This a simple but affective burglar alarm... It's messy right now but full proof! I will be coming out with a second and more cleaned up version of this alarm soon that will require only one or two more parts and be just as simple.
Step 1: Supplies (Not all supplies are pictured)
Electrical and or duct tape
An alarm or buzzer(found at a local RadioShack)
Two paper clips
A chip clip or clothes pin
Connecting wire with various lengths
A 9 volt batter
Something to hold the wire to your battery
And a card board square
Step 2: Building The Switch
Take the two paper clips and tape them on either side of the chip clip as shown. Attach a wire from the battery to one paper clip and a wire from buzzer to the other paper clip.
Step 3: Finishing Up
When you have the chip clip closed it will ring. Place the cardboard between the chip clip. Be creative on how you sound the alarm... When the cardboard is yanked from between the clip it will sound... I attached the cardboard to my door and tied a string to the clip so that when the door opens it will yank the clip and sound the alarm.
Step 4: Final Product
I know it's messy but remember I will clean it up and add some nifty tool and parts in on it to make it more effective in my 2nd model.