Set Up a Video Home Security System
How many cameras you'll need, where to
put them, and how to adjust them
Video cameras can monitor
the inside and outside of your home and property, and can
automatically detect motion and send you alerts when this
Part 1 of a series about
the Logitech Alert and home security cameras in general;
please also visit
How to Best Set Up Video
Monitoring at Your Home
2. Logitech Alert 750 review 1
3. Logitech Alert 750
4. Logitech Alert 750 review 3
There was a time when the most
sophisticated home security system was a loud bell that would
ring outside your house if a window was broken or door opened,
and hopefully a neighbor would call the police.
Flash forward to the present
day. The old concept of having micro-switches on doors and
windows, plus motion sensors and pressure pads inside the house,
connected either to an external bell and/or to a remote alarm
monitoring company has now been replaced with the ability to
have an audio visual system that will directly contact you (and
any other people or monitoring companies you wish) when they
detect motion. A good place to start exploring this type
of modern sophisticated alarm system is
No more false alarms.
Simply look at the real time footage from your cameras, either
on your phone or on a computer, anywhere in the world. If
you see bad guys breaking in, call the police. If you
don't, relax and adjust your motion sensitivity!
This first part of our new
series gives you pointers on how to design and set up a home
video monitoring system. Subsequent parts review one of
the best of the current crop of home video monitoring systems,
the Logitech Alert system.
How to Best Set Up Video
Monitoring at Your Home
You don't need to have every
part of your property and home covered by a triply redundant
camera system. Just because your home
might have four bedrooms, three bathrooms, two levels and a
garage doesn't mean you need to have cameras in every room.
Neither also do you need
external cameras on all four sides of your house.
For sure, more cameras are
more fun (and more functional) than fewer cameras, but all you really need to do is to
have an essential pathway inside your home monitored, so that if
anyone is going to be coming into your home, moving around, and
then leaving again, you may get a good video clip with
a recognizable picture of the person (assuming they are not
wearing masks or hoods, etc).
A single camera
installation may be internal or external, depending on where you
think the key common point is that anyone visiting your property
will travel past. Your objective is not to film a
'documentary' showing every last detail of where an intruder
goes in your house. All you want is to get early
notification that someone is in your house, and then you call
the police and see which happens first - the burglar leaving, or
the police arriving.
A multiple camera
installation might supplement an internal view or views with an
external view or views (if you have a freestanding house) so as
to ensure you get an earlier and certain detection of any
External Camera Considerations
Most burglars or other
'guests' of dubious provenance will first go to your front/main
door and innocently knock on the door. This is a
great way for them to determine if the house is currently
occupied or not.
If there's no answer, they
know they've found a vulnerable property, but if someone comes
to the door, they'll invent an excuse - maybe they'll say
they're lost, or looking for the next house along, or pretend to
be selling you something, or who knows what.
You're sure to have had such
people at your door in the past - have you ever stopped to
wonder if they were truly who they said they were, or if they
were burglars scouting out your property and your presence?
So, an external camera
should ideally be somewhere aimed towards your front door, so as
to pick up on people when they arrive. You can even use
this while you are inside to see who is at the door - maybe it
was just a deliveryman dropping off a package and you don't need
to drop what you were doing and rush to the door.
If you want to add
additional external cameras, then you need to think about other
areas of interest or vulnerability. If you were a burglar,
how, other than down your driveway/along your apartment block
corridor would you access the property? And where, other than
through the main door, would you choose to break into the house?
Naturally, larger doors and
windows that are on-grade are much more vulnerable than upper
floor windows - ground level windows and doors are easier to
quickly go in and out, and to pass stolen items through.
Maybe you have problems with
people trespassing through your property as a short cut, or
maybe you have a pool or hot tub you want to keep an eye on.
In that case, aim cameras in those directions.
Maybe you have a problem
with parcels being stolen off your front door step. Maybe you're as concerned
with keeping an eye on what is happening around your property
with your children, your friends, and invited guests. In
all cases, set up your cameras with sight lines to the relevant
areas of vulnerability.
Think also about a second
concept. Maybe as well as a camera facing to the house
from an external point, you might want a camera facing out to
the street so as to possibly get details of the vehicle in which
intruders drive to and from your property.
