@Umbertinho 

Hi,
If you want your camera to Alarm when it detects events or when Tapo S200B is pressed, please refer to the following instructions.
  1) Refer to the following instructions to enable the Alarm feature on a Tapo camera, and then the camera will alarm when it detects events.
       How to configure the Alarm feature for Tapo Cameras on the Tapo app
  2) Refer to the following instructions to add an automation entry to let the Tapo camera play a sound when the Tapo S200B is pressed.
      How to create Smart Action (Automation or Shortcut) on Tapo app
 

If you have other requests, please describe the usage scenarios in detail.

By the way, the Tapo C110 is a Tapo camera, not a magnetic sensor. 

Best Regards