Virtual reality is an immerging technology, which combines computer science, mechatronics, and ergonomics. One of the major applications of virtual reality is operator training simulation. In general, simple mechanical devices such as mouse, joystick, and keyboard that are commonly used in human-computer interface. However, these devices are not suitable for walkthrough simulation, which requires an interface that can fully reflect various biological inputs from a human body. This thesis focuses on walkthrough simulation and an overhead crane operator training simulator is used as an application. In the first part of this thesis, a novel interface device for locomotion in virtual environment is presented. The user*s feet can slide on the surface of this device by using the waist holder, which enables the user walkthrough in virtual environment. The position sensors are built-in the locomotion device so that the user does not have to wear any special equipment. In the second part of this thesis, a serial array-scanning device for the communication between host computer and locomotion device is presented.