Abstract: A sprayer, comprising: a container, configured to contain liquid; a passage, comprising a first opening, a second opening, a resonator and a mesh, when the liquid is passed through the resonator, the liquid is emitted as a gas; a first optical sensor, configured to sense first optical data of at least portion of the mesh or at least portion of a surface of the container; and a processing circuit, configured to compute a foaming level of the mesh or of the surface according to the first optical data, and configured to determine whether the resonator should be turned off or not according to the foaming level. In another aspect, the processing circuit estimates a liquid level of the liquid but does not correspondingly turn off the resonator. By this way, the resonator may be turned on or turned off more properly and the liquid level may be more precisely estimated.

Abstract: A method of making micro-holes on a metal plate includes: (A) feeding a metal plate on a workbench forward to extend beyond a shearing edge; (B) locating a punching head at a first position, and keeping a working space between the punching head and the workbench; (C) exerting a shearing force towards the workbench by the punching head; (D) bending the metal plate by the shearing force, and forming a plurality of spot-shaped cavities arranged in a row on a second surface; (E) bearing a shearing force on the first surface of the metal plate to form a linear groove; (F) deforming the metal plate by the shearing force to cause the spot-shaped cavities arranged in a row to communicate with the linear groove to form micro-holes; (G) the punching head returning to the first position and moving a working distance to a second position; (H) feeding the metal plate again; (I) the punching head repeating the above steps at the second position; (J) the punching head returning to the second position and then moving back to

Abstract: An electro-magnetic wave filtering and impeding board is made of metal and includes a first side and a second side. The first side has multiple linear slots and the second side includes multiple concaved geometric holes which communicate with the linear slots. The electro-magnetic waves are impeded by the metallic material and weakened when passing through the linear slots and the geometric holes so as to impede the electro-magnetic waves.

Abstract: A method of making micro-holes on a metal plate includes: (A) feeding a metal plate on a workbench forward to extend beyond a shearing edge; (B) locating a punching head at a first position, and keeping a working space between the punching head and the workbench; (C) exerting a shearing force towards the workbench by the punching head; (D) bending the metal plate by the shearing force, and forming a plurality of spot-shaped cavities arranged in a row on a second surface; (E) bearing a shearing force on the first surface of the metal plate to form a linear groove; (F) deforming the metal plate by the shearing force to cause the spot-shaped cavities arranged in a row to communicate with the linear groove to form micro-holes; (G) the punching head returning to the first position and moving a working distance to a second position; (H) feeding the metal plate again; (I) the punching head repeating the above steps at the second position; (J) the punching head returning to the second position and then moving back to