This article provides an overview of the design process in order to see how the elements fit together to form a system, and attempts to explain the role of each element in that system. We won't attempt to describe the detailed procedures for configuring the devices; that changes from one manufacturer to another, and the manufacturer's procedure is far more detailed, and far less confusing than anything we could provide here.

Lights! Camera! Action! Install your very own camera system and make it available on the 'Net!

Bill Hubbard | ThermoSight, Inc



Lights! Camera! Action!
Install your very own camera system
and make it available on the 'Net!
Bill Hubbard ThermoSight, Inc

This article provides an overview of the design process in order to see how the elements fit together to form a system, and attempts to explain the role of each element in that system. We won't attempt to describe the detailed procedures for configuring the devices; that changes from one manufacturer to another, and the manufacturer's procedure is far more detailed, and far less confusing than anything we could provide here.


Perhaps the most worrisome aspect of installing a video system in one's home is that so much of the typical system is unknown to the average homeowner.

Among the concerns most often encountered are …

  • Appearance: Homeowners are concerned how this equipment will affect the exterior lines and interior ambience of the home
  • Utility: Homeowners want to maximize the return on investment, but don't fully appreciate all that the system can provide to them.
  • Complexity - people fear that the system is too complicated.
  • Privacy: The Holy Grail of concerns - homeowners want to avoid having the cameras turned on them.

Those concerns and others are frequently addressed as follows …

Regarding appearance, the relatively small size of modern cameras, coupled with careful placement and professional installation minimizes visibility, thus retaining the exterior lines of the house. And interior cameras, those embedded in every-day household items for instance, are virtually invisible.

Regarding utility, camera systems in the home provide a number of benefits probably best summed in the two words: security and convenience. They provide, for instance, a means of watching the driveway, front yard, pet's area, garage, or swimming pool; they provide a dated, time-stamped video record of all visitors to the property; they'll send a message to you on your SMS cell phone; and they open your home to relatives and friends across town and around the world.

Regarding technical issues and complexity, virtually all engineering issues were resolved long ago. Today's systems are largely "Plug 'n Play". Actually, it's rather surprising how few technical issues remain … and even those are generally just "cut and paste" parameters from one document to another.

And finally, privacy, certainly a major concern, is probably best addressed by passwords, thoughtful use of wireless communications, treating an IP address as one would an unlisted phone number, and above all, rational decisions regarding camera placement and access.

Once these concerns are addressed and the decision to proceed is made, the actual installation is fairly simple and straightforward.

This article provides an overview of the design process in order to see how the elements fit together to form a system, and attempts to explain the role of each element in that system. We won't attempt to describe the detailed procedures for configuring the devices; that changes from one manufacturer to another, and the manufacturer's procedure is far more detailed, and far less confusing than anything we could provide here. We will, however, discuss what needs to be done, and why.

Before beginning, however, we should point out that there is no one general solution … the solution presented here was simply the best for this particular application.

This application is a four-camera system arranged as follows …

1) Camera 1 covers the driveway and front yard, providing a dated, time-stamped record of visitors. (Night vision capabilities or a small visible light extend that coverage to 24 hours per day).

2) Camera 2 covers the front door.

3) Camera 3 covers the garage. When enabled, the camera may trigger the home-alarm system if sufficient motion is detected in the user-specified location.

4) Camera 4 covers the back yard and swimming pool.

Because each camera is mounted on or in the home, all are cabled. There are no wireless links in this installation.

This homeowner had the cameras installed and wired by professionals. The cameras, even with enclosures, were small enough and placed in such a way as to avoid altering the lines of the home. The cabling is covered by a molding resembling the color of the home's exterior paint, and is routed in such a way as to blend with, and be hidden by the home's exterior lines. Indeed, thoughtful decisions regarding placement, size and color yields a system of cameras and cabling which is quite inconspicuous .

Following the installation and wiring of the cameras, three of the four video cables were brought into the garage through the same entry point the broadband cable uses. The fourth cable, originating in the garage, terminates with the other three.

