How to use the video projection equipment in OldH 204

This is a guide to the use of the video projection equipment in OldH 204. Since it has hardly been used (yet), some of this information is provisional.

What is the projection equipment?

Mounted on the ceiling is an NEC video-driven projector. It projects onto a large screen on the wall to the students' left, as they sit in class. The projection is very bright (1100 lumens) and because the room is small, the image is both large and brilliant. Normally half the room lights would be left on during use. (The lights adjacent to the the screen wall would be off.) Below the front blackboard is a small box with several connectors for video. Although this page will only discuss the use of computer input, other sources (such as a VCR) can also be used.

In brief, how is it used?

The instructor brings a laptop (preferably already on) to the classroom. The projector is turned on and the laptop is connected to the front box. Details of this process will be described later, but the entire process can be accomplished easily in under one minute. You can then use materials stored on the laptop to supplement your lecture, by alternately writing on the blackboard and referring to the image on the screen.

If it's so easy, why should I read any more?

First and foremost because there are truly horrible traps you can fall into. Secondly, there are a number of ways in which your presentation can be improved. Thirdly, I have a few thoughts about content.

Presentation content

In short, one or two well-chosen graphics can make the difference between a lackluster and outstanding lecture. In more detail, here are what I see as the "rules" for these type of video presentations:

Keep it graphical. Ideally, every presentation should have at least some graphical content.

Don't try to do too much. Do not plan on displaying the equivalent of twenty transparencies. Instead, plan to move very slowly from image to image, keeping each on the screen for several minutes.

Use the blackboard extensively. Both the blackboard and screen are clearly visible at the same time. Use this to your advantage.

Enable after-class access. Put electronic materials in a publicly accessible place so the students can examine them at their leisure.

The details

Here is everything I know, or think I know. If you spot any errors or omissions, please tell me!

What to bring to class

You will need a laptop computer (preferably with a full battery charge), and a 9' video cable. That's all. There is a remote control unit that goes with the projector, which is handy, but it is not really needed. You can borrow the remote and the manual if you wish. If you want to use the network during your presentation, bring a network connection cable. I haven't tried this and do not really recommend it anyway, unless it is essential for what you are doing.

Starting up (and closing down)

I'll assume that your laptop is already booted. This will make things easier. Place the laptop on the front table. If you don't want to worry about tripping, move the table up against the front wall. Otherwise, watch your step!

Pull down the shades. Pull down the screen. Turn off half the lights. Connect the video cable from the back of your laptop to the blue connector on the wall. Stand on a chair and push the on/off button on the bottom of the projection unit. Initiate video output from your laptop. (See below.) You're ready to go!

When you are all down, proceed as follows. Terminate video output from your laptop. Press the on/off button on the bottom of the projection unit, holding it for about a second. (The lamp should go off.) Disconnect the video cable. Raise the screen. Done!

Are all laptops interchangeable?

Definitely not. There is quite a bit of information that is potentially machine-specific. The optimal situation is that you have your own machine, and learn the operational details (to be described) for it. If you are borrowing a machine (on several occasions), be sure that it is the same machine. Furthermore, there is no substitute for testing out the particular machine in the room itself.

Getting video output

The single most important thing you need to know is how to get your laptop to emit a video signal. The answer is very complicated. In fact, it is so complicated that you will probably want to ask the system administrator about it. Nevertheless, I present the details (as best I know them) here.

1. Most (or all) laptops have a "key sequence" to toggle video output. In principal it goes like this. You hold down a key labelled Fn and push F3. Hereafter I will say simply that you push Fn-F3. In fact, F3 may be some other key. On my machine F3 is labelled "LCD/CRT" in blue, so I know it is the right key.

2. It is possible that pushing Fn-F3 will cause the machine to hang, forcing a hard reboot (which will take several minutes). Read on to avoid this calamity!

