A proximity sensor includes first and second sensors disposed on a sensor body adjacent to one another. The first sensor is one of an emitter and a receiver. The second sensor is the other one of an emitter and a receiver. A third sensor is disposed adjacent the second sensor opposite the first sensor. The third sensor is an emitter if the first sensor is an emitter or a receiver if the first sensor is a receiver. Each sensor is positioned at an angle with respect to the other two sensors. Each sensor has a respective field of view. A first field of view intersects a second field of view defining a first volume that detects a floor surface within a first threshold distance. The second field of view intersects a third field of view defining a second volume that detects a floor surface within a second threshold distance.