Don't be Confused by Wireless Home Security Systems

Don't be Confused by Wireless Home Security Systems
by: Sam Ellis

With all of the different home security system services out there, it can be hard to tell if you should have a wireless home security system, hardwired system, or a gadget that has been newly placed on the market. The goal is to stay one step ahead of any potential predators while keeping an affordable means of home security and choosing from masses of options. Recently, the best in home security has seemed to be the wireless home security system. Protecting your home from potential harm is a priority, but when you purchase a wireless home security system, you should know that there is more to the system than just the name.

The wireless home security system is primarily chosen because of its neat appearance and lack of wires. It is convenient to every abode in every situation. However, which system you choose will depend on how much security you need and what your budget entails. The best in home security wireless systems, and the most frequently used are the wireless security cameras, the wireless alarms, and the wireless motion detector systems.

The wireless cameras are a small and practical way to monitor your home security without an alarm. The cameras can be used for surveillance and the leaders in home security typically make them such as Ademco, DSC, and GE. They can be used to monitor children while playing as well as catching a common thief. These cameras have the option to record so that you may check the tapes later using a simple VCR or they can broadcast live. The wireless security cameras are generally considered the best in home security and when they are combined with other wireless devices, they are found to be almost foolproof.

The wireless alarms are the most common devices that are used. They are manual devices with a keypad that you can physically control and set. However, alarms have started to lose their credibility due to the fact that they have a tendency to go off unnecessarily causing a false sense of trust with people who have purchased them. Wireless alarms can be found anywhere from Home Depot to the Internet. Depending on what model you choose any handyman can easily install it. Visonic Powermax is a system that comes in an all-in-one pack and it also has voice activation. The Visonic model can be found on the home security store website.

The wireless motion detector system is also a common form of home security systems. The motion detectors are almost always installed into new homes, and they perform by providing a light when there is a motion that is detected. Other wireless systems may have an alarm that is attached to the motion detector, but they are harder to find. If you have other devices that are wireless that you want to use in conjunction with the motion detector such as the wireless security camera, you can move and install all of the wireless components together. If you have a hardwired system, the motion detectors do come in the wired form as well. Home security prices will vary if you go outside an already existing system.

A wireless home security system is a convenient choice because of its mobility and easy installation. There is no need to be concerned about lingering wires or expensive construction. Wireless systems do make up an entire group of elements that come together in order to create the whole. If what you are looking for is a home monitoring security system, you may not need the other devices to make sure that you feel safe in your home. Try to compile all of the information that you can in regard to the different devices that wireless has to offer so that you can make a more comprehensive choice when it comes to your home protection.

Ultrasonic Detectors

Ultrasonic Detectors
by: James Morgan

Let's cover ultrasonic detectors. The term ultrasonic denotes sound frequencies that are above the range of human hearing, the upper limit of which is 16 kHz in healthy people in their twenties. The frequencies used in ultrasonic detectors vary between different models, ranging from 23 to 40 kHz. The frequency is generated by an electronic oscillator and is fed to one or more loudspeakers. These need to be very small, smaller in fact than the tweeter in a hi-fi loudspeaker, because the moving parts must move very rapidly and so their mass must be kept to a minimum. This is an advantage of an ultrasonic detector alarm system as the units can then be made small and unobtrusive. The same unit contains a microphone with amplifying and processing circuits.

Ultra-high frequency sound is thus projected into the protected area of the ultrasonic detector. Some of it is received directly by the microphone from the loudspeaker, while some is picked up after being reflected from walls and objects in the room. When there is no movement, both direct and reflected sounds are of the same frequency. Should movement of an object occur, the sound reflected from it will undergo a change of frequency owing to the Doppler Effect. Thus the ultrasonic detector microphone now picks up two frequencies: the original received directly from the loudspeaker, and the shifted frequency reflected from the moving object.

If two different frequencies are mixed, the result is that a third one appears that is the difference between the two. When the two frequencies are close, the third is often termed a beat note. The effect can sometimes be heard when two internal combustion engines are idling at slightly different speeds: the beat note is heard by the ultrasonic detector as a throbbing sound that varies in frequency as the speed of one or other of the engines changes.

The processing circuits in the ultrasonic detector detect the presence of the beat note and actuate the output relay which is of normally closed type. The ultrasonic detector can thus be connected into a normal loop, but it is preferable for space detectors to be connected to a separate zone from the perimeter sensors so that rapid identification of the alarm source can be made. A power supply of 25 - 50 mA is required from the control box.

Ultrasonic detectors usually have a range up to 30ft, but they have a sensitivity control which can reduce the range down to about 10 ft. The polar pattern is in the form of a narrow lobe and so the device affords little protection at the sides. It should therefore be pointed towards the expected point of entry. As the Doppler Effect is greatest for forward or backward motion, the sensor is more sensitive to these than to side-to-side movements. This is another reason to mount the ultrasonic detector facing the possible point of entry.