Monday, April 30, 2012

Designing of a CCTV System

Designing a CCTV System

Design Requirements
Before any camera, lens, cable or monitor is selected for a CCTV application, a designer must ask three basic questions:
What is the system's function — what is it being designed to accomplish, and will the system be integrated into other systems, i.e. access control system?
Who will manage the system and how?
Is the system new, or is it an upgrade (retrofit) of an existing system?
We will address each of these below.
1. System Function
2. System Management
3. Designing a CCTV System

System Function
Its depends some things like, "depending on the specific purpose of the CCTV system."Determining that purpose is a crucial component of the initial phase of designing any CCTV system.
There's a familiar saying among designers: Form follows function — that is, the form something takes is shaped by its purpose and usage. This form of a CCTV system —
the specific camera and lenses selected,
the mounts and enclosures,
the transmission mediums used,
the monitors, switching devices and recorders
 — all depends on the system's function. In the world of CCTV security systems, there are three basic functions, based upon what the customer wants to see:
detection (alert operator that something is happening)
recognition (allow operator to determine what is happening)
identification (show operator who is involved)

As you can see, there is a priority to these three functions. Detection is the least demanding, recognition is more demanding, and identification places the most demands on the system and the operators. It is not surprising, then, that the design criteria are similarly prioritized. In systems (or subsystems) with detection as the primary focus, there are low design criteria, that is, the demands on the equipment are not as great. Recognition is said to have medium design criteria.
Identification — seeing someone "up close and personal" — requires high design criteria.

System Function
Suppose a designer is planning a CCTV installation at a bank. Security personnel must be able to observe several areas, among them: the entrance, the lobby area, and the teller windows. At the entrance, operators simply want to know that someone is coming into the building (detection). For the purposes of this example, a camera with a fixed focal length lens viewable on a monitor is all that is needed (low design criteria). Once in the lobby area, the operators will want to determine where the subjects are, and what they are doing (recognition). A camera equipped with a remote positioning device and medium range zoom lens is required (medium designer criteria).

Finally, at the teller's windows, it is essential for security personnel to positively identify the subjects (identification). Here the requirement is for an overt, in plain view subsystem which includes a lens with high magnification, attached to a camera with remote control, carefully positioned to afford a uninterrupted view of the subject in even, adequate lighting (high design criteria).
(Note: the Federal Bank Security Act requires teller windows to have a fixed camera, in plain view that captures the teller and person at the teller window.)
In addition to the items presented in the example, the design criteria will evolve to include specifications for monitors. A small monochrome monitor may be sufficient for detection, but a large color monitor with good resolution may be the ideal for identification.

System Management
As a designer begins the task of planning a CCTV system, several policy and personnel issues come into play. Asking the right questions (and getting the right answers) as well as guiding the customer, will help identify the policies and personnel requirements for the system which, in turn, helps define system parameters.
These questions include:
Who will operate the system?
What are the criteria for controlling the system?
What are the recording criteria?
Why are they recordings being made?
How long will the recordings are archived?
What do you want to see and for what purpose?
What limitations do you have, legal and financial?

The answers to the above questions can ensure the recommended CCTV system meets important operating criteria for the customer.
Who will operate the system: Will the operators be direct company-hired personnel or contractor-supplied?
Historically, contractor personnel tend to change more often than company staff members. Experience suggests that company personnel — with greater longevity on the job — can generally handle more complexity in a system than contract workers.

The response to the first questions impacts on the answer to the second question: what are the criteria for controlling the system? CCTV system controls can be fully automatic (computer based operation with programmed sequencing of camera activity, etc.); completely operator-controlled (manual switching, directing outputs, etc.); or a combination of the two. The skill levels of operators may suggest the optimum level of automation for the system.

Now we shift to policy issues. What are the recording criteria? For example, is real time recording of event critical? How about time-lapse recording? Will video be multiplexed? Do you need a demultiplexer for individual camera viewing? If you signal is exposed to potential outside interception, do you want the signal to be recorded to be encoded and then decoded for playback control? Is there a requirement to store images on computer disk as well as video tape?

Why are the recordings being made? Are images being stored simply for administrative purposes — for use by company personnel only? Or will the stored images possibly be used as evidence in possibly litigation?
Finally, how long will the recordings are archived? Long term archiving suggests the need for a storage area which has environmental controls to preserve the tape (as well as space enough to contain the volume of tapes accumulated over the years). Answers to these questions will impact on the type of equipment selected and even the basic design of the system infrastructure.

