Certain embodiments provide a rotational mechanism comprising a rotating part with an extension, configured to rotate about a first axis, a base comprising a sliding channel, wherein the rotating part is configured to rotate with respect to the base, and a stopping element comprising a stopping tab configured to interact with the sliding channel and further configured to interact with the extension to limit rotation of the rotating part. The rotating part is able to rotate the same amount in both the first direction and the second direction starting from a starting position and stopping at a stopping position, wherein, when reaching the stopping position by rotation in the first direction, the rotating part is restricted from further moving in the first direction, and wherein, when reaching the stopping position by rotation in the second direction, the rotating part is restricted from further moving in the second direction.