How to Make a Compact Alarm System

Place a battery pack on a work surface. Cut 3 10-inch lengths of electrical wire from the electrical wire spool with a scissors.

Strip ½ inch of insulation from both ends of all of the wires with a wire stripper.

Heat up a soldering iron for 5 minutes. Solder an end of one of the wires to the positive contact (labeled "+") on the battery pack. Solder an end of another wire to the negative contact (labeled "-") on the battery pack. Let the solder cool for a minute before continuing.

Place a DC-powered doorbell buzzer on the work surface. Solder the free end of one of the wires from the positive contact on the battery pack to the positive contact (labeled "+") on the buzzer. Solder an end of the remaining wire to the negative contact (labeled "-") on the buzzer. Let the solder cool for a minute before continuing. Unplug the soldering iron.

Use wire strippers to strip an additional 4 inches of insulation off the free end of the wire soldered to the negative contact on the battery pack and the wire soldered to the negative contact on the buzzer.

Hold a clothespin in one hand with the closed end facing up. Press in on the bottom two ends of the clothespin to force the closed end open. Wrap one of the ends of the two wires around each of one of the two now-opened ends of the clothespin so that they will touch each other when you release the ends.

Press the bottom two ends of the clothespin together again. Open a window. Place the bottom two ends of the clothespin on the windowsill and close the window on the clothespin; the now-opened ends of the clothespin are facing you. Lock the top lever on the window as an added safety measure.

Place the battery pack and buzzer on the floor beneath the windowsill. Insert batteries into the battery pack. The buzzer of your compact alarm system will now sound an alarm if the window is forced opened.