Abstract: An animal door unit comprising a front panel, a left rear panel, a left guide, a right rear panel, and a right guide, wherein the front panel comprises an entrance; and a door plate having a plurality of guide holes, the door plate configurable in a retracted state and an open state, wherein, in the retracted state, the door plate traverses the entrance, and wherein, in the open state, the door plate does not traverse the entrance. The animal door unit may include a motor disposed within a module case; and a sprocket in rotational communication with the motor, wherein the sprocket interfaces with the plurality of guide holes, such rotational movement of the sprocket inducing linear movement in the door plate.