COVID-19 Notice: Our technicians are equipped with masks and gloves complying with health and safety regulations.

Door Alarm Systems: What Are They and How They Work


People often think of a door alarm as a simple device that makes noise. Only a few knew they were intricate blends of science and technology that keep our homes safe 24/7. Want to find out how they work and what makes them tick? Join us in this quest to learn about the complex science behind door alarm systems. Understand how they work and gain a new appreciation for these home security heroes in this blog. Let us start.

What Are Door Alarm Systems?

Door alarm systems are security devices for unwelcome entry, mostly through doors. Think of them like a watchful guard at your front door. Like a doorman would tell you if someone you do not know tries to get in, a door alarm sounds a warning. It is triggered when it feels an intrusion or when a door opens when it should not have. It is how your house tells you, “Hey, someone is at the door!”

How Does a Simple Door Alarm System Work?

At its core, a door alarm sensor functions using a basic principle: the connection and disconnection of a circuit. Here is a basic breakdown:

Magnetic Contacts

A simple door alarm sensor has two magnetic parts: one that goes on the door and one that sits on the door frame. Once the door closes, the circuit is complete.


As long as the door remains closed, the circuit remains unbroken. The alarm system is in a “quiet” state during this time, continuously monitoring the circuit.

Alarm Activation

The two magnetic parts separate once someone opens the door, breaking the circuit. The system detects this disruption.

An image of a door alarm system while sounding off

Sound or Alert

Upon detecting the broken circuit (i.e., open door), the system activates an audible alarm or light indicator to alert the homeowner of a potential intrusion.

To simplify it, think of a line of water that flows between two points: the magnetic connections. When the door opens, it is like putting a block in the way of this water flow, which causes an overflow or a disturbance. This “overflow” is how the alarm system tells you that a door is open.

Remember that door alarms for your home can help you know when someone tries to open your door. Yet, they are only one part of a full home security system. There are also door and window alarms for those looking to expand their security coverage. You may install motion light sensors, cameras, and smart technology in more advanced systems to make your home safer. These devices work on a similar principle—to monitor all potential entry points in your home.

Door Alarm Systems: Why Do You Need to Install Them?

Have you ever wondered why door alarm systems are making waves in home security? Here are the prime reasons why:

  1. Deterrence: Homes with visible door alarm sensors are less attractive to intruders. It is a clear sign you prioritize security.
  2. Instant Alerts: You will know immediately if there is an unauthorized entry. Prompt alerts can be crucial in taking timely action.
  3. Peace of Mind: Whether you are away on vacation or cozying up for the night, knowing your door alarm system is on watch lets you relax.
  4. Increase Property Value: Homes with security systems often have higher resale values. It is a bonus that people looking to buy will like.
  5. Savings: Many insurance companies offer discounts to homes equipped with security measures. It is a win-win!
A locksmith installing door alarm systems

Invest in These First-Line-of-Defense Devices

Door alarm systems are not just good for homes; they are a must. These systems watch over you and give your family great peace of mind. Door alarms are the unsung stars of home security in Pittsburgh. They scare off potential burglars and let you know if there is a security breach in a matter of seconds. In the end, this is not just another cost for your home. It is a small but important investment for your home’s safety and privacy. Make the smart choice: put your homes first, protect them, and keep them safe with door alarm systems.

Locksmith Near Me

Planning to make your home more secure? At Sherlock’s Locksmith, we are more than just your typical locksmith; we are your one-stop shop for top-notch locksmith Pittsburgh services. Whether you want an expert door alarm system installation or want to improve the ones you already have, our team has the skills and knowledge to ensure your home is safe and sound.
Do not leave the security of your home up to chance! Move toward a better, more secure way of life. Turn to the pros at Sherlock’s Locksmith right away to start protecting what is most important. We offer free consultation, so call us to request more information.