Home Security 101: Alarm Sensor Technologies

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Let’s talk alarm sensors! The word “sensor” tells you what this device is: it’s a methodology for sensing something, and that something is invariably a change in a condition in the protected premises. Think doors opening, temperature changing, glass breaking – you get the picture.

Along with the control panel (the “brain” of the system), every standard alarm systems contains at least one sensor. Today we’re not talking about how these sensors work, but about alarm sensors in general. We’ll cover each alarm sensor in detail in later posts.

Where It All Started

The very first sensors utilized in alarm technology have changed very little over the past century. These are the basic door/window sensors, which make up the core of almost every alarm system – even today. Yes, there are plenty of other types of sensors, but the original magnetic door contact is remarkably close in function and design to what is routinely installed in current systems. And that’s because it works.

Sensor Types

Over time the list of sensors has increased dramatically, and it’s still growing. Here’s a fairly complete list of the standard sensor types installed in homes and business today – and pretty much every one of them can be included in a monitored alarm system.

  • Door/Window Sensor (many configurations, with all performing the same function)
  • Motion Sensor (usually passive infrared, but there are other technologies)
  • Glass Break Sensor
  • Smoke/Heat Sensor (can be one, the other, or both)
  • Carbon Monoxide Sensor
  • Low Temperature Sensor
  • Water/Flood Sensor
  • Garage Door Sensor

As you can see, there are three main sensor categories:

  1. Intrusion sensors
  2. Life safety sensors
  3. Environmental sensors.

Other specific sensors may be available, but generally speaking every sensor fits into one the three groups shown above.

Wireless vs. Hard-Wired

Probably the biggest evolution in sensor technology was the development of reliable wireless sensor technology in the 1980’s. Up until that time, every sensor had to be physically connected to the alarm control panel with low-voltage wiring. That was a lot of work, and mean in many cases that an alarm installer needed to be something of a carpenter as well.

Supervised Wireless

The best wireless sensors are the ones that are supervised, meaning that each sensor needs to “check in” with the control panel on a regular basis. That means if a sensor happens to malfunction – which is rare – or if a sensor were removed from the premises, the alarm system would know, and would report that condition. You definitely want wireless sensors that are supervised.

Long-life Batteries

Wireless sensor technology has also come a very long way in terms of battery life. Today’s wireless sensors can operate literally for years (up to five or six years!) before your system tells you which batteries need to be replaced. And the batteries are common household varieties.

Which is Better: Wireless or Hard-Wired?

Wireless alarm sensors have become the norm in the US home security market, for a variety of reasons:

  1. They are completely reliable, especially when they are the supervised variety.
  2. They are easier and quicker to install, particularly when dealing with existing construction.
  3. They are easier to troubleshoot and to replace, since wiring (the main cause of sensor problems) is non-existent.
  4. They are easier to add and to move. This is especially important if you have a DIY alarm system that you want to move with you to your next home.

One of the few questions raised with wireless sensors is the battery replacement, which is covered above. When all the advantages of wireless are weighed against that one issue, it’s easy to see why wireless sensors have become so popular, and why they are used more often.

Wireless Sensors vs. Wireless Monitoring

And remember, as we discussed last week, the term “wireless” can refer to wireless sensors, or to wireless alarm communication – or both. Some alarm companies sell just the wireless sensors, and may try to pass the system as “100% wireless:” it’s not. When shopping for your home alarm system, make sure you insist on cellular monitoring. And while you are at it, ask the alarm companies you speak with how much extra they are charging for the cellular radio – another important question.

In future posts we’ll cover each of the standard alarm sensors in detail. Remember, we want to provide all the information you need when you are shopping for home security. FrontPoint cares about your peace of mind – and what better place to start than by making sure your home and family are protected by the best technology you can buy? The more you know, the easier it is to make the right decision. See you next Monday!

Comments (8)

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  1. Robert Swanbeck

    I’m a relatively new FrontPoint Security customer, but so far I’ve been very pleased with your service. The only complaint I have with sensors is the garage door sensor. I get A LOT of false alarms, especially in the cold weather, which is annoying. Please let me know when you come up with a new design or replacement because I would be interested in upgrading them.

