Introduction: Door Alarm

About: I am just a guy who likes to make things!

This door alarm is a really cool way to know if some one has entered a/your room.

No more need to purchase a alarm!!! If someone opens the door when you're home, you will know


  1. Blue tape
  2. AA Battery
  3. AA Battery holder
  4. Buzzer
  5. Wire
  6. 2-inch strip of paper

Step 1: Mounting the Battery

First, Put the AA battery in its casing

Then, find a wall next to a door and tape the battery case about 1 centimeter away from the door.

Step 2: Attaching the Wire, and Mounting the Buzzer

First, twist wires on to the positive and negative sides of the casing (if there are no wires already there)

Second, tape the buzzer about one foot lower than the AA battery, and about 1 inch away from the wall, we will screw it in later

Step 3: Attaching the Wires and Taping Them Together

First, take the buzzers negative wire and and tape it to the AA battery cases negative wire, then take the buzzers positive wire and form an X shape, like in the picture (make sure a good amount of the buzzers positive wire is exposed).

Step 4: Attaching the Paper, and It's Wire

Take two one-inch pieces of tape and secure the strip of 2" paper. Bend the end so that it is at a 20˚ angle like in the picture

Step 5: Adding the Final Wire, Screwing in the Buzzer, and Final Adjustments

  1. Take some bendable wire and tape it to the AA battery case make sure you make it in a C shape, and that the end lands were the paper was bent.
  2. Take two screws and screw in the buzzer.
  3. Open the door and see if the bendable wires end (the one connected to the positive AA battery casing) lands on the buzzers open positive end. The result should be the buzzer going off.

Final Adjustments:

If the wire doesn't stay on the buzzers positive wire bend it a little or adjust the tape, if it still doesn't work repeat.