereto the detector 14 and the sensor 16 are in communication with a computer 18 having a central processing unit cpu 20 which is also in communication with a monitor 22 the components of the system 10 may be in communication with each other through wired or wireless connections the sensor 16 may be any type of sensing device that is configured to detect movement for example the sensor 16 may be an accelerometer if the x ray device 12 is tipped over dropped or struck the sensor 16 measures the physical.