Designing a CCTV System

New Construction or Retrofit:
Designing a CCTV system can be a lot like house construction. It is often easier to design and proceed with all new construction instead of integrating new components into existing systems. Whether the project is new construction or upgrading (retrofitting) an existing system, several fundamental issues must be addressed prior to the installation process. Answers to the following questions will provide valuable information:
Will other systems (e.g., access control) be integrated with the CCTV System?
What transmission mediums will be used?
What is the project budget? Has it been planned, committed and
What are future system requirements regarding upgrades?
Will application requirements change in the future?

Each of these questions helps the designer to define a system that meets the customer’s needs for the present and the future.
Will the CCTV system be integrated with other systems? Will the CCTV system need to supply information regarding access control or other systems? What level of integration is required? If there is an existing CCTV system, are there component compatibility issues that must be addressed? What is the most efficient and cost-effective transmission medium for the system? If an existing CCTV system is being upgraded or supplemented, what is the existing transmission medium, and should the upgrade include changes to the existing transmission medium? What is the project budget? In a sense, the answer to this question can define many of the design elements for a CCTV project. There are obviously many ways to proceed while satisfying any budgetary restrictions. The basic options are to reduce the number of components (and therefore coverage) or use components with fewer capabilities or lower quality, e.g., monochrome cameras instead of color, or a camera with generally lower specs (resolution, sensitivity, S/N) as long as the component will still provide the performance required for the application. Also, how was the budget determined? Is it based on sound preliminary research or a "guesstimate?" Have the decision makers committed to it and has it been approved? Does the option exist to review the budget or is the designer locked into the approved amount?
Designing a New System
What are the requirements for future upgrades? As newer technologies become available, is the customer's expectation that these will be incorporated into the system design. Is there a planned migration path to accomplish this?
Related to this last question is another: will application requirements be changed in the future? Will enhanced functionality be required at a later date? That is, will the function of the CCTV surveillance system or the overall security system change in the future?
For example, is the company planning to expand its facilities locally or even remotely? Consider a commercial laboratory that is planning to move into new markets within the next five years. The new business will demand new levels of access control and CCTV coverage. Being aware of that future requirement can impact decisions regarding the current decision. Answers to all of the above questions sets a baseline for CCTV system design. These are primary issues. Secondary issues are the "nuts and bolts" aspects of system design, and careful attention to these primary questions will automatically define many of the hardware issues.

A carefully designed CCTV surveillance system will ensure:
  1. adequate coverage
  2. Extendability for future additions and enhancements.
  3. Satisfied customers.
Installation Tools & Techniques
All cameras need to be powered and have a way to get the video signal back to the monitor and recorder. The most reliable way to achieve this is to "hardwire" your camera system. Some camera locations may require wireless transmission of the video signal but you should avoid using wireless if possible. Wireless is best suited for temporary surveillance applications.
Video/power cable can be purchase pre-made in specific lengths like 25m, 50m etc. It can also be purchased in bulk rolls of 500m or 1000m that can be made to custom lengths.


You may also have excess wire to deal with. This is especially bad when it's on the monitor end. Making custom cables makes for a neater installation and costs less per foot/ meter.

If you decide to make your own cables you will need some specialized tools. One is a wire stripper, the other is a crimper. You will use these to prepare your cable for "BNC" connectors. Using these industry standard connectors will insure that your wiring is compatible with most cameras on the market. It also allows you to replace or upgrade your cameras at a later date with out having to rewire your system.

Most installations require that you hide your wiring as much as possible. You can do so by "fishing" the wire through your walls & ceilings. We first drill a 3/4 inch hole in the top wall plate as well as where you will be mounting the camera.

This size hole will allow you to use the pre-made cables or the custom made cables. We insert small flexible fiberglass rods into one hole and try to push it out the other end.
They come in 6' lengths and can be combined with other rods. This is especially helpful when pulling wire over long distances like a drop ceiling.
Once the rod is sticking out the other end, attach your video cable to it and pull the wire out until about 18" is sticking out. You'll have plenty of wire to work with.
Another type of wall fishing tool is called a fish tape. It is a long metal wire that is wrapping onto a spool. You simply pull out a small amount and feed it into your hole. Keep pulling and feeding it until you can attach your video cable to it.

