As burglar alarms design and installation specialists in the UK, we spend considerable time discussing and recommending an ideal type of burglar alarm sensor for each area we wish to protect in a property. So here goes our most comprehensive list of burglar alarm sensors, how they work, when and where to fit them, and when not to use them.

Burglar Alarm Sensors can be broadly classified into standard or regular-use sensors, specialist sensors, and external sensors.

Here’s a detailed list of the most commonly used types of burglar alarm sensors.

Standard Sensors

1.     Motion Sensors

The most popular solution for intruder detection is a motion sensor, also known as PIR (Passive InfraRed) detector.

A standard motion detector is the cheapest way to protect a typical room with multiple entry points like doors and windows compared to individual protection for each entry point.

How does a motion sensor work?

PIR-based Motion Detection detects infrared energy emitted by objects (humans and animals) in the form of heat. PIR motion sensors are small, inexpensive, low-power, easy to use, and don’t wear out. Most PIR detectors cover a 90-degrees to 150-degree range, so they are recommended to be mounted on the corner of a wall where possible. They also work well day and night as infrared energy is detected irrespective of light. Once a motion sensor detects movement, the control panel will be notified of the movement.

Recommendations for motion sensors

1. PIR detectors are to be mounted, facing key entry points like windows and doors, at 1.8m to 2.5m height depending on the make and manufacturer’s specifications.
2. It is recommended to have motion sensors in every room on the property with direct access from outside. So have motion sensors fitted on all ground floor rooms, including hallways and lobbies.
3. You would only require one motion sensor per room unless the rooms are substantially bigger or you have parallel doors or windows which cannot be covered by a single sensor, like a through lounge.

Maintaining Motion Sensors

Your motion sensors are relatively easy to maintain. They have batteries in them that are changed on service visits. Most professional grade alarms will notify the control panel if they have any faults. Common motion sensor faults include low battery warnings, tamper warnings, supervision loss, and damages caused by cleaning around them and knocking them.

2.     Magnetic Door Contact

Magnetic contact, also known as door contact or window contact, is the second most popular alarm detection device. As its alternative name suggests, it is commonly used to protect the most commonly used entry points – doors and windows.  It consists of 2 parts. A smaller magnetic piece and a typically slightly larger unit with the other magnetic piece and electronic components allow it to communicate with the control panel.

How does a magnetic door contact work?

The two separate units of magnetic door contacts are fitted on the door/ windows and its frame, so when the door/ window is closed, the two pieces sit next to each other, engaging its magnetic field. If the door is forced open, the magnetic field is disturbed, and the contact will notify the contract panel.

Recommendations for door contacts

1. Every alarm must have a magnetic contact for the main entrance – front door. When the system is ‘armed away’ or ‘fully armed,’ it is usually programmed to give a timer delay (usually 30 to 45 seconds) to enter the property and disarm the system. When the system is in an ‘armed home’ ‘part arm’ state at night, the same door contact will be programmed to set the alarm off instantly if someone tries to open the door and break in.
2. It is also recommended to have door contacts fitted for every external door of the property for the following reasons.
   • Most break-ins happen through the front or back doors, and a door contact offers effective perimeter protection before someone enters the building.
   • You cannot turn on a burglar alarm with any of the external doors left open.  Door contacts on every door are the easiest way to ensure all doors are closed before you leave the property.

Recommendations for door contacts

Your burglar alarm door contacts are relatively easy to maintain. They have batteries in them that are changed on service visits. Most professional grade alarms will notify the control panel if they have any faults. Common door contact faults include low battery warnings, tamper warnings, supervision loss, and the more embarrassing door contact falling off the door – often caused by humidity or slamming the door.

3.     Pet-friendly Motion Sensors

Pet-friendly motion sensors are motion sensors that are designed to ignore the movements of pets when the burglar alarm is armed so false alarms can be avoided.

How does a pet-friendly motion sensor work?

Most professional alarm manufacturers create pet immune filters to cover the PIR sensors, so they can ignore heat detected by smaller animals. Most burglar alarm sensors work well with pets up to 38 kilos.