A lockable cabinet was installed in the garage wall, with a small shelf placed immediately above the cabinet. The shelf holds a video server to which all four video cables are connected. The video server accepts these inputs, but also makes them available as inputs to the cabinet immediately below. It is here that the camera video is introduced into the home's television system.

This home was previously wired for cable TV, with 11 cable outlets in the home. A twelfth cable outlet, a maintenance outlet, was installed beside the cabinet.

Through this outlet, the homeowner may plug a small TV into the television system, tune to the appropriate channel, and view the video from each of the four cameras. This is not only a convenient point to monitor the system, but also simplifies setting and displaying the date and time presented by two cameras.

Interfacing cameras & TV

There are three active elements of the television interface: the modulator(s), the 'video engine', and the drivers.

The role of a modulator is to merge the camera video with a carrier frequency associated with a specific television channel. Thus, the camera video is 'shifted' to a frequency that the television's tuner can acquire. The result is that the camera video becomes just another television channel, like any other.

The role of the video engine is to merge the modulated camera video (i.e. the output of the modulator) with the television video provided by the antenna, cable TV, or satellite system, producing the composite video.

The role of the video drivers is to amplify the composite video (broadcast TV + modulated camera video), and provide it to the cables terminating at the various cable outlets throughout the home.

In this particular case, the homeowner worked backward from the television cables. To begin, the drivers were installed in the cabinet and the cables terminating at the various cable outlets throughout the home were connected to the driver outputs.

The drivers were then 'daisy-chained' together where the input to one driver (the composite video) was fed from an output of the preceding driver. In this way, the two 1x6 drivers (one input, 6 outputs, 1 'feed') drove the 12 cable outlets.

The video engine was installed, and its output was connected to the input of the first cable driver. Next, the TV cable was connected to the input of the video engine, making the Cable TV connection available at every outlet in the home. Several outlets were tested to be certain that all was in order.

Then the first camera was integrated into the television system. First, a blank channel was assigned to carry the video for camera 1. With this particular modulator, channels 70-94, and 100-125 were available, and from these two ranges, a channel not in use by the Cable provider, channel 90, was selected.

With the aid of a simple paper clip, the modulator was tuned to channel 90, while the gain adjustment was left at its default setting.

At this point, to verify modulator functionality, the modulator's output was fed into the auxiliary video input of the video engine, and the modulator's test pattern generator was enabled. A television attached to the maintenance outlet was tuned to channel 90 to observe the test pattern generated by the modulator, thus verifying that the modulator was working properly.

Once proper operation was assured, the modulator was installed in the cabinet, and the camera video was connected to the modulator via an ordinary connector. Since the camera was not equipped with a microphone, the modulator's audio jack was left empty.

The modulator's output was reattached to the video engine's auxiliary video input, completing the first camera's installation and making its video available throughout the home.

This procedure was repeated for each of the remaining cameras, and in less than an hour, all four cameras had been integrated into the home television system.

Two important points to make are that, once connected to the television system, the cameras are also

  • Available for display and recording on a PC via a TV tuner card such as Hauppauge, and … ·
  • Available to a video server and the home network and/or the Internet by using a VCR tuner to tune to the channel desired.

Integrating the cameras into the home network.

As you may recall, a video server was placed on a shelf above the television cabinet. The four camera cables were attached to the video server so that it might sample the video as necessary, but each camera cable also looped out of the video server and was made available to a modulator in the television cabinet.

The video server digitizes the video, making it available to the home network (and the Internet, on demand) via the heart of the home network, the router.

Routers are available in different sizes, or 'ports', where each port provides an access point to connect a device such as a PC, video server, or even another router, to the home network.

The router is usually connected to the outside world via a modem (or modem-router) attached to a broadband cable or DSL line. This connection enables all devices on the home network to share the Internet access.

An Ethernet cable, covered by a discreet molding, was strung from the video server in the garage, along the wall to a point on the back wall adjacent to the room where the network router was stationed. At that point, the cable went through the wall and was terminated with a jack in the adjacent room.