    • Jamie Botzer

      Hi Robert, I’m glad to hear that you are pleased with our service! And we appreciate your feedback about your garage door sensor. While the cold winter is just about behind us, please let us know if you continue to have sensor issues. We are always more than happy to help get your system working perfectly the way you want it to.

  2. Robert Swanbeck

    I’m a relatively new FrontPoint Security customer, but so far I’ve been very pleased with your service. The only complaint I have with sensors is the garage door sensor. I get A LOT of false alarms, especially in the cold weather, which is annoying. Please let me know when you come up with a new design or replacement because I would be interested in upgrading them.

    • Jamie Botzer

      Hi Robert, I’m glad to hear that you are pleased with our service! And we appreciate your feedback about your garage door sensor. While the cold winter is just about behind us, please let us know if you continue to have sensor issues. We are always more than happy to help get your system working perfectly the way you want it to.

  3. Alan

    Excellent overview, Peter.

    And yeah, I have had my FrontPoint system going on 6 years now, and have not needed to change the batteries in any of my approximately 36 sensors except the image motion sensor you no longer sell anymore anyway (That one is a battery hog, but like I said, you no longer sell it, so it is irrelevant… I love it otherwise though).

    The fact I have never replaced any other batteries in any other sensors is particularly astounding since a couple of the door/window sensors on the highest traffic doors are used all the time, and they only use little cell batteries. In addition, all the sensor types send out three signals every time they are used (for redundancy, to make sure at least one gets through to the control panel). Also, the poor motion sensors are even more busy with traffic, and no replacement in those either, and I have 10 of them! So all the sensors are obviously very very efficient. So I would say in this case, battery replacement barely counts as a drawback vs hard wired.

    When I eventually have to start replacing batteries in the 7-10 year time frame, I will do it with a happy heart. Who could complain about that. And the nice thing is, since 95% of the sensors are supervised like you said, they will report to the control panel when their battery is low, and the control panel will then let me know which batteries need to be replaced.

    Pretty cool tech in every aspect, even when it comes to the normally mundane topic or batteries. And a great company behind it to boot! Thanks!

    • Peter M. Rogers

      Thanks, Alan – Could not ask for a better (or more convincing) testimonial, and from a very long-term customer at that. G;ad you like the new Monday series content – we think folks are really interested in objective information on this technology – and we’re just the folks to provide it. Thanks again!

  4. Alan

    Excellent overview, Peter.

    And yeah, I have had my FrontPoint system going on 6 years now, and have not needed to change the batteries in any of my approximately 36 sensors except the image motion sensor you no longer sell anymore anyway (That one is a battery hog, but like I said, you no longer sell it, so it is irrelevant… I love it otherwise though).

    The fact I have never replaced any other batteries in any other sensors is particularly astounding since a couple of the door/window sensors on the highest traffic doors are used all the time, and they only use little cell batteries. In addition, all the sensor types send out three signals every time they are used (for redundancy, to make sure at least one gets through to the control panel). Also, the poor motion sensors are even more busy with traffic, and no replacement in those either, and I have 10 of them! So all the sensors are obviously very very efficient. So I would say in this case, battery replacement barely counts as a drawback vs hard wired.

    When I eventually have to start replacing batteries in the 7-10 year time frame, I will do it with a happy heart. Who could complain about that. And the nice thing is, since 95% of the sensors are supervised like you said, they will report to the control panel when their battery is low, and the control panel will then let me know which batteries need to be replaced.

    Pretty cool tech in every aspect, even when it comes to the normally mundane topic or batteries. And a great company behind it to boot! Thanks!

    • Peter M. Rogers

      Thanks, Alan – Could not ask for a better (or more convincing) testimonial, and from a very long-term customer at that. G;ad you like the new Monday series content – we think folks are really interested in objective information on this technology – and we’re just the folks to provide it. Thanks again!

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