There are also pet-friendly PIRs that simply mask the lower part of the detector to ignore the movements on the floor completely. These tend to work only with smaller pets (typically up to 20 kilograms), the pets that stay in-ground and do not climb on furniture and windows.

Obviously, the first category of sensors is better, and the second category does not work well if you have active or large dogs and most definitely not with cats, as they love to climb on furniture.  

Other factors affecting the performance of pet sensors are the size of the room it has to cover, the type and size of the furniture, and your pets (numbers, size, and how active they are, etc.) And please be warned, as many secret recordings have proved, your pets can behave very differently when you are away.

It is best to seek advice from professional engineers to decide if a pet-friendly sensor is suitable for the room, as sometimes it is better to go for perimeter protection to make sure you do not get false alarms.

Recommendations for pet-friendly motion sensors

1. Location and angle or sensors must depend on the size of the room, entry points they are designed to protect, furniture, and windows your pets could climb on.
2. Pets have secret lives! So, do not assume your pets only go to certain rooms or only climb on certain chairs, etc. Pets tend to behave very differently when you are not home.
3. If in doubt, and if your security installer advises you, opt for perimeter protection using magnetic contacts, curtain detectors, and shock detectors. Pet-friendly motion sensors in large rooms and rooms where large furniture is in place are a hotbed for false alarms.
4. Consider how large and how active your cat or dog will be in a few years (a month’s time in some cases) when you plan for your home security with the alarm engineer.
5. Are you planning to build extensions or make internal layout changes? Discuss the plans for designing the system so costly replacements and amendments can be avoided.

Maintaining Pet-Friendly Motion Sensors

Your pet-friendly motion sensors are just like standard motion sensors and are maintained just the same. They may require more frequent battery changes, as with pets roaming around, the sensors are more active than a standard sensor.

4.     Shock Sensors

Shock sensors, also known as vibration detectors, as the name suggests, are designed to trigger alarms when they detect shockwaves when windows or doors are broken into. This allows the shock detector to send an alert to the control panel to trigger the alarm.

Shock detectors are ideal for use in windows and sliding doors that are at higher risk of a break-in. So, locations include back or side patio doors, sliding doors, and all windows with direct access from outside.

Recommendations for shock sensors

1. If the make and model of the shock sensor allow it, adjust shock sensitivity based on the make, location, type, and size of the window/ door it is fitted to.
2. Shock sensors are ideal for perimeter protection, so use them if you have large or active pets and wish to arm the system while inside the house.

Maintaining Shock Sensors

Your burglar alarm shock sensors contain batteries that need changing during service visits. Most professional grade alarms will notify the control panel if they have any faults. Common shock sensor faults include low battery warnings, tamper warnings, supervision loss, and false alarms caused by external parameters.

5. Curtain Sensors

A curtain sensor is a type of motion detector that is specifically designed to be installed near a window and uses infrared or other technology to detect changes in the movement of the curtains or when an intruder enters through an open window.

How does a Curtain Sensor work?

The curtain sensor creates an imaginary wall and when it is disturbed, the sensor will trigger an alarm, alerting the homeowner or security system of potential intruder activity. This type of sensor is particularly useful for preventing burglaries through windows, as it can detect even subtle movements of the curtains.

Recommendations for Curtain Sensor

1. Ideal for use in the bedroom and other first-floor windows which can be accessed easily from flat-roof areas, balconies, or single-story extensions.
2. Any bedroom window that you wish to protect when your alarm is armed in part-set (homestay) mode/ partition.

Maintaining Curtain Sensors

Curtain sensors require regular check-ups, testing sensors, periodic battery replacement, and sensitivity adjustment where possible.

Specialist Sensors

When it comes to specialist sensors to serve specific purposes and protection on your property, here are the types of sensors you might be looking for.

1.     Camera Motion Sensors

The camera motion sensor is also a PIR sensor used along with CCTV cameras to detect motion. These sensors work like the PIR motion sensors alarms and detect any motion by measuring the heat emitted from different objects around them.

However, there are other types of motion alarm sensors for cameras as well. It includes the dual technology sensor and microwave occupy sensor that works on more complicated algorithms and technology.