3. The theory is that pushing Fn-F3 the first time blanks the laptop screen and causes a video signal to come out the back of the computer; pushing it the second time causes both laptop and external video output; pushing it a third time returns you to the original state. Each operation can take several seconds to complete, so you should be a bit patient. Never push twice in rapid succession.

4. Under Windows NT, this works (at least on my machine). So if you plan to use NT, that is probably all you need to know about getting video output!

5. Under Linux, Fn-F3 may or may not work. Try it out, but not in front of your class! Assuming that it does not, there is a very technical workaround, that works at least on my machine. It is done by editing /etc/X11/XF86Config, as follows. Under Section "Device" add the lines Option "intern_disp" and Option "extern_disp". This will take effect as soon as you restart X. On my machine, you don't get external video until you restart X. In practice this means that you bring the laptop to class with the graphical login screen up, you choose the option to restart X (under shutdown), and then you log in.

Power management

Unless your laptop is a complete piece of junk, its battery (if fully charged) should power a full hour's activities. Therefore you will not need any power management. In fact, many of the desirable features of power management (such as blanking your screen and going into suspend mode) are extremely undesirable in a classroom setting. So be sure to turn off power management, screen blankers, auto-screen-lockers, and the like. Right now I don't know the full answer regarding how to do this. For example, on my machine, under Linux/Gnome, the screen blanks after ten minutes of inactivity, no matter what I do. (This doesn't happen under Linux/KDE.)

Display quality

There are two issues here. First, how to make sure that at any given instant your image is as good as possible, and second, how to make sure that the elapsed time (in getting images up) is as short as possible.

1. Ultimately, you are limited by the display resolution of your laptop. Less expensive models (e.g. mine) are 800x600; more expensive ones are 1024x768; the projector itself supports even higher resolution. Theoretically, a laptop could have an external video signal at higher resolution than its own video signal, but I don't think any of our models support this.

2. As a rule, make your fonts large. I prefer eighteen point, but smaller size fonts are quite visible from throughout the room. You may also discover that (even within a fixed size) some font looks better than others. Experiment!

3. Antialiased fonts look better, but are not always available. For example, web browsers do not use them for text. But a web browser could use them as part of an embedded image. A tex document can probably be viewed using antialiased fonts.

4. Use color!

5. Unclutter your screen.

Using a browser

To reduce time delays and dependence on the network, it is better if the web pages you need are stored on your laptop. This can be done under either Linux or Windows. Under Windows you can use either Netscape or Internet Explorer.

Experiment with the available fonts. One may look much better than the others. Set your preferences accordingly.

To achieve an uncluttered look, it is best to remove toolbars and such. It is possible to completely eliminate everything except the page content. This gives a really clean look. Here is how I do it under Linux/Gnome/Netscape. I have not been able to achieve the same effect under Linux/KDE/Netscape.

0. Tell Gnome to auto-hide the toolbar at the bottom, with minimal residual presence on the screen.

1. Create a gateway page to the page you want to present. For a model, look at http://bigbox.unl.edu/plane/open_laptop.htm. It is designed to open a window slightly larger than the actual screen size. That way, you don't see the scrollbar, and can use the keys to move around instead.

2. Open Netscape, and tell it to go the gateway page. Tell the window manager (via alt-right-click) to make the window borderless, to maximize its size, and to remember attributes. You may have to edit .gnome/session to make sure that Gnome will remember which page to go to. Logout, saving your current setup as you do.

3. When you log back in (say in class), click on the box in the gateway page. Done! If you've done this right, you'll see absolutely nothing except the page content.

4. You can use alt-> and alt<- to move forward and back between pages; alt-tab brings another window to the foreground.

Using `Mathematica`

Using Mathematica, you can produce absolutely stunning graphics. For Plot commands, when you want to produce a final copy (for presentation), use the option PlotPoints -> n, for some large n, to produce a finely rendered copy.

If you play around with Mathematica prior to a lecture, and then plan to continue in class (without rebooting the machine), it is a good idea to kill the kernel and then restart it. Otherwise, Mathematica may cause you grief by remembering values for variables that you entered prior to class.