Wireless motion sensor alarms are commonly used in homes or office premises as a security protection device. As the name suggests, an alarm is set to turn on, when the device detects the presence of someone (human or animal) in the range of the device, when they shouldn’t be. The movement or motion of the intruder is detected by the sensor and the signal is transferred to the alarm section for warning the concerned person about the threat.
Why should you use motion sensors?
Motion sensors are solely used for the purpose of sensing an intruder and alerting the monitoring person about the uncalled visitor. The alarm system can be used to work when you are away from your house or only at night. A motion sensor can also be programmed to work along with a video recorder, so that all the events can be captured live with a security camera.
Wireless motion sensors are mostly installed at front doors, garages, alleyways, warehouses, and at any place where no other security measures are taken to guard the premises.
Thus motion sensors can be used to signal the doorbell when someone reaches the front door. Alarms can also be triggered when people or kids or even pets approach restricted rooms, basements, warehouse offices and so on.
Motion Sensors – Basic Types
Basically motion sensors can be divided into two types. They are active and passive sensors. An active motion sensor uses any one of the three kinds of sources to identify motion. They are infrared light, microwave radiation and sound waves. An active motion sensor will have a transmitter and receiver. The transmitter sends out the energy signal and this is received by the receiver. When a person or animal moves in between the area of the transmitter and receiver, the intermediate beam is cut and the warning alarm is turned on. One major problem in using active motion sensors is that the distance between the transmitter and receiver will be very small. The line of sight will also be poor.
Passive sensors uses infrared energy to detect the objects in its field of view. Passive devices does not have a transmitter nor a receiver. Thus, the device does not emit radiations, but only absorbs the ones emitted from the object. More of this type will be explained in one of its applications – the PIR sensor.
Wireless Motion Sensor Types
All the motion sensors available in the market are wireless. This makes the device easy to setup, and is also easy to communicate with the other wireless security devices.
Passive Infrared Radial (PIR) Sensor
In PIR sensors, the sensor part is basically a pyro-electric device. An electric charge is generated when the device is exposed to infrared radiation. In PIR sensors the infrared energy mainly refers to the body heat. As this body heat is above absolute zero temperature, the sensor accepts the energy in the form of radiations. This temperature level will be different for humans that move and for fixed trees or walls. Thus the change in heat is detected “passively” in the form of infrared radiations and an electric charge is thus generated. This charge varies according to the amount of infrared striking the sensor, and a voltage is generated, which is passed on to trigger the alarm. More about the PIR based security system is provided in this article with circuit diagram, working and applications.
Know more at PIR Sensor Based Security System.
- Dual Technology Motion Sensors
A combination of both sensor technologies (active and passive) are commonly used to make motion sensors, in order to minimize false alarms. The companies providing dual technology motion sensors boast that the mixing up of PIR sensors and microwave sensor will reduce false alarms drastically as both the sensors have to be tripped before triggering the alarm. False alarms are not only caused by animals, but also by electrical failures, high and low power spikes, faulty manufacturing, user errors and so on.
- Area Reflective Type
Here, distance is one main parameter that is used to observe object movement. An LED is used as a transmitter which sends out the infrared rays. When an object moves, the rays reflects back to the receiver which calculates the distance to see whether the reflection came from its assigned line of sight. If it is, an alarm is triggered.
Sensors made out of microwave motion pulses transmits the wave to its maximum range and measures the reflection off moving objects. Though the range of transmission is more than infrared they are costly to buy and are susceptible to electronic damage.
Ultrasonic motion sensors are also the same as microwave. The transmitter sends the ultrasonic wave and waits for the object to hit a moving object. This response is sent to be amplified and thus triggered as a warning signal.
In this method, the motion of the person is detected through vibration. This method is usually used for small home security purposes. The sensor uses a small mass on a lever. This is connected to an alarm which turns on as soon as the lever vibrates due to object movement. Only small applications succeeds with this sensor, and may turn out unreliable for higher security systems.
Motion sensors can be used in contact applications where passive infrared sensors are used on doors or windows. When the door is opened, the alarm is turned on.
Most false alarms are caused by animals who walk past the line of sight and trigger the alarm falsely. The dual motion sensor can be designed to ignore a large animal or small animal group by adjusting the sensitivity levels of the sensors.
The combination of video cameras with the help of advanced signal processing is one main advantage of wireless motion sensors. They can be programmed to start recording as soon as the motion sensor senses motion. Thus the video is only recorded when needed, and not much memory is wasted for storage. Nowadays, with the help of smartphones and internet connectivity, it is possible to get alerts in the form of texts and emails as soon as motion is detected, remotely. You can even design the sensor to alarm the intruder by introducing fake dog barks or emergency sounds, as soon as motion is sensed.
Like cameras, motion sensor lights can also be introduced to turn on only when a motion is sensed. This will help in cases when the security guard or the resident is nearby. This may even startle the intruder. Another advantage is that no electricity is wasted by turning on the light the whole time.
Wireless Sensor Mounting Guide
If you have some expert to install the motion sensor, you do not need to worry about anything. But, if you are planning on installing the system on your own you have to be sure about the installation process, place of installation and trap points.
Make sure to install the sensor in a place where no sudden heat changes occurs. For example, a heating vent, stoves, and even places where direct sunlight shines in your room.
Specific trap points must be chosen to mount the sensors. These must be places where where an intruder cannot avoid walking through, like the stairs, hall/garage/back doorways, place where valuables are kept. Put yourself in the intruder’s shoes and assess the points yourself.
