Write an article based on this "Glue the clothespin to the board. Manage excess wires with tape and hang the board. Attach the string to the piece of cardboard in the clothespin. Fasten the other end of the string to your door."
Remove your board from the wall. Your battery and buzzer should already be taped to it. Glue the clothespin so it is positioned somewhat close to the battery and buzzer. Follow the glue directions and allow the glue to dry completely before moving on. A clothespin is small enough that general purpose glue or hot glue should work to fasten it. For best results, you may want to use a sturdy glue or a wood glue. Wires sticking out in all directions can be a hazard. They can snag on objects or be easily pulled out. Damaged wires will deactivate your alarm. Tape your wires to the board to prevent them from snagging or being pulled out. Then re-hang the board on the wall. Tape a piece of string to the cardboard. Alternatively, use scissors to make a small hole in the cardboard and tie the string to the hole in the cardboard in a simple knot. Make sure the string is firmly attached to the cardboard. The door may be opened suddenly. If weakly fastened, the string may pull free while the cardboard remains. In this case, the alarm will not go off. Attach the string to the doorknob or tape it to a part of the door. Adjust the length of the string so that when the door opens, the string is pulled. When the cardboard pulls out, the alarm will go off. If your door is painted or made of a nice material, you may not want to tape the string to it. Some tape, when peeled away, can damage paint or wood.