Wired motion sensors for security alarms
Motion sensors or detectors in burglar alarms are designed to detect illegal entry into the premises or territory under protection. Some motion sensors allow their users to implement automation scenarios, such as turning on a light after motion is detected.
How motion sensors work
Motion sensors as part of a security alarm analyze infrared, ultrasonic and other types of radiation from objects in a protected area. If a person’s movement is detected in the detection zone, the sensor fix changes in the parameters of incoming waves and activates a response to the incident.
Once detected, the motion sensor sends a signal to the control panel via radio signal or cable. Some motion detectors send an alarm signal to the central panel of the security company and mobile phones of users of the security system. Motion sensors with a built-in GSM module and a siren can work autonomously.
Types of motion sensors for alarm
Motion sensors for burglar alarms differ in the following parameters:
- According to the principle of operation, motion sensors are ultrasonic, infrared, microwave and combined.
- According to the method of data transmission, wired and wireless detectors are distinguished.
- According to the mechanism of wave processing — passive (work with incoming radiation) and active (create and process waves independently).
- According to the detection zone — volumetric (control the entire area), surface (control the plane) and linear (control of part of the territory with a directional beam).
- At the place of installation, motion sensors are indoor and outdoor.
Classification of motion sensors according to the principle of operation
To protect premises and territory in security systems, infrared, microwave, ultrasonic and combined (devices with different sensitive elements) motion sensors are used.
The most common burglar alarm system is an infrared passive motion detector. Movement is detected by two or four sensitive pyroelectric elements, analyzing the object’s thermal radiation parameters under protection. Infrared sensors are equipped with Frenel lenses that focus and direct infrared rays to the sensors. A reaction occurs when a person appears in the detection zone, and sensor readings begin to differ.
Microwave motion sensors in burglar alarms respond to changes in the parameters of radio waves. A microwave detector can analyze the situation over a large area with various obstacles — radio waves pass through wooden partitions and walls.
The sensor of ultrasonic motion sensor analyzes the sound waves generated by the piezoelectric element and reflected from obstacles. When an object in motion appears in the coverage area, the parameters of the waves change, and the detector is activated.
How to choose a motion sensor for outdoor or indoor installation
Before buying a motion sensor, you should pay attention to the following parameters:
- Ability to configure the sensor; its sensitivity, operating range, etc.
- The presence of “immunity” to animals.
- Angle and radius of motion sensor detection.
- The speed of the sensor’s response to movement.
- Availability of energy-efficient power consumption.
- Protected against splashes, dust, sunlight, etc.
- Protection of the body of the motion sensor from opening.
- The operating temperature of the device.
Installation and configuration of the motion sensor
When connected, a security zone is assigned to the motion sensor. Wired devices are connected to the alarm center using a cable, wireless devices — via a radio signal.
Motion sensors are installed at the height of 2 – 3 meters from the ground in the room’s corners. Do not point it at heating devices and windows to avoid false positives about the device. The motion sensor can be fixed to the wall permanently or by using swivel mounting brackets.
Indoor wired motion sensor MotionProtect Fibra
The MotionProtect Fibra alarm motion sensor works only as part of the Ajax security system. Data exchange with the control panel takes place via the secure Fibra protocol. The wired communication range is up to 2 km when connected via a U/UTP cat — five twisted-pair cables.
MotionProtect Fibra is a motion sensor for the Fibra line of wired devices. This sensor may only be installed by an installer who has been trained and certified for this.
The principle of operation of the MotionProtect Fibra motion sensor from the Ajax security system
The MotionProtect Fibra, a wired motion sensor, detects an intrusion using an infrared sensor. The device detects the movement of a person on the guarded premises, after which it transmits an alarm signal to the alarm control panel. The security system central, in turn, informs users and the security company about the incident or launches automation scripts.
All alarms received from the MotionProtect Fibra motion sensor are recorded in the notification feed of the Ajax application. The owner knows in which room the motion sensor was triggered, thanks to the addressability of the devices.
The response to an alarm is configurable by the alarm user. It is possible to select the function of notification to a mobile phone or the activation of a siren at an armed site.
Fibra data transfer protocol
Indoor wired motion sensor MotionProtect uses Fibra technology to transmit events. The two-way protocol ensures reliable communication between the control panel and security system sensors. Thanks to the bus connection method, Fibra technology instantly delivers alarms, even if 100 sensors are connected to the system.
The Fibra protocol verifies all communication sessions with devices and supports floating key block encryption to prevent device spoofing and sabotage. The Fibra protocol provides regular polling of sensors by the alarm central with a predetermined frequency. Thus, the level of communication with the sensors and their performance are monitored in real-time.
Features of MotionProtect Fibra wired motion detector
The Ajax security system uses several features in the operation of alarm system devices. For the MotionProtect Fibra motion sensor, they are as follows:
- The MotionProtect Fibra, an indoor motion sensor, is equipped with a PIR sensor to detect a person at 12 meters instantly. The sensor uses a software algorithm to analyze the PIR sensor signal to filter out other heat sources. It takes a fraction of a second for the device to determine whether it is a real threat or a false alarm.
- Another default feature is temperature compensation. The motion sensor corrects the sensors’ signal, adjusted for the temperature of the environment. This principle of operation makes the device effective even at air temperatures close to the temperature of the human body.
- The motion detector of the Ajax security system, MotionProtect Fibra has a high detection accuracy with immunity to pets.
- Possibility of transferring the alarm to the monitoring station of the security company. Public and private security agencies accept monitoring only certified security systems that have passed multi-level quality control — Ajax is one of them.