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MCU servers are usually hosted by an MCU service provider. Companies that frequently
hold multipoint videoconferencing sessions can set up their own MCU in-house, often at
great cost. A good alternative is emerging from the open source community (surprise!)
known as the “OpenH323 Project.” More on this and free software is at
www.openh323.org.

Multipoint Control Unit servers act as call handlers. Software that is meant to only handle a
single videoconferencing session can interact with many participants through an MCU.



Understanding Internet Video Chatting
As mentioned previously, many newer products are entering the scene as video “chatting”
clients. The most popular of these are Microsoft Messenger and AOL Instant Messenger.
Some others include Apple iChat, iVisit, iSpQ, CUWorld (descendant of CU-SeeMe),
CamFrog, ICUII, and TrackerCam.

For another list of video products, visit: http://myhome.hanafos.com/˜soonjp/.




The problem with Internet video chatting is the reliance on a single, central, authentication
system. Users must register with the service provider first, then sign-on to the service over the
Internet. After that a managed list of “buddies” or “rooms” is made available.
This works fine when you™re “tethered” to the Internet, but it will not do for a highly mobile
peer-to-peer video session. This project requires a completely stand-alone system, without
reliance on a central server. NetMeeting fits the bill perfectly.




Step 2: Configuring NetMeeting
Since 1996, Microsoft has been working on videoconferencing in the form of its NetMeeting
program (see Figure 14-8). Until recently, this has been downloadable from the Microsoft Web
site. In 2002 Microsoft decided to change direction away from this stand-alone application to
its centralized MSN Messenger video system.
However, Microsoft continues to include NetMeeting in its current operating systems.
Windows 2000 and Windows XP have NetMeeting installed as part of the system. Earlier ver-
sions of Windows (Win 95, 98, ME, and NT) will need to download and install NetMeeting if
it™s not already installed. Since Microsoft has removed the download from their Web site, find-
ing the NetMeeting setup program will require an Internet search.
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FIGURE 14-8: The NetMeeting program.
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Finding NetMeeting on Your System
NetMeeting, although installed on Windows 2000 and XP, does not have a shortcut anywhere
on the Start Menu. There is a simple fix for this:
1. Click on the Start button and open the Run dialog.
2. In the Open text box, type conf.exe.

If this is the first time NetMeeting has been run on this computer, it will launch the Setup
Wizard. See the next section, “Configuring NetMeeting,” for details on filling in the Wizard.

If you are using an early Windows version and installed NetMeeting from the downloaded ver-
sion (nm301.exe) there will be a shortcut in the Start ➪ Programs menu.




Setting Up NetMeeting
When starting NetMeeting for the first time on a system, the startup wizard will automatically
launch. The following will step through the screens of the startup wizard:

1. NetMeeting introduction screen: Click Next
2. User Information: Fill in your name and e-mail
3. Directory server information: Disable “Log on to directory” and enable “Do not list”
4. Speed of connection: Select “Local Area Network”
5. Desktop shortcuts: Ensure both are selected to add shortcuts
6. Audio setup: Click Next
7. Speaker test: Click Test to check speaker volume
8. Microphone test: Speak into the computer microphone and adjust level
9. That™s all: Click Finish

Windows Audio Setup
A common problem discovered during the wizard is the microphone setup. If there are
problems, just click Next and read on. If the microphone worked, skip ahead to the next
section.
To adjust microphone settings, perform these steps:

1. Go to Start ➪ Control Panel ➪ Sounds.
2. Under “Device volume,” click the Advanced button.
3. The Master Volume Control window should open.
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FIGURE 14-9: Recording Controls window with Microphone selected.

4. On the Options menu, click Properties.
5. On the Properties panel, under “Adjust Volume for,” click Recording.
6. Under “Show the following volume controls,” ensure that Microphone is enabled.
7. Click OK on the properties panel. The window displayed should now look something
like Figure 14-9, the Recording Control window with several slider bars, including the
Microphone control.
8. Ensure that Microphone shows a checkmark in the Select box (see Figure 14-9).
9. Ensure that the slider bar is at or near the top of the Volume control (see Figure 14-9).
10. Close the Recording Control window.

The microphone recording level should now be set and ready to use in NetMeeting. To make fine
tuning adjustments within NetMeeting, use the Audio Tuning Wizard under the Tools menu.
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FIGURE 14-10: Host a Meeting settings window.

NetMeeting Video Setup
NetMeeting will automatically detect if a camera is installed and select it. If there is more than
one camera, NetMeeting will prompt you for which to use as the video source.
When NetMeeting is running, it does not show your video by default. To enable video, go to the
Tools ➪ Video menu and select Send. If video is not displayed at this point, further troubleshoot-
ing is required. Make sure the camera is attached and is powered on. If the camera is still not
detected, further troubleshooting is required. Contact the camera manufacturer for support.
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If the Video menu item is disabled in NetMeeting, that means a compatible camera was not
detected. Follow the same troubleshooting procedures as if there were no video. Additionally,
check with the manufacturer if there is support for Video for Windows.



