Home Security: The Motion Detector

motion-detectorIn an age where crimes and burglary attacks are rampant, securing one’s home is a top priority of home owners. Home security has advanced beyond mere locks and bolts. This is the era of home automation. An automated house is one in which every device or system can be accessed, operated and controlled from a mobile device via Ethernet or Wi-Fi. The motion detector or sensor is a noteworthy example of an automated home security system.

The motion detector is a device capable of ‘detecting’ motion and alerting the necessary personnel. The user of a motion detector sets it to detect moving objects, especially people, and signal the user.

How Does It Work?
Motion detectors are usually placed around doors and windows and are activated or ‘armed’ most times at night. It makes use of either one or a combination of multiple technologies to detect movement around such areas. Once movement is detected, the sensor is tripped and a signal is sent to the security system’s control panel and then to the monitoring centre which could be the user’s mobile device, if the user is not home. Thus, the user is alerted to a potential threat or burglary attack in his home. This is the beauty of home automation.

Technologies Employed
The technologies used in motion detectors include:

Passive Infrared (PIR) technology
This is the most widely used technology in motion detectors. Humans emit black body radiation at mid-infrared lengths. Passive infrared sensors are sensitive to and can detect this radiation within a specified distance. PIR sensors do not emit any energy or radiation, hence the name ‘passive’.

Microwave (MW) technology
Motion detectors using this technology can cover a larger area than the PIR sensors. However, they are susceptible to electrical interference and are generally more expensive. The working principle involves sending out continuous microwave pulses and measuring the phase shifts reflection of such pulses off a moving object.

Ultrasonic Technology
This technology is similar to the MW technology, but instead of emitting microwave pulses, the detector emits ultrasonic waves and measures the reflections off nearby moving objects. A major drawback of ultrasonic sensors is their sensitivity to motion even in areas not required. This is often due to reflections of the ultrasonic (sound) waves around corners.

Dual Technology
Most modern motion sensors combine features of two separate technologies in an effort to reduce false triggering and alarms. Usually, the PIR technology is combined with the MW technology. In this case, for an alarm to be triggered, the two separate sensors must trip together. This lowers the possibility of false alarms.

Some detectors combine the motion detection with video camera features. Once motion is sensed or detected, the camera is immediately triggered and starts recording.

Motion detectors should be mounted or installed in areas where there are no heating vents, around the stairs and hallways to increase their effectiveness. The motion detectors are clever ways of stalling, disrupting and preventing intruders and burglary attacks on homes. Thus, they are essential features of a home security system.

Fire Alarm and Detection: Smoke and Heat Detectors

Home security is not only concerned with preventing burglary and other criminal attacks on the home, it also involves the safeguarding of lives and properties in the home against fatal accidents such as fire outbreaks. A fire alarm and detection system is designed to detect fire outbreaks in buildings and send out an identifiable alarm to the concerned parties. The system consists of smoke detectors, heat detectors, control and repeater panels, alarm bells and break glasses.

What Are Smoke Detectors?

Smoke detectors are devices capable of detecting or sensing smoke and signalling a warning to either the homeowner or the fire authorities, depending on the manner in which it was programmed. There are basically two types of smoke detectors: ionization and photoelectric smoke detectors.

ionization-detectorThe ionization detector uses the theory of electric circuit as its operating principle. The ions and electros in the chamber of the detector move between two electrodes, thus creating an electric current. However, during a fire outbreak, smoke particles attach themselves to the ions and the current ceases to flow. Once this happens, the sensor is tripped and the home owner alerted.

photoelectric-smoke-detectorIn the photoelectric or optical detector, a beam of infrared or ultraviolet light is emitted and reflected back. If the intensity of the light reflected back is lesser than the light emitted, due to smoke or other air-borne substances absorbing part of it, the smoke sensor is tripped and the alarm alerts the owner.

