Do you need a door alarm? Do you not have the money to buy that door alarm? You can make a door alarm for your home with common things that may already be lurking around your house.
First, decide what the door alarm purpose is going to be. Is it just to warn you when your kids are going to burst in? Is it for the knowledge of when your pet is not where it should be? You may even wish to have an intruder door alarm.
For your door alarm sound you will need to find a noise maker. Perhaps you have an old decorative bell that is just sitting on your bookshelf. That will work just fine. If you cannot find anything else, then procure a spoon and sturdy glass or metal cup.
A door alarm clapper made from a cup and spoon is made as follows: The cup must be installed against a hard surface the spoon, and must have a small board or metal bracket attached to the same surface. This will allow the spoon to rest in the center of the cup without touching the cup. The tripping wire or string can be tied to the spoon to shake the spoon against the sides of the cup. This shaking will give off a sound as a bell.
The following tips will help you install your door alarm. Make sure you have some room above the door jamb on the top of the door. Mount the clapper or noise making device in a desired location. This may be done with an eye hook into the wall just below the ceiling. Some ceilings may be close enough to do that. If it is more than a foot away you should probably consider not using the ceiling option.
Securely mount the noise making device to the desired location. Next install the trip wire or string for your door alarm. Mount the string or wire to the top of door making sure enough slack in the rope or wire as to not interfere with the opening of the door. Your door alarm trip wire can be mounted with an eye hook. For temporary door alarms duct tape works great.
Finally, fasten the end of your tripping device to the clapper on your noisemaker. Once again it must be tight enough to pull the clapper and make noise, but not so tight that it keeps your door from functioning.