Motion Sensors

Motion sensors are a practical solution for improving security, convenience, and energy efficiency. They’re commonly used to automatically switch lights on when someone enters a space, monitor movement for security purposes, and support smart home automation. 

Motion sensors are used across many environments, including homes, offices, retail spaces, warehouses, and outdoor areas.

Motion sensors have a wide range of real-world uses, including: 

• Security systems – detecting movement and triggering alerts or alarms 
• Automatic lighting – turning lights on when motion is detected to improve safety and reduce energy use 
• Retail and commercial spaces – helping monitor foot traffic and improve layouts 
• Home automation – enabling hands-free lighting and smart routines 
• Outdoor areas – improving visibility and deterring intruders at night 

Because motion sensors can reduce unnecessary lighting runtime, they’re often used as a simple way to improve energy efficiency in high-traffic spaces. 

There are three common motion sensor technologies used in residential and commercial settings. 

Passive Infrared (PIR) Motion Sensors 

PIR motion sensors detect movement by measuring changes in infrared heat — usually from people or moving objects. They don’t constantly transmit a signal, which helps reduce power usage. 

PIR sensors are popular because they’re generally: 

• affordable 
• reliable 
• energy efficient 
• suitable for a wide range of indoor and outdoor applications 

Many PIR sensors allow you to adjust sensitivity settings to help reduce false detection. 

Microwave (MW) Motion Sensors 

Microwave motion sensors send out microwave pulses and detect motion by measuring how the reflected signal changes when an object moves. 

Microwave sensors often: 

• cover a larger detection area 
• can detect movement differently to PIR sensors 

They may be more expensive and can sometimes be affected by electrical interference depending on the environment. 

Dual Technology (DT) Motion Sensors 

Dual technology sensors combine both PIR and microwave detection. These sensors are designed to reduce nuisance triggers by requiring both sensing methods to detect movement before activating. 

Dual tech sensors can be useful in certain environments, although correct placement is still important for best performance. 

Correct placement makes a big difference to motion sensor reliability and effectiveness. Some common placement strategies include: 

High traffic areas 

Hallways, corridors, and entry points are ideal locations because they have regular movement and predictable walking paths. This helps improve detection and reduce blind spots. 

Room corners 

Installing a motion sensor in the corner of a room can provide a wider field of view and improve coverage across the space. 

Higher positions (“bird’s-eye view”) 

Mounting motion sensors higher up often improves coverage and reduces obstruction issues. This is one reason why ceiling mount motion sensors are popular in open-plan or commercial environments. 

Above doorways 

Positioning a sensor near a doorway can trigger lights or alerts immediately when someone enters or exits the space. 

Basements and low-traffic areas 

Basements and storage areas can benefit from motion detection because they’re often low visibility areas and may have fewer regular occupants.