Alarm systems have the tendency to become expensive if you go for the better systems out there. However, if you aren’t worried about having a complicated system, this noise maker would do the trick just as well. Plus with something such as this you could take it with you when you’re traveling and want to feel a little more comfortable while you sleep at night.
This door stopper could slip in front of the door, then when someone opens the door it activates the alarm. It has adjustable sensitivity and can be turned off entirely. Which means during the day it won’t be an issue when you don’t want the alarm on. To keep it powered you’ll need one 9V battery. In order to purchase the alarm it’ll cost you $14 from Gadget Brando.