A sensor device includes an irradiation unit that includes a light source and irradiates an object with light, an optical detection unit disposed on an optical path of light emitted from the irradiation unit and reflected at the object, at least one object sensor that detects presence of the object, and a controller that controls the light source based on output from the object sensor. The system can include a first processor configured to process and manage data for the computer-based system. This new process is an inexpensive and efficient process for the manufacture of these compounds. If the specified drift is exceeded, the system is able to reinitialize timing to reestablish the specified byte clock drift, and so continue the transfer of data from the interface device. The operation status detector detects a current operation status of the writing information generating device.