Individual transformers or a power distribution panel can power you camera system. For neater installations especially for systems with more than 4 cameras use a power distribution panel. A power strip with 8 outlets fills up rather quickly when you also plug in the monitor, recorder and 4 transformers.

Monday, April 23, 2012

Why Solar ?

In the long term, solar energy is the best answer to the greenhouse effect. Solar energy is CO2 free and virtually inexhaustible. According to the International Energy Agency (IEA), at present, solar energy constitutes a mere 0.04% of worldwide energy consumption whereas fossil fuels feed over 80% of the world energy supply. However, some key facts on solar energy highlight its significant potential:
  • Two billion people in the world have no access to electricity. For most of them, solar energy would be their cheapest electricity source, but they cannot afford it.
  • In just one hour, the Earth receives more energy from the sun than human beings consume during an entire year.
  • According to America's Department of Energy, solar panels could, if placed on about 0.5% of USA’s mainland landmass, provide for all of its current electricity needs.
In addition to the dramatic benefits to reducing global warming, harnessing solar power can reap significant benefits for individuals and businesses alike. For example, businesses can use solar energy to:
  • Reduce the risk and cost of power outages and backup power systems.
  • Strengthen relationships with key stakeholders such as customers and the community, by demonstrating sensitivity to climate change issues.
Solar panels absorb sunlight through their silicon membrane and turn the energy absorbed into useable power.


Photovoltaic Cells: Converting Photons to Electrons

The solar cells that you see on calculators and satellites are photovoltaic cells or modules (modules are simply a group of cells electrically connected and packaged in one frame). Photovoltaic’s, as the word implies (photo = light, voltaic = electricity), convert sunlight directly into electricity. Once used almost exclusively in space, Photovoltaic’s are used more and more in less exotic ways. They could even power your house.

How do these devices work?



How Silicon Makes a Solar Cell



Anatomy of a Solar Cell

Solar energy is renewable energy for humans. It's also clean energy, do not generate any environmental pollution. Solar photovoltaic (PV) was the most watched item in the researching of solar energy utilize.
Solar PV Panel
1, silicon solar cells; 
3, polymer materials solar cells; 
4, nano-crystalline solar cells. 


1.Silicon solar cells
Silicon solar cell's structure and working principle,
Solar Cell
 As shown in the picture, 
positive charge(+) means silicon atom, 
negtive charge(-) means electron around the silicon atom.

A hole will exist in the crystalline silicon when the 
cyrstalline silicon mixed with boron, 

it's shape as below picture:

Silicon Crystalline



yellow means Phosphor atom, the red means superfluous electron.





2. Crystalline silicon solar cell manufacturing process.

Chemical vapor deposition mainly the SiH2Cl2, SiHCl3, SiCl4 or SiH4, as the reaction gas, It's react at a certain protection atmosphere and deposit silicon atoms at the heated substrate, the general substrate materials are Si, SiO2, Si3N4, etc.. But the researching found that it's difficult to form the large crystal on the amorphous silicon (a-si) substrates and easy to cause interspace between crystal. Solutions for this problem is to deposited a thin layer of amorphous silicon on the substrate by LPCVD, then annealing this layer of amorphous silicon, to get larger crystal, and then deposited a more thick poly-crystalline silicon film at this layer, therefore, re-crystallization technology is no doubt a very important aspect, the current technology used is solid-phase crystallization and recrystallization in the FZ method. Poly-silicon thin-film solar cells not onlyi use the re-crystallization process, also used almost all of the mono-crystalline silicon solar cells preparation technology, the solar cells made by this way have a remarkably increased it's conversion efficiency.

3. Nanocrystalline chemistry solar cell
Silicon solar cells are undoubtedly the most sophisticated atom all solar cells, but because of its high cost, can not meet the requirements of large-scale application. Therefore, Peoples always explore in process, new material and thin film solar cells etc, among this, the newly developed nano TiO2 crystalline chemistry solar cells get a great importance from home and abroad scientists.
For example, the dye-sensitized nano-crystalline solar cell (DSSCs), such solar cells mainly includes a glass substrate deposited with trasparent conductive film, dye-sensitized semiconductor materials, electrode and electrolyte etc.


