How does OpOO mobile phone judge whether the rented house is equipped with monitoring?

You can't use your mobile phone to check whether the room is monitored.

This method can only be used to check cameras with infrared function.

Just turn off all the lights in the room, then turn on the camera function on your mobile phone and shoot with your head facing the surroundings. If there is a camera, there will be a light spot in the shooting process, and that is the camera.

After turning on the application encryption function, go to the settings of mobile phone-Security-Application Encryption, select the software to hide-turn on the switches of "Start password verification" and "Hide desktop icon".

Measure it with the lens of a smartphone. Specifically, the method is like this, because people can't see the hidden camera, so first you have to close the curtains, turn off all the lights, then turn on the camera function of the mobile phone and shoot around the room with the mobile phone, slowly. If you put it in a place and find a red dot flashing in the lens of your mobile phone, then there may be a camera hidden in this place.