HiLetgo 10pcs TTP223B Switch Module Digital Touch Sensor Capacitive Touch for Arduino This is the "momentary" variety of the touch sensor - touch and it turns on, release and it turns off. Positive and negative can be used as a touch surface,can replace the traditional touch button. Four M2 screws positioning holes for easy installation.Module can be installed in such as surface plastic, glass of non-metallic materials. In addition to the thin paper ( non-metallic ) covering the surface of the module , as long as the correct location of the touch , you can make hidden in the walls, desktops and other parts of buttons. The module is based on a touch-sensing IC (TTP223B) capacitive touch switch module. In the normal state, the module output low, low power consumption; When a finger touches the corresponding position, the module output high, if not touched for 12 seconds, switch to low-power mode.