A method is provided for constructing a platform for use in a sensor in a microfluidic device. The marking pen further includes a high porosity fiber channel writing nib whose ink flow channels are of a sufficient size to allow the phosphor particles suspended in the ink to flow by capillary transport through these channels onto an ink receiving substrate material. Therefore, the user can modify a file feature parameter in the original file type configuration file, and when a file feature parameter of a file of a certain type is changed or a file of a new type appears, the user can update a file feature parameter in the state machine in time to identify the changed file or the file of the new type.