The tilt switch module KY-020 and the digital 13 interface come with LED to build a simple circuit, make the tilt reminder light. Use the LED of the digital 13 interface to connect the tilt switch sensor to the digital 3 interface. When the tilt switch sensor senses a key signal, the LED Lights up, otherwise it goes out. The tilt switch can output signals of different levels according to whether the module is tilted. There is a ball inside, so you can monitor the tilt. When the switch is tilted higher than the horizontal position, the switch is turned on, and when it is lower than the horizontal position, the switch is turned off.