A waterproof housing for a digital device includes front and rear bulkhead members for sealably holding a digital device having a touch screen. The touch screen is positioned to be viewed through a transparent surface of the rear bulkhead, which includes an aperture through which an actuator is sealably positioned. The actuator includes a shaft extending through the aperture, a control member connected to an outer end of the shaft, a stop member affixed to the control member for contacting the housing or engaging the recess, an extension member connected to an inner end of the shaft, a first probe affixed to the extension member near the shaft, and a second probe affixed to the extension member at an off-center position relative to a center axis defined by the shaft. The actuator is configured to selectively operate the first and second probes to execute touch motions on the touch screen. Other aspects of the invention include a lens mount system having a threaded aperture provided on the waterproof housing, a lens arrangement including an optical lens coupled to a threaded collar, and a positioning assembly for fixedly locating the lens arrangement to the housing at a predetermined rotational engagement position of the threaded collar to the threaded aperture. The positioning assembly includes a releasable locking pin that is located in the housing adjacent to the threaded aperture, and a recess in a mounting surface of the lens arrangement for receiving a locking end of the pin when the lens arrangement and the housing are positioned at the predetermined engagement position. At this position, an optical feature of the lens arrangement is located at a desired predetermined distance from an optical plane of a camera of a digital device positioned within the housing.