Motion Detectors

Did you know that a home is burglarized every 14.6 seconds? 73.9% of all burglaries target residential properties. These statistics provided by the FBI reflect how vulnerable residential properties are in the US.

So what do you do to keep burglars at bay? How do you keep your family and property safe? You can obviously use a baseball bat or get a dog, but that won’t really offer you the level of security that comes with technology. To protect your home from intruders, you may want to look into getting a motion detector.

What is a Motion Detector?

Motion sensors and detectors have been around since the seventies and are designed to provide effective security to home owners. Although technological advancements have improved the functioning of motion detectors, the basic purpose and system of this device remains the same. A motion detector is basically designed to detect motion or movement in a designated area and may instantly send a signal to the security alarm system.

Types of Motion Detectors

These detectors come in different shapes and sizes. Here are a couple of examples;

  1. Passive Infrared Detectors - These are one of the most commonly used sensors nowadays and may be found in many home security systems. The device is designed to pick up infrared rays and detect any form of movement.

  2. Active Infrared Sensors - Designed to emit an electrical signal that connects to a light detector. As soon as the beam gets interrupted, it may sound the motion sensor alarm.

  3. Passive Ultrasonic Detector – In theory, an ultrasonic detector sends out high frequency sound waves that are reflected back to the sensor. If any interruption occurs in the sound waves, the active ultrasonic sensor may sound the alarm.

  4. Combined Motion Sensors - You could also choose a combined motion sensor that is designed to detect all kinds of motion, together. These sensors could be useful if you wish to reduce the risk of false alarms.

  5. Wireless Motion Sensor - Wireless motion sensors are mostly used in doors and windows. These could be convenient to place and easy to install. When the device detects movement or motion, it may send signals back to a base device that triggers an alarm.

  6. Motion Sensor Camera - This detector is designed to capture still images when movement is detected. Some motion sensor cameras also generate videos.

How to Select Motion Sensor

These detectors could be placed both indoors and outdoors. When you go out searching for one, you must know why you need it, where you need it, and what your budget is. Apart from this, it is also important that you choose a detector that can be installed easily. There are plenty of DIY models available in the market. If it’s your first time, a sales person should be able to help you in this regard.


Q:What are pet immune motion detectors and how do they work?

A:Pet immune detectors, as the name suggests, are motion detectors, which are not triggered by the movement of animals. They are designed to detect the movement of living beings above a certain weight only and therefore when an animal gets in their range, they do not go off.

Q:Is DIY motion sensor alarm easy to use?

A:Depends on the complexity of the alarm that you have built. Usually constructed with a simple set of items including photocells, 741 Op Amp, a buzzer or alarm, a 9 volt battery breadboard and a 10k potentiometer, you may find it relatively easy to use since you built it. But keep in mind that this will require some basic knowledge of electronics on your part.

Q:What are DIY motion detector alarms and how do they work?

A:These are motion detectors that you can construct yourself with a set of accessories you will find in any major electronics store. Since you are building this yourself, its working will vary according to your design. But as a general principle it will operate just like a typical motion alarm, detecting movements in its predefined area.

Q:How light and sound waves are involved in motion detectors?

A:There are many different detectors that trigger different responses. The most common motion detectors are either passive infrared (PIR), microwave, or ultrasonic. A PIR sensor will detect temperature of a body within its proximity. A microwave sensor when activated omits a continuous wave of radiation which will experience disturbance if an object comes in its path, triggering the alarm. On the other hand, an ultrasonic sensor will omits ultrasonic waves that are reflected back when an object appears in its proximity. Sensors and detectors use different technologies to functions. You can also opt for dual-technology motion sensors depending upon your security needs.

Q:How to keep motion sensor on?

A:In order to keep your motion sensor on, you would need to keep in mind a few important points. You may check if the motion sensor is connected properly to the system, batteries are working fine, and if the system is correctly wired. If you have a wireless system, you must make sure there is no interference in the signals.

Q:Can you tell me about motion detectors how do they use sound and light waves?

A:Motion detectors make use of a beam of light, which crosses the room near the entrance, while the photo sensor is placed on the opposite side of the room. When someone passes through the beam causing it to break, the photo sensor identifies the change in the amount of light, and rings a bell. This way, both sound and light waves are used in motion detectors.

Q:What type of rays do motion sensors detect?

A:There are different types of motion detectors, which use different technologies to detect rays. Passive infrared detectors detect body heat or infrared rays. Microwave detectors make use of microwave pulses and detect motion by reflection of a moving object. Dual technology detectors have combined features of microwave and infrared sensors. Ultrasonic detectors make use of ultrasonic waves to measure the reflection of moving objects.

Q:Do motion detectors work in complete darkness?

A:Typically, motion detectors use infra-red rays to detect motion and they work just fine in complete darkness. Motion detectors do not need to emit any light or infra-red of their own, as they rely on picking up infra red radiation given off by people. So, you would not need to light up your area for the motion detector to work properly.

Q:Will electrical tape stop a motion detector from working?

A:If you are using an electrical tape to stop your motion detector from working, it may not be very effective. Although, electrical tape may look black, but it is not completely opaque, so infra red rays can pass through the tape and are likely to be detected by the motion detector.

Q:How to disable a motion detector?

A:It is easy to disable those motion detectors which are battery operated or wireless. For these motion detectors, you will only need to remove the battery. If your motion detector has an alarm system, you will only need to switch the alarm off. However, if you want to completely stop your detector, you would need to deconstruct it by removing battery and cables. If you have a wired detection system, you may need professional help to disable the motion detector.

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