|
1)
Computer
Back to Top
To Home Page
The computer is used to run the application software
that you want to project on the large video projection screen. This
software can be anything from the popular Microsoft PowerPoint package to
anything you can imagine. PowerPoint or Corel Presentations Plus is
specifically designed to make graphical presentations easier to set up
with numerous backgrounds and effects. But, you can use any software
including word processing to make simple presentations. If you can see it
on your computer screen you can project it.
The computer does not have to be anything fancy or
expensive. Any basic machine can do the job though faster machines will
make the work a little quicker as far as set up, but since the
presentation is slide by slide anyway, the only side effect of using slow
machines is a hesitation when you give the command to change slides.
However, given today’s very fast basic machines, I doubt you will have any
trouble with any machines on sale if you want to pinch pennies.
2)
Sending your video and data images to more than one display
For computer generated images
Back to Top
To Home Page
It is usually convenient to see a local monitor as
you set up your presentation or to monitor your presentation as you go if
you are the presenter. For example, if you are using a notebook computer
at the podium, usually the projection screen is somehow mounted out of
your immediate view. You are facing the audience and the audience is
looking at the screen. It usually is not easy to turn around and look at
the screen every time you change slides to confirm where you are in your
presentation.
Most notebook computers allow you to view the
notebooks screen at the same time you are sending a signal to the data
projector via an external rear mounted connector on the notebook PC.
Therefore, you can use the notebooks screen to view what is on the
projection screen. Desktop machines ordinarily do not have this feature.
You will have to buy another video card, buy a dual output video card, or
use a VGA signal splitter to send the video to the computer monitor and
the video data projector.
For NTSC video signals
Back to Top
To Home Page
To split signals of NTSC you need an audio / video
distribution amplifier. Remember, I am talking about line level audio and
video signals coming out of the VCR, for example, yellow, red, and white
RCA jacks on the back. I am NOT talking about where you connect the cable
or antenna connectors, the screw on F connector. The signals required for
the F connections are RF or radio frequency signals. You cannot get video
from here to send to your projector.
You cannot simply split a video signal by just
splicing the wires into two different directions. You will have serious
signal loss. You can get a simple AV DA (audio video distribution
amplifier) at Radio Shack that will split the signal into 4 directions.
These work fine for simple systems. More complex systems will require more
advanced signal loss correction features.
3) How
video data signals are wired to the projector
Back to Top
To Home Page
The typical projector has several inputs for
connecting computers and video sources. Some projectors have two or more
computer connections, a special digital connector, fiber optic link, BNC
connectors for RGB video, and S-Video inputs. There is no standard so
think about what you want to project and how many sources you intend to
use to decide if you want to buy a projector with all of the inputs built
in or whether you will need to use an outboard processor or switch to
connect the video and data sources you want to use to the projector. The
connections below are for simple installations that cover the majority of
users.
For computer
VGA signals (computer video outputs) are sent to the
projector using either a 15 pin D sub connector or individual RGB (Red,
Blue, and Green) cables with sync. The 15 pin connector is the same type
on your typical PC monitor. It’s not uncommon to use runs of 100 feet or
more with excellent results.
RGB cables are made up using “cablevision” type
wire, RG-58 or RG-6, with BNC twist and lock connectors on both ends.
Depending upon the application, this can mean running at least 3 or 5
cables from the PC to the projector. The idea here is that several larger
cables will have lower loss over longer runs of cable. If the projector is
several hundred feet away RGB may be the way to go.
For video images from VCR’s, DVD’s, and other NTSC
video sources
Back to Top
To Home Page
If you want to send video output from a VCR, DVD,
computer generated NTSC video outputs most likely the connectors you will
use will be the RCA phono video output connector coded with a yellow ring
or core, or an S-Video connector. Most video sources have at least these
connections and some will have more advanced features. But, for the
typical installation either the RCA phono jack or the S-video will be
used.
For those that want a more detailed knowledge of the
difference between the RCA jack and the S-video jack, the RCA jack sends a
composite video signal with the black and white picture and the color
information superimposed on one signal. In the US this is called the NTSC
standard for American broadcast standards. European countries use the PAL
system.
The S-Video jack sends two signals, the black and
white signal is sent on two wires, and the color information is sent on
two other wires. All things being equal the S-Video jack should provide
better image quality for video images. However, given the distance the
projected image will be viewed from, the added expense of using the
S-Video output may or may not make any appreciable difference to the
viewing audience.
4) Remote
controlling the screen and projector
Back to Top
To Home Page
You need to be able to control the projector and
screen from where you are operating the computer and / or video equipment.
If you are presenting from the podium, you want to control the projector
and screen from there along with your notebook PC. If you are the
technician in a control room or booth of course you want the controls
there. A lot of installations requires multiple control stations from
anywhere in the room.
There are two general avenues of thought of remote
control: wired or wireless
A wired remote control will have in wall or desk top
controls hard wired to the screen and video projector. These controls will
allow the screen to be raised or lowered and control all features of the
video projector. Hard wired is best used where there may be interference
problems with other wireless equipment or when keeping up with handheld
remote controls is too much hassle.
All of the same features as above are easily obtained
with wireless remote control units. You can get radio controlled devices
or infra red systems. The choice depends upon which will work best for the
application. An infra red system does not transmit beyond the walls of the
room. A radio controlled system can and my cause interference problems in
other areas of the building.
The choice of wired or wireless falls within the use
of the facility more than anything else. A convention room that will be
rented will lean toward a hard wired system because of headaches with
having to chase down the remote control units after a rental. If one
person or group is using the system or you want maximum flexibility and
convenience of operation then the wireless system is the best choice.
Projectors come with an infra red remote control unit. Screens do not and
remote controls are ordered separately.
You will
most likely need a remote control repeater or range extender for any
handheld remote control system. Most handheld remotes are limited in range
to about 30 feet or so. If your screen and projector are beyond this range
the remote control simply won’t work. It’s like taking your TV remote and
walking into another room or out of range of the TV. It can’t “shoot” that
far. Range extenders are devices that sit on a desk top or mount in the
ceiling near the location of where you want to control the system, and
retransmit or boost the signal so the projector and screen remote
receivers can “hear or see” your remote signals.
Back to Top
To Home Page |
