How to notify the user when the charger is disconnected from the laptop?

Question

linux

Good day
Unfortunately, the contact between the charger and the laptop on lubuntu20 periodically disappears and it is not possible to solve this problem with hardware repair or replacement.
The contact disappears, and the laptop runs on battery, which depletes the battery life. In addition, sometimes the work started or writing another question with the tag kotlin suddenly ends.
Is there a way to use a script to make an audible or more noticeable visual (lxqt shows a small plus while charging) signal when disconnected from the power supply?
Where to look for rules for powermanager?
Maybe there are ready-made applications for solving the problem?

Answer 1

Set the screen brightness to decrease when running on battery power.

Answer 2

Repair or replace the connector before it burns out completely, and do not engage in unnecessary.