The Clock can be used for turning lights on and off automatically. It functions as an alarm in relation to the day-night cycle. The clock's face is divided into 48 "ticks" and each tick represents 30 seconds in real-time. The green tick shows the start time for the signal while the red tick represents the end time, and the black tick represents the current in-game time. The clock shows the activation period with a white line that connects the green and red ticks in a clockwise manner. While the black tick lies within the white line, the Clock will emit a continuous signal, similar to a lever.
The two buttons on the bottom of the clock always change the position(s) of the ticks in a clockwise direction; the left button setting the green tick, and the right button setting the red tick. Multiple clocks put together can be used to create an actual clock, though this is rarely seen.