How Does a Camera Motion Sensor Work?

A camera motion sensor will record only when there is motion around. It will save energy and bandwidth. Some camera sensors take multiple pictures and send them to the alarm’s smartphone which can play into an app.

Recommendation For Camera Motion Sensors

1. In some camera motion detectors, you can adjust the sensitivity level at the time of installation. Doing so will minimize the chances of false alarms and triggers.
2. If you have a large area of land, installing motion sensor cameras around the property perimeter gives you comprehensive protection and safer premises.
3. When choosing the camera motion sensors and detectors, make sure to choose depending on the range, mounts, sensor technology, and ease of installation.

Maintaining Camera Motion Sensors

You will need to maintain the motion sensors camera to protect it from dust and debris. It can not only affect performance by interfering with infrared signals. Therefore, use a microfiber cloth to clean the detector screen once in three months or six months. As these are completely wireless sensors, they also need their batteries regularly changed.

2.     Quad/ Dual Tech Detector

Quad sensors are dual functionality sensors and are one of the most beneficial burglar alarm sensor types. The quad intruder sensors have a combination of passive infrared technology and microwave sensor technology.

The dual-element PIR sensors with digital processing channels in these sensors increase efficiency and accuracy. The mechanism of these detectors is similar to motion sensors but best to be installed in heat rooms, garages, conservatories, or areas of extreme temperature(too hot or too cold).

If we talk about one of the best quad sensors, Visonic’s quad sensor has cutting-edge technology, a fully digital PIR motion detector, and pet immunity. It is compatible with the alarm system wired type.

3.     Glass Breaker Detectors

Glass-break detector sensors are specialized home alarm sensors you can integrate with your security alarm system. When a glass-break detector is installed, the alarm will go off whenever an intruder tries to break a glass window or door. Unlike the traditional security system that is only efficient in detecting an intruder entering the premises, the glass-break detector adds more to the security of your property.

How Does a Glass Breaker Sensor Work?

The acoustic glass-break detectors have in-built microphones that will efficiently detect the sound of glass breaking in your property. Most of the detectors have dual-sound detection that will decrease the chances of false alarms.

The dual-sound detection will detect a low-pitched sound when someone hits the wall and a high-pitched sound of shattering glass. However, these are more complicated sensors that follow a two-step process. The sensor will wake up when the sound amplitude reaches or exceeds a particular level. Then, the sound is analyzed before the alarm goes off to send an alert.

Recommendation For Glass Breaker Sensor

1. Depending on the make and model, you don’t need to install separate sensors for multiple windows, but one sensor has a decent range to cover the most area. However, you will need to consult with your security installer to ensure the product meets the specification.
2. It is recommended to install the sensor in the area of your home with large windows or sliding glass doors with the highest vulnerability to break-ins from wild animals and thieves.
3. Although the specialized service providers will know the optimal place for sensor installation, you should ensure that they install it near the windows and glass doors to increase efficiency.

Maintaining Glass Breaker Sensor

The batteries installed in the glass-break detector will need replacement often as recommended by the manufacturer. In most systems, the device is smart enough to tell you when the battery is low, and you won’t have to keep the check if the battery needs replacement. In case of other errors or problems, you will need to get specialized security providers to service the sensors for you.

4.     Ceiling Sensors

Ceiling motion sensors are a type of occupancy sensor placed in different places on the ceiling. These sensors are capable of detecting occupancy patterns across different sections of the ceiling. The sensors are designed to fit well with the ceiling décor and provide protection unnoticeably.

Ceiling Sensors provide 360-degree coverage of space and can detect the movement of objects even if they are not visible to the naked eye. They are typically installed in areas with high ceilings, such as warehouses, warehouses, and other large buildings, where traditional motion sensors may not be effective.

How Does a Ceiling Sensor Work?

The mechanism of occupancy sensors uses the PIR motion-detecting sensors and will get triggered on any motion within the given range of the detector. If no movement is detected, the space will be determined as unoccupied, and switch off the lights. The wired detector by Visonic is one example of a very accurate, reliable, and false-alarm immune detector.