Internal Camera Considerations
Where are people invariably
going to pass while walking around your house? These are
the 'hot spots' you want to have monitored by a camera or
three main categories of places that bad guys will probably
First, the design of the
dwelling itself probably includes a main corridor or hallway in
your home. Or possibly there's a set of stairs between two
or more levels in the house. In such a case, you'll want
to get a camera facing these 'high traffic' essential
Second, the bad guys will
probably want to go to your lounge or den or computer room - the
places where comparatively high value portable electronic items
Third, the bad guys will
almost certainly go to your master bedroom to look through your
drawers for jewellery, guns, and other things of value.
So after setting up a camera
to guard/monitor your main traffic choke point(s), if you wish
to, you could add extra cameras in the rooms of your home where
the most tempting goodies can be found.
Hidden or Visible Cameras
There are two main reasons
for having a security surveillance video system. One is to
monitor the actions of people who are authorized to be in an
area, the other is to detect and record the presence of people
who are not authorized to be in an area.
The first scenario relates
to situations such as employees wishing to keep track of what
their employees are doing, parents wishing 'nannycams' to make
sure that babysitters are acting appropriately, and so on.
In this type of situation,
sometimes having visible cameras provides a deterrent/caution to
encourage compliance with policies and procedures.
But if that is not working, sometimes having hidden cameras will then identify noncompliance
However, the focus on our
article here is not so much on this first scenario.
Instead, we are focusing on the second scenario -
detecting/recording unauthorized personnel in an area.
Some people like to keep
their cameras hidden, even in this second scenario. But
the reasons for doing so are generally not as persuasive as the
reasons for making the cameras visible.
Prevention is better (and more
assured) than cure
It is important to realize
that your highest priority is not to catch a person who was
filmed in the process of previously burgling your house.
Even if you get extensive footage of highest quality imagery
clearly showing a person or persons at work burgling your house,
there's no guarantee that the police can (or will even try to) use this to
identify, locate, arrest, prosecute and convict the perpetrator,
and there's even less guarantee they'll be able to recover your
Instead, your highest
priority is to deter criminals from choosing your home as their
next burglary (or, massively more scary, home invasion) target.
That is why alarm monitoring companies give you a sign to put in
the front of your property.
The reality is that your
average burglar has thousands more properties to choose between
than he can possibly turn over when going on a day's breaking
and entering. So he will choose the 'low fruit' - the
easiest houses with the fewest complicating factors. He
will choose a house preferably not so visible from the street,
without a dog, and absolutely without any signs of a security
Why would any burglar choose
to wrestle with a security system when the houses on either side
are probably totally unprotected? So visible security
systems will definitely deter casual burglars.
Assuming you have security
cameras that are transmitting their imagery to some protected
storage location, and assuming that they can't be disabled by
someone sneaking up unseen from behind, it makes a great deal of
sense to make them visible. Make them very visible - add
signs around your property 'warning' people about your security
cameras, and maybe even paint the cameras in bright stripes or
place bright backboards behind them outside.
The most prevention value
comes from external cameras - cameras which, if seen,
may dissuade a potential burglar from proceeding to actually
break in to your house.
Once the burglar is in your
house, there is less preventative value in highly visible
cameras and a burglar is more likely then just to disable the
camera or ignore it, and possibly to then rush through the rest
of his burglarizing, getting out of the house before the police
arrive. They might well reason that they've
already committed a crime and already been filmed doing so, and
so decide to simply carry on and quickly complete their nefarious activities.
So while we recommend
deliberately making your cameras prominent outside, that is less
a factor for inside, and you should simply locate your cameras
inside wherever it makes most sense for them to be, without
concerning yourself about their visibility or concealment.
Here's an interesting way of
adding to the visual warning factor of your system.
Have you ever noticed the
height measuring strips on the insides of the door frames in
convenience stores? Why not create a similar thing, but on
the outside of any exterior doors you are monitoring externally.
Not only might this help you
to get a more accurate estimate of a bad guy's height, but it
will also add another visual deterrent to someone approaching
your door and considering any sort of bad thing.
Tell-tale recording lights
Here is one additional
consideration. Some security cameras will give a visual
indication when they are active and filming/recording.
On the face of it, having
the camera actually showing that it is actively recording might
seem to be even more of a deterrent. But this is probably not
the case. Firstly, it assumes that a bad guy would
understand what the indicator light means when it comes on or
flashes or whatever.
