An LED-based light tube for use in a conventional fluorescent fixture includes a housing including a light transmitting portion, at least one electrical connector attached to the housing and configured for engagement with the conventional fluorescent fixture, at least one LED arranged to produce light in a direction toward the light transmitting portion, a sensor operable to detect a brightness level and output a signal corresponding to the detected brightness level, and a controller in electrical communication with the at least one electrical connector, operable to: compare the signal to a predetermined value corresponding to a desired brightness level and control an amount of power provided to the at least one LED in response to the signal to adjust the light produced by the at least one LED to achieve the desired brightness level.