Recommendation For Ceiling Sensor

1. The ceiling sensors are very accurate with the low-noise dual-element detector and 360 degrees detection. Therefore, ceiling sensors are a great choice for rooms with multiple entry points and windows in parallel walls, saving the need for multiple wall-mounted sensors.
2. When choosing the placement for ceiling sensors, choose the spaces with ceiling heights of 8 to 12 feet. Also, sensors should be mounted at least 6 feet away from HVAC vents.
3. Ensure that the bookshelves, bookcases, and other tall furniture are not preventing the sensor from working efficiently.

Maintaining Ceiling Sensor

Although you will need the services of specialized security system companies to install the house alarm sensors on the property, maintenance of your security system is also necessary. The batteries are pre-installed, but you will need to replace them after a few years.

5. Shock Door Contact

Shock door contacts are magnetic door contacts with built-in shock detectors. Shock door contact sensors are directly installed on the doors and windows.

How Does a Shock Door Contact Sensor Work?

The shock door contact sensors provide dual functionality as magnetic contact and shock detector. Whenever a door is opened, the magnetic reed detects the movement and sends the alert to the system. And if the door is slammed open or broken into, the shock detector will pick up the vibration.

Recommendation For Shock Door Contact Sensors

1. The shock door contact sensors can be installed on windows and doors alike. These sensors are usually installed in the frames of doors and windows, just like a door contact is.
2. You should prefer to choose a dual detector with contact and shock sensors in case of glass doors and windows.
3. They are recommended for the back and side doors, but not the front doors of the property.

Maintaining Shock Door Contact Sensor

The shock door contacts are usually easy to install, but you should choose a vetted security services provider to install the system for the best range and coverage. However, when it comes to maintenance, make sure that the detectors are installed at enough distance to protect from rain, moisture, heat, etc.

6.     Smoke Detectors

Smoke detector sensors are alarm sensors installed on commercial or residential property to detect any fire. The smoke alarms will detect the particles in the air with the smoke detection technologies.

How Do Smoke Detectors Work?

Ionization smoke detection and photoelectric smoke detection are two technologies used in smoke detectors. If we talk about the first one, it is more efficient and responsive than photoelectric detection.

Ionization sensors have safely shielded radioactive material installed that is electrically charged or ionized the air molecules between the metal plates. As a result, the electric current flow between the plates. The particles entering the chamber attract the ions to carry them away, resulting in reduced current. When the particles enter the chamber at a higher rate and block the current flowing, the particles are detected, and the alarm will go off.

When it comes to choosing the right smoke detector, we recommend ionization sensors for your residential properties. These detectors are more responsive and can quickly detect small black soot particles in a smoldering fire. However, the photoelectric ones are more sensitive to large size particles of white or light color.

7.     Heat And Smoke Detectors

The heat and smoke detectors are designed to detect smoke particles, temperature changes (heat detection), and even carbon monoxide levels in your property’s air. The detectors usually have triple smoke, heat, and carbon monoxide sensors.

Heat and Smoke Detector

You can also use stand-alone heat detectors to replace the all-in-one detectors. The stand-alone heat alarms are ideal for installation in the kitchen, where smoke detectors might not be the right fit. The heat detectors react to the temperature change caused by the fire. Please note, some manufacturers only offer smoke and heat sensors, while others only offer heat only detectors

There are rate-of-rise detectors as well as fixed temperature detectors. For instance, if the baseline temperature is reached and the heat rises rapidly, the alarm will go off. If the rise in temperature is more than 15 degrees per minute, the alarm is activated.

8.     Carbon Monoxide Detectors

Carbon monoxide detectors get triggered on the emission of odourless and colourless carbon monoxide, which can be a serious hazard to the lives of occupants. The home’s indoor quality decreases with the release of CO, and it can be a common instance resulting from a stove leak, furnace leak, etc.

The real hazard is the contact of CO with open flame leading to a fire outbreak. Therefore, a carbon monoxide monitoring sensor can help you ensure that your home’s air is safe to breathe and that there are no chances of fire. There are three types of CO sensors: biometric sensors, metal oxide semiconductors, and electrochemical sensors.