Cathode: TCO glass deposted with platinic
Electrolyte: I3-/I-

How do solar panels work?
Solar CCTV System




Energy Loss in a Solar Cell
Speed Dome with Solar


Wednesday, April 18, 2012

Stand-Alone Power System Design Procedure for CCTV System

What would you have to do to power your equipment with solar energy? Although it's not as simple as just slapping some modules on your equipment, it's not extremely difficult to do either, but will require calculations.


If you have a location with an un-shaded, south-facing orientation, you need to decide what size system you need. This is complicated by the facts that your electricity production depends on the weather, which is never completely predictable, and that your electricity demand will also vary.

These hurdles are fairly easy to clear. Meteorological data gives average monthly sunlight levels for different geographical areas. This takes into account rainfall and cloudy days, as well as altitude, humidity, and other more subtle factors. You should design for the worst month, so that you'll have enough electricity all year. With that data, and knowing your equipments power requirement (you must add together the power requirements of all equipment you intend to power with your solar system), there are simple methods you can use to determine just how many PV modules you'll need. You'll also need to decide on a system voltage, which you can control by deciding how many modules to wire in series.


Solving Solar-power Issues in CCTV

Certainly, no one would accept only having electricity during the day, and then only on clear days, if they have a choice. We need energy storage; this is accomplished with a battery storage solution. Even though batteries add ongoing cost and maintenance to the solar system, if you are in a remote area you won’t have a choice but to use them. Solar in a CCTV application is usually last resort. One way around the problem is to connect the charging system to the utility grid, charging the batteries to full capacity so when there is no power available the system will run off the batteries and you won’t have to worry about your system shutting down. An example of this would be a CCTV system to be installed in a parking lot with existing power standards / light poles / electricity poles, where utility power is only supplied during the dark hours and turned off during the day.

you decide to use batteries, keep in mind that they will have to be maintained, and then replaced after a certain number of years usually 5 years is the typical battery life, but newer technologies are always being invented. The PV modules should last 20 years or more, but batteries just don't have that kind of useful life. Batteries in PV systems can also be dangerous because of the energy they store and the acidic electrolytes they contain, so you'll need a well-ventilated, non-metallic enclosure for them.

The most commonly used deep-cycle batteries in CCTV solar systems are Glass mat or GEL batteries. Deep-cycle lead-acid batteries can't be discharged 100 percent without seriously shortening battery life, and generally, PV systems are designed to discharge lead-acid batteries no more than 40 % or 50 %.

The other problem besides energy storage is that the electricity generated by your PV modules, and extracted from your batteries may not be in the correct form; depending on what you equipment uses AC or DC voltage you will have to add additional components to change the voltage to the correct one. You will also need to consider the converters power loss and calculate that into the total power draw of the end solution so you have enough to power everything.


Now come how to design the CCTV Power system:

This example deals with the design of a stand-alone PV system for powering a remote CCTV transmission system.
Tare a few steps that need to be taken when designing a stand-alone system and we recommend the following:
1. Determine the Load
LOAD: - CCTV camera. It draws an average of 25W for 24 Hrs per day at 24V DC. The current draw is 2.09A.
- Load calculation can be down in two ways: either calculated on a daily basis or weekly. Regardless of which you choose you need to be as accurate as possible.
1.Decide Battery Storage
To be able to handle the CCTV load and allowing for 5 days of battery storage, we require a battery capacity of:
Battery Storage is usually expressed in Amp hours. However, it can be given in Watt hours.
For the above load the battery storage (Ah) would be calculated as: 2.09 A x 24 h x 5 days = 250.8 Ah
  • Watt-Hours = Volts x Amphours
  • Example: 12V @ 250.8Ah = 12 x 250.8 = 3009 Watt hours or (3.9kWh)
Approximation of Array Size - If the system is going to be used all year round and the energy requirement is fairly constant then the design month will be December or January, that is when the weather is at its worst.
Array Size (Wp) = Daily energy requirement in Watt Hours [Wp] / Average Daily PEAK SUN HOURS in the design month / System Effeciency.
Array Size = [25W x 24h] / 2.5 / 0.65
Array Size [Wp] = 600Wh / 2.5 / 0.65 = 369.2Wp

Monday, April 16, 2012

Wireless CCTV – Connecting a Burglar Alarm System

Wireless CCTV cameras or IP cameras are the digital replacement for traditional CCTV, but the technology is sophisticated and there is a lot more you can do other than looking at your home or business from across the internet.  For example, you can connect these cameras to most good burglar alarm systems, so that when a camera detects movement, the alarm system will trigger.  You can also set up your cameras so that when the burglar alarm is tripped, you will get an instant text message on your phone.  These amazing new features can bring many an old alarm system into the 21st century without the cost of replacing it and here in part one of this two-part series, I’m going to look at the things you will need in order to achieve this.