Making a NetMeeting Call
To connect to other computers with NetMeeting, one computer acts as a host, and the other
“calls” the host. Determine which computer will act as a host and select the Call, or Host
Meeting menu item. A new options window will open like that shown in Figure 14-10.
Assign any values that are relevant and click OK.
To make a call to the host, all you need is the host computer™s TCP/IP address. To get the IP
address in NetMeeting, have the host open the Help ➪ About dialog. It lists all the IP
addresses on the system.
To place a call, open the Call menu and select New Call. In the “To:” field, enter the IP
address of the host computer and click OK. That™s it.


Step 3: Setting Up a Wi-Fi Link
The concept is to have two cars communicate while being fairly close to each other, but not
too close. Figure 14-11 shows two cars in a videoconference session.
To create a link between the two cars, set up a peer-to-peer (ad-hoc) wireless network between
the two laptops. Alternatively, use a wireless access point in one car, and have both computers
connect to the AP.

If you decide to use a wireless access point as the central network device, ensure that the AP
allows wireless clients to connect to each other over the wireless link. Certain APs may inhibit
wireless clients from connecting to each other for enhanced client security.



First, set up the two laptops within range of each other, perhaps a few feet, and establish a
peer-to-peer connection between the computers. The precise method for doing this will vary
greatly for each computer and wireless card, but make sure these settings match:

SSID”same on both
Channel”same on both (if available)
WEP key”same on both
Network Mode”ad-hoc (not infrastructure)

Figure 14-12 shows the Wireless Network Configuration screen on Windows XP. This exam-
ple shows the configuration for an ad-hoc network. Notice the option is enabled for “This is a
computer-to-computer (ad hoc) network.”
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FIGURE 14-11: Car-to-car videoconference in progress.
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FIGURE 14-12: Windows XP Wireless Network Configuration set to ad-hoc.




FIGURE 14-13: Two computers in a videoconference test.
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When your ad-hoc network is active, start a NetMeeting conference as a test. Figure 14-13
shows this ridiculous yet necessary test.
Now that the computers are able to engage in a conference, it™s time to mount them in the
cars.



Step 4: Preparing the Cars
In getting ready for a car-to-car link, some important options must be considered.

How long is the trip?
What type of terrain are you traveling?
Will there be a leader and follower? Or will you be trading off?

Trip length will determine if battery power or laptop-charging AC power is needed.
It™s best to have a plan before launch. For example, if using one car as the lead, directional
antennas may be possible. If the cars will trade off, then an omni antenna is necessary.




FIGURE 14-14: Antenna options: mid-gain directional, high-gain omni, and
mid-gain omni.
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Chapter 14 ” Deploy a Car-to-Car Wireless Video Link


Selecting the Antenna
By the time you read this chapter, antenna selection should be straightforward. A highly
directional antenna would make continuous connection difficult but possible in serious,
cross-country straightaways. Figure 14-14 shows some antennas that could be used. An omni
would probably be the best overall in any situation. Opt for a high-gain omni, like 11 dBi, for
very flat roads. Use a lower-gain omni, like 5 dBi, for variable elevations.
Also, remember line-of-sight. Mountain roads are probably going to kill the signal no matter
what antenna or power is being used.
Be careful where and how the antenna is mounted. Do not have someone try to hold the
antenna inside the car. Too many variables can cause brief video-session-stopping outages. It™s
best to mount the antenna on the roof of the car. A magnet mount antenna is ideal. Otherwise,
clamping the antenna to a roof-rack is possible. If you™re using an antenna not made for vehicle
mounting (like, perhaps, a panel antenna as in Figure 14-15) take into account the high wind
velocity at vehicle speed.




FIGURE 14-15: Directional panel antennas mounted on the cars.
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Powering Your Rig
If everything will run on battery, skip to Equipment Management. Check the AC adapter on
your laptop and video camera (unless using a USB-powered camera). Multiply the voltage
times the amperage to determine the necessary wattage for the DC-to-AC inverter.

Laptop: 20 V 3.5 A 70 W
Camcorder: 8.4 V 1.5 A 12.6 W
Total: 70 W 12.6 W 82.6 W

An inverter of higher than 83 W would be sufficient to power this system. It™s a good idea to
use an inverter of at least double the wattage requirement. In this case, an inverter rated at
175 W (priced at around $40) would be ideal.

Equipment Management
Cables should be run well out of the way of driver controls, including foot pedals and the trans-
mission shifter. When placing cables, consider the possibility that something might fall during
a sudden stop or evasive turn. The laptop and camera should also be safely out of the way.

