Modify the signaling circuit to make a delay using a capacitor?

Question

Electronics

Good time of the day. In general, I have a simple signaling scheme.
I have a question: how to make the LED work for a certain number of seconds when the security loop is opened (I plan to set this delay with a variable capacitor) after that the LED should turn off (although the security loop is still open) after the security loop is closed, the cycle should will repeat.

I don't understand how to do it.

Answer 1

Google like this: https://www.google.com/search?q=waiting+multivibrator
https://vpayaem.ru/information18.html (this is all put in place of the LED)

Answer 2

I have a simple signaling circuit.

Is she in the picture?
Currently, this is most easily done on a microcontroller. There will be less worries about the required capacity and its leakage, it will be easier to add new features.
If it is desirable to remain in the "analog" circuitry, then I would think about the circuit for the "555 timer" (1-2 pieces). There, the control of the loop will also be the time delay (which depends little on the supply voltage and temperature).