Secondly, there's no point
in letting the bad guys use this information to practice and
work out exactly how sensitive your detection settings are and
where the dead zones might be.
If you can adjust this
setting, we'd suggest turning it off.
Day and Night Location Issues
When you're choosing your
camera locations and angles, you want to be sure they won't have
bright lights shining into them, either during the day or night.
Cameras typically have
auto-exposure systems that will average the exposure across the
image as best they can. If the entire image has similar
light/shade values, this works perfectly. But if there is
a very strong light in one part of the image, the rest of the
image will be balanced out by making it too dark, and you'll end
up with an image that has a bright featureless light in one part
and a too dark and indistinct image in the rest of it.
Very bright lights can also
harm the sensors inside cameras.
During the day, you want to
do the best you can to make sure the sun won't directly shine
into them at any stage. And at night, you want to be sure
that there aren't any streetlights or other lights that will
shine into the camera.
Data Storage Location
Your cameras are only
helpful if you are able to subsequently access the imagery they
If a bad guy steals your
cameras and also steals the computer onto which you were saving
the video the cameras were capturing, you're left with nothing.
The good news is that it is
rather unlikely that your cameras would be stolen.
Furthermore - and
particularly if you have a Logitech Alert system, the cameras
are simultaneously storing their video onto both a Micro-SD card
in the camera and also to a central computer that you can
designate. That way, you are able to retrieve either the
video from the camera (before it is over-written by more recent
video) or from your central computer.
However, the computer on
which you store the video is a point of vulnerability.
What is one of the things thieves most like to steal?
Computers. So there's a significant risk your computer
will be stolen.
For this reason, you might
want to consider buying an inexpensive computer - possibly even
a netbook type computer, costing a mere $200 or so, and hiding
it in some obscure part of the house, using the netbook as your
hidden data storage resource for the cameras.
There are several different
forms of motion sensing systems used by home security systems.
Some systems use infra-red detection of shifting heat patterns,
some are ultra-sonic, and others use radar.
Each has pluses and minuses,
and varying degrees of sensitivity to genuine alerts and false
However, most security/video
cameras will use a built in system whereby the camera compares
the images on each successive picture it takes. If the two
images are mostly the same, it considers no motion as having
But if there is a change,
then that may be a significant motion detection and trigger
whatever event the camera system should do upon detecting motion
- typically start recording, and possibly send notifications to
pagers, text messages to cell phones, or something else.
In programming up the motion
detection system, you will usually find you have several
different settings you can adjust. You of course will wish
to walk a fine line between settings that are too sensitive and
accordingly create a lot of false alerts, and settings that are
too insensitive, allowing bad guys to sneak past, undetected.
On the other hand, if
there's no real penalty for false alarms, it is better to err on
the too sensitive side. You don't want to be calling an
alarm company or the police department for anything other than a
99.9% guaranteed real burglary, because police departments will
often start fining you for false call-outs and/or ignore your
calls in the future.
But if the only downside to
a false alarm is another text message to your cell phone, that's
probably not a problem. It could even be said to be a good
idea to have occasional false alarms, because that also sends
you an implied notification that the system is working properly.
If you don't get a false
alarm every so often, after normally receiving a couple every
day, it signals an implied warning to check and see if something
has happened to your system.
Most camera systems allow
you to define which parts of the image will be used for motion
sensing and which parts will be ignored.
This is a case where 'less
is more'. Look at the image your camera is receiving, and
decide where in that image people are likely to appear. If
part of the image is somewhere where no human motion would be
detected (too high up or too low down) then take those out of
the area where motion detection occurs. By doing this,
you're simply reducing the number of false alerts you'll get by
other types of motion seeming events in those areas.
Look also for areas where
there might be likely to be false alerts. An example would
be an outside camera that has trees and bushes in the
background. What happens when the wind blows and the
branches start swaying in the breeze? False alerts, of
course. So try and eliminate areas that will give you
The smaller the zone you end
up with for triggering motion sensing alerts, the fewer the
false alarms you will have. You might also need to fine
tune the sensitivity, however - for example if you just have a
narrow zone which will only trap motion from part of a person's
body, you might need to increase the sensitivity due to less
motion being available for the camera.
If you have cats or dogs
inside, you might want to not include the first foot or so above
the floor in your detection zone.
Most systems have some type
of sensitivity adjustment to vary the amount of motion needed to
set off an alert.