The first thing you need is a wireless internet CCTV camera that has a digital I/O port and an alarm system that has a spare digital I/O port too.  Incidentally, this is just a technical name for a little block of connectors where wires can be attached.  Most serious wireless CCTV cameras have such a port.  If your alarm system has one of these ports, it will be inside the alarm control box.  Not all systems have this, but many do – just take a look in the manual.  If you no longer have a paper copy of the manual, search the support section of the system manufacturer’s website where you can often find an electronic copy.

Having verified that your camera and alarm box has digital I/O ports, you will also need to check a few other things in the alarm system manual and the camera manual.  (If you have not yet bought the camera, find an on-line copy of the manual to carry out these checks before you spend your money.)  First of all, check the voltage and power specifications of the camera’s output port and the alarm’s input port.  Do the same check on the camera’s input port and the alarm system’s output port.  Basically, you need to make sure that there is a match, but it is true to say that most wireless internet CCTV camera ports are designed to work with most alarm system ports.  Next, find the precise connectors that you need to use within the connection block that makes up the port, both on the camera and the alarm box.  The next thing you will need is a length of alarm cable to reach from the camera to the alarm control box.  This cable will typically have at least four strands, but if you can only get eight core or whatever, no problem, we’ll just be using four of the wires for this task.

Once you have reached this stage, you will want to know how to connect everything up, which I will look at in part two of this series, not to mention how to configure the alarm system and camera to make everything work, which I will describe in part three.

Now we find out how to connect the wiring from the I/O port of your camera to the I/O port in your alarm box.

The physical connection is very easy.  First let’s look at the alarm box.  You will need to remove the cover, but make sure that any anti-tamper mechanism is switched off first!  Choose the best point for the wire to pass through the box wall – there are usually a number of pressed potential openings marked on the casing and the one you choose will depend on where the box is situated.  Pass the end of the cable through the opening into the alarm box, then connect two strands to the digital input connectors of the port, and two strands to the output connectors.

Next you will need to run the wiring to the camera and connect it up.  It is always best if you can place the wiring where it will not get trodden on, as this may in time break the strands.  You also need to consider possible tampering.  If this wire is cut, your home security system will still work, as will your wireless CCTV camera, but they will not work together which is our objective here.  Therefore it is best if the wiring is hidden within a stud wall or a ceiling, if this is at all possible. Bringing the wiring to the alarm box from the wall behind it is also a very good idea if you can manage it, as this makes it practically inaccessible to intruders.

The final part of the physical installation is the wireless CCTV camera end.  Find the output connectors of the I/O port, and connect the same coloured strands that you connected to the alarm box input connectors.  Make sure you re-check the manuals to be certain of connecting the wires the right way round; it makes a difference and if you get it wrong you could damage your wireless CCTV equipment.  Similarly, take the strands that you connected to the alarm’s output connectors and join these to the camera’s inputs, again making sure you get them the right way round.

Having connected the wiring, you are ready to configure the alarm box and wireless CCTV camera to make everything work.  Have your camera manual and your alarm system manual at the ready, and then take a look at the final part in this series, part three, to find out how to achieve this.

Now in this part of the series you will find out how to configure everything to turn your old burglar alarm system into a state-of-the-art home security system for the 21st century.

Check your alarm system manual to see if you need to do any re-programming of the box, or moving of dip switches or so-called “jumpers” (connectors between two points that can be moved to change a system’s functionality).  You want to make sure that when your camera sends an alarm signal to the input port of the alarm box (when it detects movement), it causes the alarm system to trigger.  You also want to make the burglar alarm activate its digital output port and thereby inform the camera when the alarm system is triggered.

