By thinknut.blogspot.com

How to Make a Door Alarm ???

It can be very annoying when your siblings enter your bedroom without permission. If they keep on going inside, despite your threats and pleas, make a door alarm!

You Will Need :

• Buzzer
• Battery 
• Wires
• Clothes Pin

Process :

Place the battery and buzzer on the wood as shown in the picture. Tape them down with electrical tape.

Wrap the ends of the clothes pin with bare, non-insulated wire.

Connect one of the free ends of wire around the clothes pin to a wire coming from the battery.

Connect the wire around the clothes pin to the buzzer.

Connect the remaining free wire from the battery to the buzzer.

Test the switch by opening and closing the clothes pin. When the clothes pin is closed, the buzzer should turn on. If not, check the wiring again.

Place a piece of cardboard or other insulative material in the clothes pin to separate the wires so that the buzzer does not go off anymore when it closes.

Glue the clothes pin to the wood, as seen in the picture.

Attach the string to the piece of cardboard between the clothes pin things.

Attach the other end of the string to your door. Place the alarm so that the string is taut between the alarm and the door. When the door opens, the string should pull the cardboard out, setting off the alarm.