At this point, there was one last step before the homeowner could attach the server to the home net … it was necessary to inform the server of its network address.

Each manufacturer has a different procedure for this simple task. Suffice to say that each involves connecting a PC to the server via an Ethernet 'cross-over' cable (functionally similar to an RS-232 null-modem cable).

In this case, the homeowner connected a laptop to the newly-installed Ethernet jack via the cross-over cable and executed the program provided by the manufacturer, thus informing the server of its network address.

When that process was complete, it was a simple matter to remove the cross-over cable and install an ordinary Ethernet cable from the wall jack to the router.

And with that, the video server and the four cameras were now available to the network (and every PC on the net), and, ultimately, the Internet (the term 'ultimately' meaning very-soon-but-not-quite-yet … Internet access requires configuring the server).

Configuring the Server

As with the network address assignment process, each manufacturer has a slightly different, but generally well-documented procedure to configure the server.

With the video server now connected to the network, the homeowner was able to communicate with the server from any PC on the net. Using the PC's browser, the homeowner addressed the server directly and was delighted to see the server respond immediately. The connection was made!

Following the directions in the user's manual, the homeowner …

  • Set the password for each of the three levels of access.
  • Set the system date and time
  • Set the image quality and size
  • Set the 'connections' (i.e. router address, system mask, domain name server addresses, etc)

In time, the homeowner went on to configure a number of other items such as FTP Client/Server, Email and message definitions, motion detection thresholds, and alarms. But for now, this home video system was On The Air!

Additional Comments

Router - The heart of the home network is an ordinary, inexpensive router. Routers are available in different sizes, or 'ports', where each port provides an access point to connect a device such as a PC or video server, or even another router, to the home network.

In addition, there is the WAN (Wide Area Network) port, connecting the router and all the devices on that router's LAN (Local Area Network) network, to the Internet.

The purpose of the router is to connect the two networks, WAN and LAN, and to manage the communications traffic between these two, and between any two devices on the LAN..

To facilitate this communication, each device associated with the LAN is assigned an address. This address may be specified by the network administrator (fixed address), or by the router itself (Dynamic Host Configuration Protocol - DHCP).

The term 'fixed address' indicates that the address remains the same until changed by the administrator. DHCP indicates that the address is assigned by the host (in this case, the router) and may change as necessary.

Not all devices can operate in the DHCP mode, including the video server installed in this home. It works exclusively with a fixed address. Consequently, the administrator must assign a permanent IP network address.

The administrator does this by connecting an Ethernet crossover-cable directly between the PC and video server, selecting an address not currently in use on the network, and assigning that address to the server with the aid of a software package provided by the manufacturer.

The address assigned is typically of the form "aaa.bbb.ccc.ddd", where "aaa.bbb.ccc" are determined by the router (such as, say, 192.168.1.ddd   or   192.168.0.ddd), and the administrator chooses "ddd", remembering to choose a 1-to-3 digit number in the range of, say, 2 to 252, and not currently in use on the network. (Consult the equipment manual to find the acceptable address range for your device!).

Having made that assignment, the next step was simply to place the video server on the Ethernet by connecting the server to a 'straight-through' Ethernet cable running between the video server and the router in the room adjacent to the garage. However, additional work was required before the two were ready to work together.

If the homeowner had been satisfied with connecting the cameras to the home networking system exclusively, that would have been achieved, but this application called for Internet capability. Consequently, the router, in addition to being connected to the devices on the local network, must also be connected to a means of broadband access, either a cable or DSL connection. Either way, the broadband connection is terminated with a modem or router, and the networking router connects to that broadband modem or router.

In order for the world to come into the house via the Internet and communicate with the video server, it is necessary to inform the networking router of the LAN video server's address, and the type of accesses (browser or FTP, for instance) it will serve.

Re-stated, when an Internet or local (i.e.LAN) access is made, the router must be informed of the address of the device servicing that request, otherwise it wouldn't know where to route the request.

