Appliance Control: Making Things Do Stuff - Smart Home Automation with Linux and Raspberry Pi - page 44

When a camera is located inside but pointing outward, then it is best to look for those supporting some form of
“night view mode.” Those using a CMOS sensor are better in this regard because they can work at light levels down to
0.2 lux, whereas traditional CCDs (as used in webcams) are a mere 3 lux. Most CCD cameras that claim night mode
usually implement it in software and do nothing that a good GIMP session couldn't fix, so opt for CMOS wherever
possible.
For the most part, all CCTVs will work in the same way; it's a case of balancing specification and price for your
budget. Consider the size of the images, FTP upload, web access, whether you get e-mail notifications on motion
detection, and so on.

Wireless Cameras That Aren't
Many CCTV cameras on the market use the phrase wireless in a context that does not refer to WiFi. One such device
is the XCAM2 Wireless Camera System. They actually use the industrial, scientific, and medical (ICM) wireless radio
band to transmit their signals to a customized receiver, often for display on an attached monitor. These are therefore
unsuitable for integrated home automation solutions, where the CCTV output needs to be viewed remotely.
However, if the particular receiver provides an output to RCA composite video, you can plug these into a TV
card and record from that or use a hardware media recorder such as the Emprex ME-1. This limits you to one camera
and prevents you from using the TV card (for recording or watching) while the CCTV is active. Of these, the second
problem is easily solved by buying a second TV card. The former is more difficult.
If you need multiple cameras, then you will need to employ some additional control hardware, which could push
the cost beyond that of an all-in-one IPCCTV camera. There are two approaches to the problem.
The first involves using several cameras but only one receiver. You can then use X10 to switch particular cameras
on and off as required. The receiver will pick up the (only) signal now present and pass it to the TV card as before. This
is the method suggested for the XCAM2, but it means you can't review all the cameras at a glance.
The second solution uses multiple receivers (and therefore more cost) and a TV switcher to select between the
different inputs. Some of these will even combine all images into one. Switching these units will require the use, and
programming, of a computer-based IR transmitter because most are not IP-controllable. (We'll look at IR control
later.)

Custom Hardware
In many cases, it is not necessary to build your own CCTV configurations, because it's a known problem for which
manufacturers have provided their own solutions. One such unit is a CCTV recorder/DVR, which usually comes
with a CD rewriter and video out. This box will capture the feeds from multiple cameras and provide their output
by S-video or composite, which can then be fed into a TV card, as before, for remote viewing and recording. Some
versions are also supplied with an infrared remote control and network port.
Another alternative, if you'd like to keep everything PC-based, is a PCI card for real-time surveillance that can
monitor four or more input channels from a single card, like the RW-1240R. The software and drivers for most of
these, however, are currently Windows-based, so we don't dwell on it any further.

N Many of the stand-alone CCTV devices accept camera inputs from BNC video connectors, whereas the
webcam-based ones use RCA.

Caution