If your house/garage door has magnetic switch you can use this as Alarm Circuit.

Three magnetic switches: Normally open. G is the Garage door, SD is the Entrance door and GD is the internal door to the house.

There are two oscillator circuit and one schmitt trigger configured using the opamp (TL074 or equivalent)

Opening the GD or SD will also trigger a LED strip light (DL) to illuminate the garage for approximately 10 minutes.

Opening the SD door the oscillator of 2Hz will be activated and the buzzer will beep at 2 Hz and also the FL LEDs will flash at the same rate. Visual as well as audio tone is used for elderly people at home whose hearing is not good. They can see the flashing LEDs to know that the door is open.

Opening the (G) garage door will trigger a 10 Hz beeping and flashing lights will be at 10 Hz.

A push button switch can be used at contacts M1 / M2 to mute the audio alarm if the door is to be opened for a long time. Once all the doors are closed the circuit resets automatically.

DL and FL can be any 12V Superbright LED strip. No more than 4 or 5 LEDs

LED1, 2 and 3 are discrete Superbright (white) LED used as indicator on the board.

Variable Resistor 22 adjusts the intensity of FL LEDs. Variable Resistor 14 adjusts the intensity of Buzzer volume.

Hope this explains all features of the circuit.

Regards