Placing the Camera
Determine the view that you want to send to the other car. Will it be the camera facing for-
ward? Or do you want everyone to see the boisterous crew in the passenger cabin? Find a posi-
tion for the camera and mount it using a suitable mounting system.
Adhesive Velcro strips work great with small USB cameras, as shown in Figure 14-16. For
bulkier cameras, a tripod strapped down to the seat may be required, as shown in Figure 14-17.
To go in style, check out the offerings by Jotto Desk (www.jottodesk.com). The company
offers top-notch laptop mounting systems.

When on a road trip with two cars, switch lead positions repeatedly when passing slower traffic.
Pulling into the left-lane, the back car pulls out first, acting as a shield for the front car to stay in
front. When moving back to the right-lane, the front car moves over first and the back car passes
to become the new front car. This method of trade-off will prevent others from getting between
your cars, keeping distance down and wireless signal strength high.

Now plan the trip by saying something like, “Let™s go to Vegas!” Mount up the cars and go!



Extra Credit: Multipoint Car Conference
This would be a challenge, but it™s conceivable that a videoconferencing MCU running on a
laptop could be installed in one of the cars. That server car would sport a wireless access point.
A number of other cars could connect to the AP and call the MCU to establish a video session.
This sort of arrangement could support at least a dozen videoconference participants, assuming
they could all stay in range of the wireless AP. Figure 14-18 shows a diagram of this scenario.
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FIGURE 14-17: Camcorder tripod strapped to the passenger seat.




FIGURE 14-16: USB camera stuck to the dashboard.
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MCU
Client Access Point Client




Client Client


FIGURE 14-18: Multiple cars videoconferencing each other.




Summary
Video is one of the most natural forms of human communications. This chapter introduced
videoconferencing and added the new concept of highly mobile wireless videoconferencing.
With a couple of laptops, video software, and a wireless connection, we overcame the isolation
of driving in a caravan. This may open up a new era in vehicular transportation. Or it may not.
At any rate, it™s fun!
Now read on to enter another realm of visual communication. Break out your digital camera
and give your pictures a new release. Create a wireless digital picture frame that™s suitable for
display in any home.
chapter
Making a Dynamic
Wireless Digital
Picture Frame
Y
ou probably have a digital camera or will get one soon. More people
are buying digital cameras now than film cameras. Because it™s
in this chapter
essentially free to take a digital picture, more pictures are being
taken than ever before.
Selecting the right
But there™s a problem. You have a hard disk full of pictures”what do you computer
do with all of them? Printing is okay for the special ones. For the rest,
though, watching a slideshow sitting at the computer just isn™t convenient.
Preparing the
computer to display
Hence, the digital picture frame. There are several on the market and many
more will follow, but only recently have they become wireless. Often it™s pictures
only the high-price models that sport a Wi-Fi interface.
Modifying the
This chapter will introduce the digital picture frame and show you how to
computer case
make one for the cost of an old laptop computer and a few extra parts.
Figure 15-1 shows a digital picture frame that is updated over Wi-Fi. With
Building the picture
a simple screen saver program, the digital picture frame, or digiframe, can
frame
cycle every 3 seconds or display a single photo for as long as you want.
Changing pictures is as simple as drag-and-drop from your desktop com-
puter to a network drive. The software automatically rescans the folder and
updates the slideshow without any manual intervention. You have to love
low-maintenance artistic expression.
Here™s what you will need for this chapter™s project:
¤ An old laptop computer with a PCMCIA slot (about $300 on eBay)
¤ PCMCIA Wi-Fi adapter
¤ Picture frame
¤ Picture frame matting
¤ Screwdrivers to take apart the laptop
¤ Wire cutters (some laptops may not need this)
¤ Soldering iron (again, some laptops may not need this)
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FIGURE 15-1: Suitable for hanging.


¤ Electrical insulation tape
¤ Adhesive Velcro strips
¤ Coping Saw



What is a Digital Picture Frame?
A digiframe merely stores pictures to display on a video screen. To make this happen, a few
things must take place:

1. An image file is created, downloaded, scanned, or digitally photographed.
2. The file is moved to the digiframe.
3. The file is stored on the frame.
4. The frame displays the file on an LCD screen.

The frame needs to have enough storage to hold some number of pictures. The amount of stor-
age on retail digital frame products in the sub-$500 price range varies from 10 pictures to
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FIGURE 15-2: Digital picture frames for sale.

1,500. The frame you™ll build here will hold thousands and costs about $300 for the computer
and Wi-Fi card, and $50 for the frame and matting. Quite a bargain for an afternoon™s work!
The problem with most digital frames on the market is they lack a convenient way to transfer
pictures from the camera to the frame. The cheapest uses a dial-up network connection and a

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