A camera apparatus capable of tracking a target object based on motion of a camera sensed by a motion sensor and a method for tracking an object in the camera apparatus are provided. Structure consisting of multiple photoresist layers is first formed on the substrate, then patterned using adequate exposure energy and development condition so that the bottom photoresist layer is not developed while the first under-cut resist groove is formed on top of the bottom photoresist layer. A first semiconductor device is attached on top of the lead frame portions as a flip chip, while a second semiconductor device is attached to a bottom side of said paddle portion and is in electrical contact with said the first semiconductor device. Since the heating filament does not directly touch the patient’s blood, the outer surface may be made smooth so as to prevent inducement of blood clots. The locking mechanism is formed by a downturned locking flange positioned between the fingers in one of the tray panels and extending downwardly into and, preferably through, openings located in the overlapped margin of the other tray panel. That parameter optimizes response to light from the retroreflector, while minimizing response to light reflected by other objects.