Given below are the reviews of some of the most used wireless motion sensor alarms.
Wireless Motion Sensor Alarm Product Reviews
Wireless Home Security Alert Alarm System Kit Type QH-0514 by 1Byone
The Qh-0514 model by 1byone has a wireless receiver and 2 wireless transmitters inside the box, along with the instruction manual and a warranty card. The receiver has a pretty basic design with 3 LED bulbs and a speaker below for the alert sound. On the right hand side, a 6 volt DC input port is placed above the mode switch. The left hand side has a power switch just above the sound and flash switch band. The back of the receiver has 2 holes for mounting the device on walls. Beneath is the battery slot which hold 3 C-size batteries. The transmitter has a large PIR sensor on the front just above a small blue LED light which illuminates when movement is detected. On the back, there are holes to attach the transmitter to the wall. Below it is the battery slot which holds 3 AAA size batteries. According to the manual, you can also use a 4.5 Volt dc power supply to power these transmitters.
When the receiver is switched on, the 3 LED’s at the top will illuminate in bright blue for 15 seconds. In this time, you must trip the sensor by walking past one of the transmitters. The receiver will beep twice to confirm that the link has been made. You can then do the same to the other transmitter by pressing the auto learning code button first to initiate another link setup. The receiver has 3 selectable operation modes – sound only mode, flash only, all sound and flash. Also, you can set the transmitter to chime, low or alarm. Chime is a loud beeping sound which repeats itself four times. Low is the same sound, but with low beeping sound. The alarm is the loudest of all, with a 100dB sound. This safety driveway alarm has a range of up to 100 meters and a maximum detection range of 8 meters.
The transmitters have a curved shape, therefore they also have a wide sensing angle of about 45 degrees. The receiver is capable of picking up transmitted signals up to around 50 meters and the system allows you to easily add more receivers or sensors by simple matching process. A great feature is that when you switch off the receiver or change the batteries in the receiver or transmitter you need not have to relink all the devices.
Driveway Alarm – Wireless Motion Sensor Alert System with Long Range Receiver & Transmitter by Bubba’s Home
Increase protection for your homes and office by installing the wireless motion sensor alarm system with long range receiver and transmitter by Bubba’s Home. This model is redesigned to offer easier programming and have also introduced more alarm options. The loudest alarm sound has a frequency of 90 dB. The warning sounds can be set in 3 modes – chime, low and alarm. The package consists of a single receiver and transmitter. For one receiver, almost 50 transmitters or sensors can be paired. The transmitter uses AAA batteries and the receiver uses C-sized batteries. This motion sensor can be used on driveways, garages, alleyways, loading docks, waiting rooms, front offices, porches, entryways and so on. Both the transmitter and receiver are made of highly durable materials and are weather resistant. The device is easy to setup and can be mounted easily on flat surfaces as well as on walls. You do not need any technical knowledge to install it and is highly affordable.
CWA2000 Wireless Motion Alert System by Chamberlain
The CWA2000 series Wireless motion sensor by Chamberlain has one base receiver and one sensor. Additional sensors can be added on to increase the security. The sensor used is absolutely weather resistant and hence can be used in the open. The device can detect motion almost 30 feet away. The receiver and transmitter can be kept to a maximum distance o almost half a mile. Convenience in installation and affordability are additional features of this product. The sensing expansion is maximum up to 4 sensors. The sensor can be powered using a dc adaptor. During power failure, the sensor will need 4 AA alkaline batteries for it to work. If this device is installed for vehicle alert, the best mounting position is about 4 feet high and between 10 to 20 feet back, and angled to see the back of the car after passing the sensor.
HA-434RTL Wireless Home Garage Driveway Business Office Motion Alert and Alarm Security by Skylink
The motion sensor model HA-434RTL by Skylink is known for its indoor and outdoor use, and it’s incredible operating range of 800 feet. The device can be set to detect movements up to a range of 40 feet. The product includes a transmitter and a receiver. The single receiver can sense up to a maximum of 16 sensors in 4 zones. The device includes 3 operating modes to alert motion. One of the modes includes the audio indicator with many sounds. Another mode is the alarm mode, where a sound with a maximum frequency of 95 dB is used to scare away the intruder and also warn the owner. Another mode is the alert mode which omits beeps when the sensor detects motion. A Supervised Sensor is also included to monitor the sensor batteries to let you know when the battery life is getting low.
Choice Alert Wireless Alarm System Motion Sensor by GE
The choice alert wireless motion system by GE is ideal for large living rooms where conventional alarm systems may not be useful. This device is useful to monitor and sense movement in every corners of a large area. This motion sensor detects movement up to 40 feet away and easily mounts in discreet, out of the way areas. A 110 degree detection area ensures you more coverage and is perfect for monitoring large living room, playrooms or hallways. The device is also weather resistant which makes it ideal for outdoor areas like backyards and entryways. To install and link to your choice of control centre, you need to install a 9 volt battery. To connect to your control centre, press and hold the LEARN button on the control centre until you hear a short beep followed by a long beep. Then release the button. Then, press the zone button that you would like to assign the sensor to and that particular zone LED will flash. To activate your sensor, press the LEARN button on the inside of the battery compartment. The LED indicator on the control centre will stop flashing after the beep. This confirms that the sensor is linked. To mount, use the provided ball head mount and screws. Best way is to mount the sensor 5 or 6 feet from the floor in a corner for best coverage. Once the device is mount, adjust the angle to get maximum coverage. The sleek, compact design fits easily on a table or shelf and will go unnoticed. This device has a whole new level of functionality and provides security and convenience.