At the camera end, check the camera manual to find out how to configure an event action so that when the camera detects movement, it sends a signal down the cable to the alarm box.  Once you have this set up, when your cameras detects movement, your burglar alarm will go off.  Now make sure the opposite end of the equation works.  The aim is that when the burglar alarm triggers and sends a pulse to the camera’s input port, the camera will send a text message to your phone and record images of the scene.  Configure the camera so that it will trigger when its input port is activated.  If you haven’t the time or inclination to do all this yourself, you may prefer to buy a ready-configured camera pack from a wireless CCTV specialist.

When you use wireless CCTV cameras to trigger an alarm system in this way, there are a few safeguards that you need to build in.  These cameras are very sensitive to changes in the picture, and may not always be able to differentiate between a change in light levels, such as a street light coming on outside your home or the sun moving behind a cloud, and an intruder.  For this reason it is very important only to use a camera in this way where there is no possibility of a change in natural or artificial light within the camera’s field of vision.  An internal hallway or corridor would be a good location, as any change in the image here would likely require an intruder.

The payback for going through the process of integrating a wireless CCTV camera with your alarm system in this way is that you will end up with a much more effective and useful home security system.  Firstly, it will be able to “see” through the lens of the camera.  Secondly, instead of just ringing an alarm bell on the side of the property, the system will advise you almost instantly of any alarm by sending a text message to your mobile phone, using the functionality of the camera.  This means that you can log in over the internet from wherever you are and see what is going on.  Finally, you will also be able to review the incident that caused the alarm, by looking at images that the camera will have recorded.  You can do all of this within moments of the incident and alert the emergency services who will take you very seriously indeed when you tell them you have actually seen the intruders!

By adding a wireless internet CCTV camera to your alarm system you can achieve peace of mind on a different level.  You will know that if your camera detects movement, your burglar alarm will sound.  You will know that if your burglar alarm is triggered, you will get an instant text message and be able to take a look at what is going on, from wherever you happen to be.  This really can bring the average alarm system into the 21st century without the cost of replacing it.

You can used this article in wire based system.

Thursday, April 5, 2012

Wireless Security Cameras – Pros and Cons

Increasing security concerns have led to increasing numbers of security cameras. Public buildings, stores, banks and private homes have all stepped up the security of their property and installed video cameras. Now, technology has made it easier than ever to look after your property. Low voltage wireless security cameras are the most popular security devices in today’s environment. They offer a number of choices that can meet different security needs. While they offer significant advantages, there are certain disadvantages attached to these cameras as well. It is important to understand both these aspects before taking a decision.

Pros of Using Wireless Security Cameras

1)    No wiring – The absence of wires make wireless security cameras a preferable choice over wired security cameras. Wired systems are very labour intensive and the cost of installation is very high. Also wiring can damage the overall aesthetic appeal of your home decor. Hence, it is always better to go for wireless cameras.
2)    Easy to install – These security cameras are the most easy to install as they do not involve endless wiring as a pre-requisite. You can choose between battery operated cameras or you can opt for the ones that can be plugged into electric sockets. The best do-it-yourself kits come with wireless security cameras.
3)    Portable – You can move around with your home security system in case of wireless cameras. In case, you shift from your current location, the security system can be uninstalled and moved with minimal effort.
4)    Flexible – You can install these cameras even in the most remote of the locations where wiring is not possible. Location is not a constraint for wireless cameras.
5)    Variety – You can choose between varieties of cameras based on your requirements. From big security cameras to the miniature hidden cameras, all options are available in case of wireless security cameras.
Wireless CCTV

Cons of Using Wireless Cameras

1)    Disruption of Signal – Most wireless security cameras send signal through wireless routers. The signal strength can become particularly weak if such devices are installed at the outer perimeter of the signal coverage.
Also, the signals of other wireless devices like phones, wireless networks can disrupt the signals from wireless cameras. A huge obstruction like a tree can also prevent the signal from passing on. Thus, these cameras can be unreliable at times.
2)    High Maintenance – If you have selected cameras that run on batteries, you need to frequently monitor these cameras for any need to change the batteries. If you run out of power at a crucial moment, the entire security system will suffer. If you have selected cameras that run with electric power, you need to have electric sockets wherever you want to install cameras, which may not be possible for difficult to reach locations.
3)    Unsecured – The signal from wireless security cameras can easily be hacked if it is not secured properly. In this case, probable intruders can watch the coverage provided by your cameras and can find alternative places to enter the building. Also, signal can be disrupted by intelligent hackers.
As there are many pros and cons of using wireless security cameras, one must give due consideration to their requirements before making the final decision.