How to Make a Door Alarm From a Kit

Connect the positive (+) wire on the battery pack to the corresponding connection on the alarm or buzzer. In some kits, this attachment will already be made.

Screw the trigger side of the magnetic switch (the side with the electrical connectors) onto the door jam you wish to arm. The edge of the switch should be flush with the door so that it still opens and closes easily.

Screw the second half of the magnetic switch onto the door itself. It should align with the first half so that they are in contact with each other when the door is closed. (The half attached to the door typically contains a magnet, which holds a contact switch in the half attached to the frame: when the door opens, the magnet moves away and the contact switch is released.)

Screw the second wire from the battery pack to the corresponding connector on the magnetic switch. Some alarms may use a remote or wireless system, in which case this step is not necessary.

Attach the second wire from the alarm to the appropriate connector on the magnetic switch. (As with Step 4, this may not be necessary in alarm kits with wireless components.)

Attach the alarm system to an appropriate location on the wall, using screws. In some cases, this will need to be near the door, but wireless systems can be placed anywhere within the range listed on the packaging.

Turn on the alarm and familiarize yourself with the activation procedures. In some cases, it may be as simple as turning on a switch. Other kits may involve entering a code or setting a clock. Understanding the activation sequence is important because otherwise you will not be able to use the door without activating the alarm.