Motion Sensors Guide

Motion sensors are a key component to any home security system. They detect movement, allowing you to know when someone is inside the property, even if a door or window sensor isn’t triggered as they breach the inside. It’s certainly an important security feature to have, but they must be strategically placed in order to get the most benefit from them. This guide will help explain the role of motion sensors in your home security system, how they operate and their many different features.

Think of motion sensors as another line of defense in your home security system. It’s important to know when an intruder has entered your home. While you away from home, motion sensors can pick up on movement; trigger the alarm and alert emergency personnel that someone has entered the home. In addition, they can be installed and set up to sync with security cameras and record any movement in a specific area.

Since motion sensors pick up on movement, they are beneficial to have in more ways than one. They can also do the following:

  • Notify when someone has entered the property, while no one is home.
  • Detect when someone has entered a restricted room inside the house.
  • Detect when a teenager has broken their allotted curfew time.
  • Cut back on energy usage, with occupancy sensor lighting.
  • Notify when someone is at the front door.
  • Be integrated with smart home security systems, some of which provide voice control.

1. Passive Infrared (PIR)

Passive Infrared motion sensors or PIR sensors are one of the most common types found in home security systems today. These detect infrared energy, which is given off from a person’s body heat. So if anyone enters the home, his or her body heat will trigger the sensor with the change of temperature.

2. Active Infrared (AIR)

Active Infrared or AIR sensors send out infrared light beams. If a person or object interrupts the beams, the motion detector is triggered. These are not common in most home motion sensors, rather they are most frequently found in commercial sensors for businesses.

3. Microwave (MW)

Microwave or MW sensors emit microwaves and detect intrusions by measuring the frequency of the reflected waves. If a person is present, the motion sensor will have registered the frequency of those received microwaves. These can cover a larger area than some of the other type of motion sensors, however, they are prone to some electrical interferences, which could result in a false trigger. A false alarm could occur when something so simple as a vibration occurs in an object, such as a curtain moving.

4. Dual Technology

Dual Technology sensors combine the technology of both passive Infrared (PIR) sensors and MicroWave sensors. So this type of motion sensor can detect both infrared energy and measure the frequency of reflected waves. Dual technology sensors are less likely to create a false alarm, since both the PIR and MV sensors have to both be tripped.

5. Ultrasonic

Ultrasonic motion sensors measure the reflection of ultrasonic waves. Ultrasonic waves, or low frequency sounds are emitted throughout a room. If a person is in the room, the frequency changes, activating the sensor.

6. Area Reflective Type

Area reflective type motion sensors use an LED to send out infrared rays. It measures the distance to objects, so if the distance of the ray changes due to an intruder, the sensor will be triggered.

Wireless Motion Sensors

Wireless sensors are easy to install and don’t require any invasive drilling. Many can even be placed without professional assistance. Simply place the wireless motion sensor in the designated area, secure it and it’s ready to be incorporated with the home monitoring system.

Pet Immune Motion Sensors

Pet immune motion sensors don’t pick up animal movements. This is particularly great for dog and cat owners who still want to protect their homes from potential intruders. For this, passive infrared sensors (PIR) are involved. They provide minimal false alarms due to pet interference.

Video Motion Sensors

Today’s motion sensors can be synced with video surveillance. So whenever there is motion, the camera is able to monitor and record footage in that specific area. It’s a great security resource, since it includes a video component for visual home monitoring.

Contact Motion Sensors

Contact motion sensors are for window and doors. So if an intruder enters one of these entryways, the attached motion sensor will pick up the movement. These types of sensors are passive infrared (PIR) sensors, which detects body heat.

If you are installing motion sensors by yourself, without professional installation, you’ll need to know the best locations for your motion sensor placement. It all depends on the layout of your home, the entryways and the amount of traffic that area gets. Most Do it yourself (DIY) alarm systems will include instruction manuals with placement suggestions. Definitely follow these instructions and take the time to actually read it thoroughly. This is one are where you won’t want to wing it! Here are some general placement tips:

  • Place motion sensors in areas that people have to go through. A prime example is hallways or the stairs.
  • Place sensors near front and back doors. These entryways are where most intruders will enter the home.
  • Place motion sensor in areas where an intruder would have to walk parallel, not directly towards the sensor.
  • Don’t place sensors too close to each other.
  • Don’t place sensors close to heat sources, such as heating vents. Keep in mind that some sensors pick up on heat sources.

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