I would add the caveat that if you suggest methods of control to the user(s), you want to be sure you cover as many of the edge cases as possible so you don't inadvertently suggest something that will either 1) cause the projector to behave unpredictably (as in the case where the controller closes and re-opens the shutter in the middle of a show and this triggers a start-up delay), or 2) create the perception of safety when not all conditions are actually "safe" (as in the case where the modulation inputs are left floating, which can produce output from some drivers). Either result reduces the safety of the projector.