A vending machine includes a vend sensor for detecting a completion of a vend operation. The apparatus includes means for producing the native state, means for producing the emulated state, and means for comparing the native state and the emulated state. To realize this, the package is formed with an extra length of film extended adjacent to the main portion of the tube of the package. The controller locates the radial zone that defines the valve stem aperture from the scanned image of the wheel.