The biometric sensors have a gel whose color will change by CO absorption, and the alarm goes off. The second type has a silica chip that detects the CO when electrical resistance is lowered, and the alarm goes off. Finally, electrochemical detectors have electrodes with a chemical solution that detects the electrical current changes due to contact with CO, resulting in an activated alarm.

9.     Flood Detector

Flood detectors are also one type of house alarm sensor to detect any water overflow, leakages, etc., whether at home or away from your property. Having a flood detector on your property is beneficial as water damage is the second highest reason why you might need a home insurance claim.

The best place to install the flood detectors is a basement or specific areas of your home with a probability of water damage. The sensor has two metal prongs at the bottom, which detect water. If there is a water leakage, the prongs get wet, and the alarm activates.  

You will need specialized technicians to assess and install the detectors and connect them to your home alarm system. However, the areas you should consider for flood detectors can be near your laundry area, water heater, crawl spaces, and plumbing fixtures.

External Sensors

Finally, the third category of burglar alarm sensor types is external sensors. External sensors, aka outdoor sensors, are installed, as the name suggests, external to the property to stop intruders in their tracks even before they reach or break into the property. These sensors work on different or similar technologies capable of avoiding external elements that can cause false alarms and are placed in IP-rated weatherproof casings.

1.     External PIR detectors

External PIR detectors are similar to standard PIR detectors and use passive infrared to detect any movement outside your property and activate the alarms in case of unusual movement.

External motion detectors can only be fitted in back gardens and side alleyways and not to front of the property, so to avoid false alarms caused by owners or visitors triggering the alarm by mistake.

2.     External Camera PIR detectors

We already talked about camera motion detectors with PIR technology that activates the camera and starts recording when a movement is observed.

External camera PIR detectors not only allow for the installation of the fully wireless external sensor to pick up movements and trigger the alarm but by having cameras in the sensor when it picks up a burglar’s presence in the perimeter of the property, it will also take pictures. This, in turn, will be sent to your smartphone app to notify the alarm panel, allowing additional options for reaction.

Here, you can check out Visonic’s wireless tower cam PG2, an outdoor PIR motion detector.

3.     External Door Contacts

Similar to internal door contacts, the magnetic technology in external door contacts detects when the door is closed or opened, therefore, alarming you about an intrusion from outside. External weatherproof door contacts are fitted externally on doors, windows, shutter doors, and gates, of residential and commercial properties.

Visonic’s outdoor magnetic contact detector is good with PowerG wireless magnetic contact. Due to its weatherproofing, it provides efficient protection even in severe weather conditions. Besides, it is fully wireless, working on batteries.

External door contacts are excellent for front and side gates, and when alarm is armed, it can trigger the alarm and/or send notifications as soon as the gate is opened.

4.     External Curtain Detectors

Curtain detectors provide a shield against the doors, windows, and entranceways from the intrusion of alien people before they enter your property. Visonic’s outdoor curtain detector is an advanced PowerG wireless detector that is weatherproof, pet-immune, and very accurate & efficient.

You can check the outdoor curtain PIR detector from Visonic here.

5.     External Flood Light Motion Detectors

The main concern outdoors of your residential or commercial property is to prevent external intrusions by activating an alarm in case of unusual movements. You can choose flood light motion detectors that serve the dual purpose of lighting up your outdoors and protecting your property without getting noticed.

You may or may not need to purchase flood lights with motion detectors. All you need is a specialized technician or service provider to integrate the motion sensors with your flood lights.

Key Takeaways

As you can see there is 20 types of sensors in this listing. Rest assured not all burglar alarm manufacturers make all of these sensors. Typical DIY manufacturers like Yale and Ring usually only make the motion sensors, door contacts and possibly some range of smoke sensors. Depending on the property layout and your typical usage, it is important to consider what kind of sensors suit your requirements best and hence the most suitable alarm product that integrates all these products the most.

Talk to us to for a free consultation on protecting your home or business. We work with the largest choice of installed security products in UK and offers the widest choice of self-monitored, monitored, guard or police response and a wide options of smart alarms and home automation options.