science

Wireless security camera

Wireless security camera is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Wireless security camera rather than just read about it. In short: Wireless security cameras are closed-circuit television (CCTV) cameras that transmit a video and audio signal to a wireless receiver through a radio band. Many wireless security cameras require at least one cable or wire for power; "wireless" refers to the transmission of video/audio.

Key takeaways

Wireless security camera belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Wireless security camera to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Wireless security camera from memory before moving on to harder problems.

Reference excerpt

Wireless security cameras are closed-circuit television (CCTV) cameras that transmit a video and audio signal to a wireless receiver through a radio band. Many wireless security cameras require at least one cable or wire for power; "wireless" refers to the transmission of video/audio. However, some wireless security cameras are battery-powered, making the cameras truly wireless from top to bottom. Wireless cameras are proving very popular among modern security consumers due to their low installation costs (there is no need to run expensive video extension cables) and flexible mounting options; wireless cameras can be mounted/installed in locations previously unavailable to standard wired cameras. In addition to the ease of use and convenience of access, wireless security camera allows users to leverage broadband wireless internet to provide seamless video streaming over-internet.

Types

Analog wireless Analog wireless is the transmission of audio and video signals using radio frequencies. Typically, analog wireless has a transmission range of around 300 feet (91 meters) in open space; walls, doors, and furniture will reduce this range. Analog wireless is found in three frequencies: 900 MHz, 2.4 GHz, and 5.8 GHz. Currently, the majority of wireless security cameras operate on the 2.4 GHz frequency. Most household routers, cordless phones, video game controllers, and microwaves operate on the 2.4 GHz frequency and may cause interference with a wireless security camera. The main difference between 2.4 and 5 GHz frequencies is range. 900 MHz is known for its ability to penetrate through barriers like walls and vegetation.

Advantages Cost effective: the cost of individual cameras is low Multiple receivers per camera: the signal from one camera can be picked up by any receiver; you can have multiple receivers in various locations to create your wireless surveillance network

Disadvantages Susceptible to interference from other household devices, such as microwaves, cordless phones, video game controllers, and routers. No signal strength indicator: there is no visual alert (like the bars on a cellular phone) indicating the strength of your signal. Susceptible to interception: because analog wireless uses a consistent frequency, it is possible for the signals to be picked up by other receivers. One-way communication only: it is not possible for the receiver to send signals back to the camera.

Digital wireless cameras Digital wireless is the transmission of audio and video analog signals encoded as digital packets over high-bandwidth radio frequencies.

Advantages Wide transmission range—usually close to 450 feet (open space, clear line of sight between camera and receiver) High quality video and audio Two-way communication between the camera and the receiver Digital signal means you can transmit commands and functions, such as turning lights on and off You can connect multiple receivers to one recording device, such as security DVR

Uses and applications

Home security systems Wireless security cameras are becoming more and more popular in the consumer market, being a cost-effective way to have a comprehensive surveillance system installed in a home or business for an often less expensive price. Wireless cameras are also ideal for people renting homes or apartments. Since there is no need to run video extension cables through walls or ceilings (from the camera to the receiver or recording device) one does not need approval of a landlord to install a wireless security camera system. Additionally, the lack of wiring allows for less mess, avoiding damage to the look of a building. A wireless security camera is also a great option for seasonal monitoring and surveillance. For example, one can observe a pool or patio.

Barn Cameras Wireless cameras are also very useful for monitoring outbuildings as wireless signals can be sent from one building to another where it is not possible to run wires due to roads or other obstructions. One common use of these is for watching animals in a barn from a house located on the same property. One such example of this can be seen in this story of one of the first "BarnCam" in the New York Times.

Law enforcement Wireless security cameras are also used by law enforcement agencies to deter crimes. The cameras can be installed in many remote locations and the video data is transmitted through government-only wireless network. An example of this application is the deployment of hundreds of wireless security cameras by New York City Police Department on lamp posts at many streets throughout the city.

Wireless range Wireless security cameras function best when there is a clear line of sight between the camera(s) and the receiver. If digital wireless cameras are outdoors and have a clear line of sight, they typically have a range between 250 and 450 feet. If located indoors, the range can be limited to 100 to 150 feet. Cubical walls, drywall, glass, and windows generally do not degrade wireless signal strength. Brick, concrete floors, and walls degrade signal strength. Trees that are in the line of sight of the wireless camera and receiver may also impact signal strength. The signal range also depends on whether there are competing signals using the same frequency as the camera. For example, signals from cordless phones or routers may affect signal strength. When this happens, the camera image may freeze, or appear "choppy". Typically, the solution is to lock the channel that the wireless router operates on.

Illustrations

Worked examples

Example 1 — a first encounter with Wireless security camera

Start with the simplest possible case. Write down what Wireless security camera claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Wireless security camera before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Wireless security camera ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Wireless security camera

In research: Wireless security camera appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Wireless security camera in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Wireless security camera is common in secondary-school and first-year university syllabi. It links to neighbouring topics Video, Wireless, so understanding it makes those chapters shorter.
In everyday life: Look for Wireless security camera outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Wireless security camera in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Wireless security camera means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Wireless security camera out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Wireless security camera in simple terms?

Why does Wireless security camera matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Wireless security camera?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Wireless security camera.