Wireless Cameras

Choosing a wireless camera can be a daunting task unless you understand a few basics. There are so many brands with long lists of specifications out in the market. What suits you best? What doesn’t?
Before you can decide on a certain product, you need to raise a few questions first.

° Is it a colour or B/W camera?
° Is the camera technology CCD or CMOS?
° Is it a multi-channel camera system?
° Has the camera “night vision” capability? How far  the camera can see?
° How wide is the range of wireless operation?
° Is it mains-powered and/or rechargeable battery powered?
° Is it suitable for indoor operation or outdoor operation?
° Is it bundled with a DVR (digital video recorder) or a plain receiver? 
° Does it have the ability to start recording on motion detection? 
° Is it possible to connect the DVR / receiver with a computer (via USB) to view images or clips?

The first question is not really relevant in the context of wireless cameras, as wireless camera are almost always colour cameras. Black and white cameras do exist in wired regimen – most probably owing to historical reasons. I still advise you to ensure  that camera has colours.

The quality of camera image is usually dictated by the camera manufacturing technology. In simple terms, CMOS technology produces inferior images when compared to CCD technology. However, for most security & surveillance applications, CMOS cameras can be used without much loss in captured image’s detail.

A multi-channel receiver can be useful if you need to set up a number of monitoring cameras. For example, a four channel receiver can accept four camera signals in theory. In practice, it is possible that you only have a single channel available – the three channel being occupied by other wireless devices present in the vicinity. In the worst case scenario, it is possible that you dont have any channel available for the wireless camera.

That can be a big disappointment but you better acknowledge the fact, especially, if you live in a big city downtown area, where huge wireless activity is very much expected.
The receiver processes one channel at a time and scans through all the channels automatically or manually. Wireless receivers do exist, though somewhat expensive, that can process all available channels simultaneously.

A multi-channel receiver comes to rescue when there exists electromagnetic interference on one or more channels.
In such cases, you can choose the channel where the noise levels are low or non-existent. Obviously, in this case, the number of cameras that can be connected to receiver is limited to the number of noise-free channels available.

Unless you are using a camera for day-time monitoring only, you should be looking for one that can see in the dark. Infra-red LEDs are used to illuminate the scene. The range and quality of image is determined by the number of infra-red LEDs. As a rule of thumb, 20 or more IR LEDs can pick a good image with reasonable detail up to a distance of 10 to 15 meters. For surveillance purposes, even 12 IR LEDs may provide good-enough image if a range of 5 meters is acceptable.       

An open field range of 100 meters is specified for most wireless cameras, which translates to 20 to 30 meters indoor range, depending upon the number of obstacles/walls in the household. For most households this range is good-enough. It is possible to order for extended range receivers in some cases. The technique employed is to make use of high gain antennas or wireless repeaters. European regulatory laws do not permit emmisive power beyond a certain level, thus restricting the range of communication up to a nominal 100 meters.  

In order to power both camera and the receiver / DVR, mains power adapters are supplied. However, a few cameras can operate on rechargeable batteries (that is, both receivers and cameras). If you choose to buy a battery operated device, read carefully – how long does the battery last before it needs recharging? Does it really fit your application?

Another important consideration is to decide if you want to install your camera indoor our outdoor. For outdoor deployment, you need cameras with special housing. These cameras are somewhat expensive, but can withstand rain and sunshine thanks to the protective cover.

If you need to store the images or clips, which is usually the case, you must look for a receiver with a built-in digital video recorder (DVR). Inclusion of a DVR in the camera system renders the unit’s price go up, but it is well worth it. Without DVR, you can monitor image or video only in real time or else you ‘ll need to connect the receiver with a computer using a USB connection. Not all receivers are supplied with USB connectivity – if your storage medium is your computer’s hard-disk, make sure you get the receiver with USB connection. In case, all you want to know is “who is in front of the door?”, you don’t need a DVR – but you would certainly need a monitor or TV.

One desirable feature in any wireless camera product is motion detection. If this feature is present, the camera starts recording as soon as a physical object moves within the field of view. It stops recording after it detects no physical activity in the field of view.  This feature can save you from recording the static footage if you have installed the camera for security reasons. In turn you save memory space, as only motion-activated events are recorded. Motion detection is usually performed by the software. Robust wireless camera systems may employ PIR sensors for definitive event capture. 

Your home TV is your image / video viewing gadget by default. However, you can also use your PC monitor for this purpose. Wireless camera systems that include a DVR, usually employ SD card or USB stick as storage medium. Thus, it is easy to remove the SD card or USB stick from the DVR, insert it into your PC and view images or video clips on your PC monitor. If you have a wireless camera system without DVR, and if you want to be able to view  images on PC monitor (and / or save images on hard disk), you must choose a receiver with USB connectivity.     
To sum up, you must consider your requirements against options available in a certain wireless camera. You need to find (at least) a match here. More features are better but don’t pay too much for the features that you really don’t need now. 
 


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This entry was posted Thursday, April 1st, 2010 at 9:06 pm and is filed under Wireless Cameras - Articles. Both comments and pings are currently closed.