Disclosed is an augmented reality-based three-dimensional menu system using manual operation tools. The humidity sensor of the laundry drying machine is installed on the front panel having a relatively high strength so as to support the total weight of a drying tub and laundry contained in the drying tub, thereby maintaining the stable installation of the humidity sensor for a long period of time and reducing the generation of errors of the humidity sensor. Each of the plurality of elements includes a photodetector for detecting light that produces a signal corresponding to light incident upon the photodetector, and a processor for producing a forward discrete wavelet transform of the signal. The at least one flow channel is in fluid communication with a region external to the microelectronic substrate.