Thus it is necessary to instruct the router that the video server, for instance, will service all port 80 (WEB server) requests, and perhaps all port 21 (FTP) requests (if the homeowner so chooses), AND to inform the router of the server's network address. Having done that, we're Ready To Rock! (Almost).

More on configuring the Server

Virtually every server uses a different procedure to configure the device; some require scripting whereas others provide a more user-friendly, point & click process using the PC's browser, but the information required to complete the task changes little from one device to another.

This information usually includes, but is not limited to:

  • Broadband Access

  • Connections (addresses)

  • Image Parameters

  • Image Size & Quality

  • System Parameters

  • Passwords

  • Date & Time

  • Serial Bus assignments

  • Alarm Management

  • FTP Client / Server management

  • Message Definitions

  • Message/Image Scheduling

 This list may appear intimidating but the items are actually quite intuitive, and several of the items are optional … the homeowner may configure them or simply ignore them.

A cautionary comment:  NEVER ignore passwords. ALWAYS require them.

Video Server - Earlier we said that the video server digitized the video, making it available to the home network and the Internet. That's true, of course, but most video servers do much more.

Other functions performed by the server may include:

  • Password management - Maintains multiple levels of access, from user to administrator, and enforces password entry for the various activities.

  • FTP Client/Server - uploads JPEG images to specified websites, either periodically (scheduled) or 'on event' (as a result of an alarm). Also honors FTP requests for images.

  • Email Management - sends prepared-text email (with images, optionally) periodically or 'on-event'.

  • Image management - For most broadband applications, image size and quality are inversely proportional to video performance as measured in frames-per-second. Video servers generally permit the user to modify image size and quality in order to accommodate broadband capabilities.

  • Display format - Video servers handling multiple cameras generally provide a variety of options for displaying individual cameras, picture-in-picture, blocks of cameras, sequential display, etc.

  • External Interface - including providing pan, tilt, zoom commands to PTZ cameras; interfacing with alarm systems; accepting entries from 'other' external devices (motion detectors, thermometers).

  • Motion Detection - analyzing the incoming video and generating an alarm when motion breaks a specified threshold.

Wireless Links: the pros & cons - Wireless links are at the same time, both boon and bane. They make possible coverage that might not otherwise be feasible, but at the same time, provide a mechanism that may lead to the compromise of video security.

One can minimize the potential for compromise by employing only those systems that offer (generally at extra cost) directional antennas, true spread-spectrum operation, encryption, or operate at a non-standard frequency, and by avoiding any wireless system or camera operating as a WiFi device.

A very informative article on the subject, titled "Nanny-Cam may leave a home exposed" is  (currently) available at http://www.nytimes.com/2002/04/14/technology/14SPY.html.

Broadband Access - If placing one's camera video on the 'Net is a primary goal, the homeowner should be certain that broadband access is available in his or her neighborhood before ordering the camera system. Broadband availability is rather "iffy", in that it's simply unavailable in many areas around the country. And these days, broadband providers are in no hurry to extend the existing coverage.

Also, if it is available, be sure to ask about the upload rate. Broadband speed is measured with a download/upload rate, for instance 768K/128K, where the second number is the upload rate in bits per second. Where most homeowners care most about the download rate (i.e. how quickly can they download that image from the website?), homeowners with video servers are at least as concerned about the upload rate (i.e. how quickly can they pump out the video to visitors?). The upload/download rate may be measured at http://www.dslreports.com/tools.

There is very little more annoying to a visitor than video running slowly or in spurts. Image size and quality, and broadband upload rate are factors in the speed of the video as received by visitors. Generally, there is a direct relationship between image size and quality, and upload rate, and the server administrator should take this into consideration when configuring the server for image size and quality.

Sources of additional information

Covert interior cameras:

Television Integration:

 Home Network:

  • www.linksys.com                              - routers and other networking equipment
  • www.proxim.com                              - routers and other networking equipment
  • www.hauppauge.com                        - TV tuners for PCs

Video Servers:

 Security Issues:

·        http://www.nytimes.com/2002/04/14/technology/14SPY.html


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