The beep sound is an “alarm” of some sort. Most likely, some device that has a low or bad battery and it is simply letting you know that it needs to be serviced. As a long time service technician and customer service representative, I have handled many calls about this type of issue.

Why do I hear a random beep in my house?

Reasons a smoke detector makes a continuous beeping noise include: The smoke detector's battery has not been installed properly or may be loose. The sensing chamber of the smoke detector may be dirty. Environmental factors like humidity or heat may set off an alarm.

What causes beeping?

All it takes to make a beep is a common electric circuit that produces a square wave, a simple type of signal that jumps back and forth between two levels, and a speaker to amplify it.