Some even provide some sort
of visual display to show when motion is being detected, so as
you scale up or down the sensitivity, you can see the effects on
a monitoring screen.
Otherwise, you should
probably start at about a mid level value, then after a day or
two you'll have a feeling for if it is too sensitive or too
You'll know if it is too
sensitive, because you'll be getting false positive alerts.
To test for it being too insensitive, simply go and act like a
burglar yourself at different times of day and night, in
different lighting conditions, and make sure that you always
trip an alert.
Here's how to best and most
quickly adjust the sensitivity. Let's assume you have a
sensitivity scale from 0 - 100 (100 meaning most sensitive).
Start off with a setting of
50 - halfway between the two extremes. After however long,
decide if it is too sensitive or too insensitive. If it is
too sensitive, move the setting to a new value halfway between
its earlier value and the minimum, ie, to 25. If it is too
insensitive, move it to a value halfway between the past value
and the maximum - ie to 75.
You'll soon get a feeling
for if the new setting has now become too sensitive or too
insensitive. Make another adjustment to move the setting
halfway between its previous value (ie 25 or 75) and either the
minimum/maximum (if you need to keep adjusting it the same way)
or halfway back to the value before that (ie 50). So your
new setting will be either 12.5, 37.5, 62.5 or 87.5.
Then after another test
period, move the value again by another half value in whichever
direction seems most appropriate, up or down (ie by 6 units).
And then, after another test period, move the value again by
another half of a half value (ie by 3 units).
Keep moving in these small 3
unit values until you've gone too far and need to reverse
direction, and then start moving in 1.5 unit values.
As you make these changes,
keep a record of each change you make so you have a history and
record of your setting and experiences at each setting.
This might sound
complicated, but it is the fastest way to get to exactly an
ideal value (analogous to a 'binary sort').
Note that each camera will
need its own calibration process and will likely end up with a
different value for sensitivity.
Note also that any time you
make any adjustment to the camera you'll need to recalibrate its
If you have a setting that
determines how long motion must be detected continually before
triggering an alert, think this through. You don't want to
set it to 1/100th of a second, because even a brief flash of
light might then be mistaken as motion.
But you don't want to go to
the other extreme and set it for eg 10 seconds, because that
would probably be such a long detection period that people could
walk into the camera's field of view, through the field of view,
and right out the other end again in less than the ten seconds
and so the motion detection would never be triggered.
A too long detection period
has two downsides - you need to consider them both.
Firstly, unless the system can be set to start recording from a
period before the trigger event, you've lost most/all of
the significant movement from your recording.
It might sound impossible to
start recording after something has already happened, but good
camera systems keep a few seconds of data in their memory, and
so can start recording not only from the point at which the
trigger event occurs, but can also add the few seconds of past
data that was in their memory too
Secondly, if it only takes
eight seconds for a person walking at normal/slow speed to go
through the camera's field of view, and you have the motion
period set for ten seconds, no-one is going to trigger the
For most people, a time
somewhere between about 0.5 seconds and 2 seconds will probably
be correct. Maybe start at about one second then adjust as
needed up or down.
Fine Tuning the Motion
When you get false alarms,
see if you can play back the video to see what caused the alert,
and then think about which of the different settings you can
adjust could be changed to stop that alert triggering again.
Some things that the camera
might interpret as motion include shifting patterns of light and
shade. Are there reflections or shadows that come and go?
Are there leaves on the ground or on the trees that are moving?
Are there pets or birds that are causing false alarms? Do
lights from passing cars shine onto your curtains or through
your windows (a sudden appearance of brightness is usually
confused by a camera as 'motion').
Another problem can be bad
weather - in particular, it is very difficult for a camera to
distinguish between snow falling and some other type of motion.
Now that you know a lot
about how and where to set your cameras, it is time to talk
about the types of cameras you should get, and the integrated
system they provide for your home protection.
Please click on to the next
part of this series for a detailed review of one of the best
home video monitoring systems currently available, the Logitech
Part 1 of a series on home security/video monitoring systems; please
How to Best Set Up Video
Monitoring at Your Home
2. Logitech Alert 750
review part 1
3. Logitech Alert 750
review part 2
4. Logitech Alert 750 review part 3
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12 Nov 2010, last update
21 Jul 2020
You may freely reproduce or distribute this article for noncommercial purposes as long as you give credit to me as original writer.