Abstract: A pressure sensing device includes an elastic tube defming a chamber and an opening in one or each of two opposite ends thereof in communication with the chamber, and a pressure sensor component sealed in the opening in one or each end of the elastic tube for detecting a change in air pressure in the chamber when the elastic tube is compressed by an external pressure. The pressure sensing device can be used under a waterproof or dustproof environment, or embedded in a bed mattress or seat cushion and incorporated with a signal processor for detecting changes in the biophysical condition of the user, or embedded in a floor mat and incorporated with light and/or sound generating device for reminding your home or store that someone is coming in or going out. Thus, the pressure sensing device has the characteristics of simple structure, practical applicability and wide application range.

Abstract: A light control type key switch assembly includes multiple key switch units each including a key switch holder and a key switch mounted in the key switch holder, multiple light receivers respectively mounted around one respective key switch holder, and a light-emitting unit including a light source and a light guide facing toward the light source and neighbored to each key switch holder for guiding the emitted light from the light source along a light path toward each light receiver. When the key switch is not pressed, the plunger of the respective key switch is kept away from the light path, and thus no electrical signal will be generated. When the key switch is pressed, the plunger of the respective key switch enters the light path, causing an electrical signal output.