What are Motion Sensors And How Do They Work

The first motion sensor was invented in the year 1950 by Samuel Bango named as a burglar alarm. He applied the basics of a radar to ultrasonic waves – a frequency to notice fire or robber and that which human beings cannot listen to. The Samuel motion sensor is based on the principle of “Doppler Effect”. Currently, most of the motion sensors work on the principle of Samuel Bango’s detector. Microwave and infrared sensors used to detect motion by the changes in the frequencies they produce. To understand the working of motion sensor, you first need to know the working of a camera. The camera uses an image sensor and the lens direct light to – when the light strikes the image sensor each pixel records how much light it’s getting. That outline of light and dark areas in the pixels becomes the entire video image.

Motion sensors are applicable for security systems which are used in offices, banks, shopping malls, and also as intruder alarm at home. The existing motion detectors can stop serious accidents by detecting the persons who are closest to the sensor. We can monitor motion detectors in public places. The main part of the motion detector circuit is the dual IR reflective sensor.

What is a Motion Sensor?

A motion sensor is a device that notices moving objects, mainly people. A motion sensor is frequently incorporated as a component of a system that routinely performs a task or else alert a user of motion in a region. These sensors form a very important component of security, home control, energy efficiency, automated lighting control, and other helpful systems. The main principle of motion sensor is to sense a burglar and send an alert to your control panel, which gives an alert to your monitoring center. Motion sensors react to different situations like movement in your living room, doors, windows being unbolt or closed and also these sensors can

• Activate a doorbell when someone comes close to the front door.
• These sensors give you an alert whenever kids enter into some restricted areas in the home such as medicine cabinet, the basement or workout room.
• Conserve energy by using this sensor lighting in empty spaces.

Types of Motion Sensors

There various kinds of motion sensors are available in the market, which has their ups and downs. They are namely PIR, Ultrasonic, Microwave, Tomographic and combined types.

Passive Infrared (PIR) Sensor

All warm blooded animals produce IR radiation. Passive infrared sensors include a thin Pyroelectric film material, that responds to IR radiation by emitting electricity. This sensor will activate burglar alarm whenever this influx of electricity takes place. These sensors are economical, don’t use more energy and last forever. These sensors are commonly used in indoor alarms.

Ultrasonic Sensor

Ultrasonic sensor can be active (or) passive, where passive ones pay attention for particular sounds like metal on metal, glass breaking. These sensors are very sensitive, but they are frequently expensive and prone to fake alarms. Active ones generate ultrasonic wave (sound wave) pulses and then determine the reflection of these waves off a moving object. Animals like cats, dogs, fishes can hear this sound waves, so an active ultrasonic alarm might unsettle them.

Microwave Sensor

These sensors generate microwave pulses and then calculate their reflection off of objects, in order to know whether objects are moving or not. Microwave sensors are very sensitive, but sometimes these can be seen in nonmetallic objects which can be detected moving objects on the outside of the target range. It consumes a lot of power, so these sensors are frequently designed to cycle ON & OFF. This makes it feasible to acquire past them, if you know the cycles. Electronic guard dogs utilize microwave sensors.

Tomographic Sensor

These sensors generate radio waves and detect when those waves are troubled. They can notice through walls and objects, and are frequently placed in a way that makes a radio wave net that cover ups large areas. These sensors are expensive, so they are normally used in warehouses, storage units and also in other situations that need a commercial level of security.

Combined types of Motion Sensors

Some types of motion detectors mix some sensors in order to decrease fake alarms. But, dual sensors are only activated when both kinds sense motion. For instance, a dual microwave or PIR sensor will start out on the passive infrared sensor setting, because that consumes less energy. When the passive infrared sensor is tripped, the microwave division will turn ON; then, if the remaining sensor also tripped, the alarm will generate sound. This combined type is great for neglecting fake alarms, but tuns the possibility of missing real ones.

Thus, this is all about the different types of motion sensors which include Passive Infrared Sensor, Ultrasonic Sensor, Microwave Sensor, Tomographic Sensor and Combined types. We hope that you have got a better understanding of this concept. Furthermore, any queries regarding this concept or to implement sensor based projects, please give your valuable suggestions by commenting in the comment section below. Here is a question for you, What are the applications of motion sensors?

Photo Credits:

• Motion Sensor egbadvancedsecurity
• Ultrasonic Sensor elecfreaks
• Combined types of Motion Sensors ledwatcher