Teaching and training with computers raises the need for a big screen display. As the article attached shows there are a variety of approaches. Right click Big screen.pdf to download a spread from " Data logging in Practice". 

Projectors (specs and models have changed):

One thing we never predicted was the uptake of PowerPoint. I was in one school when they announced that the INSET session was about the begin as: ‘The PowerPoint will start in the hall in 5 minutes’. I thought: never mind the topic!

Used in lessons, video in the hall and school open days, projectors are a sought after item. Bought like motor cars: the next best is over budget so you settle on something with four wheels and seats. Projectors cost about twice the price of a computer and they are worth it.
With projectors you weigh up brightness, resolution and whether you will install or move them. Special features and higher specs solve most location problems and just a few examples make this clear. The Epson EMP 52 offers the SVGA screen resolution (800 x 600) you often find. It copes well with higher ratings, but if you switch your laptop to SVGA the image will be clearer still.
The Epson is portable, beams 1200 lumens and copes with ambient lighting. For the classroom it may be the ideal and just needs to be seen beside the Toshiba TLP 260 at 1500 lumens. The Toshiba TLP 261 is the same unit with a camera to demonstrate things. It is so ‘right’ for science, they will never want to share it. This one also has a ‘short-throw’ lens so the projector can be close to the screen.
Guarantees vary by brand – some makers do a ‘hot-swap’ if the projector goes sick. Toshiba say that a ‘dud’ lamp will fail early in its life, so you’ll find the lamp guaranteed for just three months and the machine for longer. The higher XGA resolution (1024 x 768) adds to the detail, the cost and convenience. The Toshiba TLP-T500 not only has this, in an IT room you can link to it wirelessly over the network. Pupils could, for example, show their work from their network stations. Also here is an often overlooked PC card slot, which if you travel ‘selling’ the school, lets you do a slide show without a laptop.
Also to see is the innovative NEC range where using ‘3D reform’, slanted, distorted images can be clicked square again on some models. NEC’s ‘Off Centre Positioning’ even lets you put the projector to the side of the screen. Sharp, Philips, InFocus and Sanyo also have significant ranges. I'd want to think twice about the rest and the cheapies. Don't be too swayed by having a remote control as it is more for fixed (ceiling) installations. (Using a thumb pad as a mouse to control anything more than PowerPoint requires incredible skill) 
Bear in mind that projectors are shared and set up in a hurry, so one button setup is the limit. My impulsive tip is to discard the remote control, my other is to reduce the manual to a side of A4, so people know about say, not moving it whilst hot. Do test drive your short list and match the projector to the job. Home cinema projectors, for example, are another species.
Check projector prices at projectors.co.uk and dabs.co.uk (but don't buy at dabs - the service when things go wrong is infuriating). We'd be happy to buy again from www.premier-presentation.co.uk based in Newport, Wales. Also from www.projectorpoint.co.uk in outer London.

PC on TV

The most affordable approach is to plug your computer into a television. Essentially you upgrade your desktop computer graphic card to one that has a ‘TV out’ socket. This socket may output S-video. You may get an adaptor to change this to a component video socket (yellow socket). The TV-out feature is not the same as a TV card which adds a TV tuner to your system. 

Laptops

Modern laptops may have a ‘TV out’ socket you can connect to a TV/video player. It looks like a yellow phono socket or it may be abn S-video socket. The yellow socket is called a ‘composite video’ port. You should find at least one laptop with a TV out in the ranges of Dell, Gateway, Toshiba, Ultra and Elonex.

You'll more often find S-video outputs which offer slightly better quality. The downside is that they only work with modern TVs and this limits their versatility. There are S-video to Scart leads. I have a S video to Composite adapter that came with an ATI video card. Whether it works for every S video output we don't know - eg the S-video may be NTSC and in the UK you need PAL. Try Maplin or www.keene.co.uk for the wires. I've heard several reports of people only getting monochrome images in this way - maybe the PC is setup to output US-style NTSC signals and maybe I was lucky

To output to the TV is a bit tricky - I'd suggest that you write down what you do to make it work. You might do this: Control panel > Display settings > advanced > output to TV > PAL. You may lose the normal screen display while viewing it through the TV. 

You connect the TV-out to the S-video; SCART or AV socket of a television and switch the TV to the ‘AV’ channel. The later is the hardest part if you've lost the remote control. If you need cables try www.keene.co.uk 

Some laptops have a ‘TV out' socket, this pic gives a measure of the 'not bad' screen quality.

External units

• AverMedia Technologies (UK) Ltd manufacture Multimedia and Presentation products. The most popular products for teachers and students are Key300 and AverVision100. See  www.averm.co.uk 

• Keene sell a USB to TV adapter www.keene.co.uk which looks like a very tidy solution. Here's a page from their catalogue

Click to enlarge

• Vine Micros make the CORIO range of scan convertors. Contact them at Continental Approach, Westwood Industrial Estate, MARGATE , Kent, CT9 4JG UK www.vinemicros.com

Desktops - internal units

You can fit a new card into your existing PC, usually replacing the existing graphics card. You need to find out whether your machine has an AT, PCI or AGP style video socket because this will effect what you get. Older machines with AT and PCI video sockets will need zealous research to find the right item. If you fit a second graphics card to a PC with Windows 98, 2000 or XP you gain a twin screen system. Thin-head graphics cards cost very little and seem to be easier to set up. (Having used a twin screen set-up for ages now, we're convinced this is the way to work).

• ATI All-in-Wonder – good choice for home

Computers with a TV out

The composite video feature may be present on the machine. A Yellow phono socket is thing to look for - however the display driver will need to support the output. See note above above S-video.

External TV out boxes

You can buy an add-on box such as this. These are convenient if you do not move them around - this laptop set up and all its power supplies was a fuss to get started. The USB unit from Keene (above) looks simple and effective.