Comparisons Between Optical and Ionization Smoke Detectors

1. The ionization smoke detector is cheaper than its optical counterpart.

2. Ionization smoke detectors are more prone to false alarms than the optical ones.

3. Optical smoke detectors are more responsive to smoldering fires than blazing flames, while ionization smoke detectors respond faster to blazing 4. The optical smoke detector is more reliable for detecting smoke at both the smoldering and flaming stages of fires.

5. Optical smoke detectors are less likely to be mistakenly deactivated by the home owner.

On the whole, fire safety experts and authorities advise home occupants to purchase optical (photoelectric) detectors, as they are more effective than the ionization detectors. Combination detectors that use both the ionization and photoelectric processes are also recommended.

Smoke detectors should be installed in every bedroom and hallway. They should not be placed in the bathrooms, toilets, kitchens, laundry room and the garage. One smoke detector is sufficient for each room, as long as the room’s area is less than 100m 2 . Once the area of the room is equal to or greater than 100m 2 , then two smoke detectors are placed in the room.

What Are Heat Detectors?

These are devices that detect or sense a change in temperature in a space and alert the concerned parties. Heat detectors are placed in rooms or spaces where there would naturally be smoke or mist, such as kitchens, enclosed car parks, bathrooms and toilets, laundry rooms, garages and generator houses.

For ideal residential fire protection, the combination of smoke and heat detectors is recommended.

Embedded Systems and How They Are Taking over the World

In simple terms, embedded systems are computer systems ’embedded’, planted or enclosed within a larger system for the purpose of carrying out some specific functions. Embedded systems control many devices commonly used today.

Key Features of Embedded Systems

1. Embedded systems are designed to accomplish a specific task.

2. They are characterized by small size, low cost, low power consumption, impressive operating ranges etc.

3. On the negative side, embedded systems are more difficult to program and interact with.

4. The main components of embedded systems are microcontrollers and microprocessors. Microcontrollers are processing units with integrated memory while microprocessors are processing units with external memory. Microcontrollers are used in applications where a general computer would be too costly.

5. Embedded systems could be simple, e.g. a single microcontroller chip, or complex, e.g. an enclosure of multiple units, peripherals and network mounted inside a large vessel.

6. Embedded systems are not standalone devices. For the most part, they consist of small units within a larger device serving a more general purpose.

Uses of Embedded Systems

1. The existence of embedded systems within a product helps to reduce the size and cost of the product. It also increases its reliability and performance. 2. Embedded systems provide products with flexibility, distinct features and flexibility.

3. They are typically designed to meet the requirements for real time systems. A real time system is a system which is dictated by the environment.

4. Embedded systems can be found in almost all sectors of the economy; residential, industrial, telecommunications, transportation, medical sectors etc.

Applications of Embedded Systems

Consumer and Household Applications
Mobile phones, audio players, video game pads or consoles, digital cameras, DVD players, washing machines, microwave ovens and dishwashers employ embedded systems. Home automation systems use embedded devices for sensing and controlling.

Industrial Applications

Several electric motors used in industries use electronic motor controllers, e.g. brushless DC motors and induction motors.

Telecommunications Applications

Switches, routers and bridges used in telecommunications stations are made up of numerous embedded systems.

Transportation Applications

Transportation systems, e.g. automobiles and airplanes, electric and hybrid vehicles use embedded systems to reduce pollution and maximize efficiency. Check this used car dealerships surrey.

Medical Applications

Embedded systems within medical equipment such as the electronic stethoscope are used for amplifying sounds, monitoring vital signs, and imaging or scans for internal inspection.

The term ’embedded’ rightly reflects the fact that these systems are an integral part of the general system in which they are found. It is obvious from the applications that embedded systems are almost everywhere. Gradually, they have seeped into every area of human life, from the watches we wear on our wrists every day, the printers used in our homes and offices, to the GPS devices in our cars and mobile phones. The embedded systems have taken over the world. But they are welcome to do so, and even more. Imagine life without these integral systems: Dreary, frightfully dull, uncomfortable and basically, uninhabitable.

Embedded systems provide us with the ability to communicate with one another, travel anywhere we want, and beat our friends in video games after a hard day at work. So, yes, embedded systems have taken over the word, but we are all the more grateful for it.