How to add security cameras to your system
The cost of video cameras is coming down quickly. Some of these
are beginning to show up as 'toys', at under $50 and even a simple black and
white camera can be a valuable addition to your home automation system.
Whether you have worries about your baby sitter, or kids trashing your
landscape, or just want to be sure you capture pictures of an intruder, here's
You can use that old cam-corder in the closet, or you can find used
bank-security cameras in the newspapers, or the auction websites. The things
that matter most are that you can attach them to your VCR, and that they produce
a reasonably clear image.
Although this article does assume the NTSC video standard,
the ideas are the same if your country uses the PAL or SECAM
Do be careful that you make sure that the camera puts out a video signal that
can be directly fed into your VCR or TV. Some models like the Connectix QuickCam
put out 'serial data' signals which can only be used via your Printer or Modem
or USB ports.
Here's an older model CCD camera which
was used for video conferencing.
These can often be found in the want-ads for under $50.
Although color cameras are nice, the Black and White cameras are much better for
night-time surveillance. Many require only 0.5 LUX, and even a small outdoor
flood provides enough light for decent pictures.
For those with deeper pockets, you can purchase an InfraRed LED type light that
is not detectable by a human, but provides light to the B&W cameras just like a
Power and Signal Wires
It will usually be easy to get power to the camera, however it may be more
difficult to get a reasonably strong video signal back to the recorder.
The older bank style video cameras are powered directly by 110 volt house
current, and generally have fairly strong amplifiers which can transmit their
signals more than 200 feet or so. However the newer CCD cameras are powered by
12 volt wall transformers, and normally can't send signals more than about 30
In cases where the distance is too great, you will need to provide a signal
amplifier, or the recorded pictures will be all but worthless.
In some cases you may want to hide the camera, and in others you may want the
camera in plain sight. Regardless, you need to get power to the camera, and the
video signal must be brought back either to a VCR or to your computer.
Another technique is to use a wireless transmitter and receiver which can send
the video signal about 100 feet.
|The newest X-10 wireless camera.
||This transmitter will punch the signal about 100 feet.
Multiple Cameras and Switching
If you want to have multiple cameras, and don't want to buy one of the
commercial camera switchers, there are a couple of techniques for this.
In both of these techniques, we must turn off either the power to all but one
camera, or allow the video signal from only one camera at a time to be sent to
|Here we use common X-10 appliance modules to control the power to the
'wall wart' transformers which power the cameras.
This technique doesn't require that you cut any wires, but it does take a
little longer for the cameras to start up.
|Here we use X-10 Universal modules to enable/disable the signal from
each camera rather than switching the power.
With this technique you do have to cut into the video signal wires, but the
cameras are always powered up and the video signal is immediately stable
after they are switched.
The Passive Adaptors in the above images are nothing more than a simple device
that lets you plug two inputs into one output.
|Here are some adaptors which allow you to connect the common RCA type
plugs to the 'BNC' type connector which is more common with 'coaxial' type
The "Y" adaptor here allows you to connect two inputs to one output.
If you need to locate your cameras more than 100' from the TV/VCR, and can't use
the X-10 wireless transmitter, then you might consider using a simple amplifier
available from Radio Shack.
Radio Shack part number: 15-1103 lists for $29.95
Even in this case, you can have multiple cameras using the techniques above.
|I use these amplifiers for cameras that are over 300 feet away !
Although this amplifier is normally used for video and audio, I have found
that even the 'audio' inputs/outputs work for 'video' signals.
Control and Switching
You can't have two or more cameras sending signals to the TV/VCR at the same
time, or the signals will distort each other. So you have to manage them with
You may want to have one camera always ON, and always viewable on the monitor.
And whenever a motion sensor detects an intruder at the location of another
camera, you simply turn OFF the first camera and turn ON the other one.
You might want to put the Appliance/Universal modules on the same house code so
that you could simply issue one "All Units OFF" command, turning all cameras
OFF, and then turn ON just the camera you want.
Example Scripts for "Front Door Motion":
All Units OFF "C"
turn on "Front Door Camera"
All Units OFF "C"
turn on "Normal Camera"
Wireless direct to the TV
There are also some very inexpensive "RF Modulators" which take the video signal
from the camera and re-transmit on a standard TV channel. Thus you can have
multiple cameras, each on a different channel, and then you can switch to them
manually, and even use them with that fancy Picture-In-Picture feature !
Protect those outdoor Cameras
Most of the inexpensive cameras available today are not intended for 'outdoor'
locations, however I've had these cameras outside for over two years, with only
cellophane tape and aluminum foil protecting them.
One thing to remember that will help you enjoy your security cameras even more:
Place and aim your cameras so that you can both enjoy your landscape and watch
paths and driveways...!