At work we are currently using what I suspect is a burglar alarm as a door buzzer. It's inappropriately loud to have buzzing the entire time the door is ajar (from barely open onward), as we're a motel and it's frankly obnoxious. However in order to hear people come in from the basement, it's what the folks in charge decided to use. I would very much like to create a monostable circuit so it buzzes for a small amount of time then turns off until the door is shut again, re-arming the buzzer. The buzzer works using a momentary switch that is pressed when the door is shut and released when the door is open. This switch is connected to what looks like a transformer core, and the device also plugs into our AC outlet.
I have looked at circuits online, but even using a few simulators I was unable to produce results like I wanted. Can I have some advice? I'm new to electrical engineering.
