If you have every been to an Imax movie, or sat close to the front of a theatre during car chase scenes, you've felt the awesome sensory illusion large visuals can provide. Now you are building your 'pit and want to replicate that feeling. Motion platforms are great, but to do them right will cost a mint. The best way to immerse yourself is to completely fill your field of vision. So off you go to buy the biggest monitor money can buy - 17", 19", 21", bigger? They still only display what is directly in front of you. You want a LARGE image. You could sacrifice image quality and buy a large screen TV, or maybe an LCD projector. The projector is the best way to go, until you see the price tag… even on eBay, LCD projectors run $2,000US and up (and the $2000 ones are not that great…).

An alternative that has worked for me and others is an LCD Panel and OHP. Before LCD Projectors, people (actually schools and businesses) could purchase LCD Panels which look like a large book that sits on an OHP and acts like a monitor. Initially they were monochrome, but quickly became colour and resolutions and technology improved until the mid - late 1990's when the self contained projectors came on the scene. My LCD panel is an ASK400 (800x600 resolution, 16 bit colour, TFT technology for fast refreshes - no LCD lag when moving fast) which I purchased on eBay for $100USD (MSRP in 1996 was $7000USD). Add a $200 OHP and you have a very satisfying projector for less then $500 that will challenge any $2000 projector on the market.

What's the catch? The catch is:

1. you are buying a used piece of equipment with no warranty or support - if it dies you may as well bury it.
2. you have a bulky OHP to set up and lots of stray light to deal with.
3. resolution is usually only 640 x 480 or 800 x 600. 1024 x 768 panels are rare as complete projectors where rapidly taking over the market by the time 1024 x 768 started becoming vogue.
4. general quality. You are using older technology that is, well old, and less efficient. Your $500 Panel / OHP setup will never be as good as a $5000 LCD projector. However, I'm sure it can easily be as good if not better then a $2000 LCD projector.

What are the benefits? As I see it the benefits are:

1. cost. This is the cheapest way to set up a large screen system. Period.
2. it's yours, so you can customize it the way you want without worry about voiding a warranty. Open it up to let it cool better. Glue, bolt, strap it to the OHP so you can mount the OHP upside down from the ceiling to get it out your hair. Most 'pits are large under takings so take some time and make the panel / OHP combination work for you.

When looking for a panel, you'll be buying used - so buyer be ware. Do some homework before bidding. These are obsolete and people are trying to get rid of them, but they are trying to get the most money possible and will sometimes leave out subtle details that will haunt you later. (I do not mean to condemn those who honestly don't know the details.)

1. Does it work? These are old technology, but in the right setup they work just fine - why get rid of it just because it's not the latest gizmo? Make sure the unit works - or else bid low.
2. Is it colour? A lot of earlier panels where monochrome. When selling a monochrome panel, sellers often just mention the brand and model. Do some research and make sure it's colour. If it isn't bid lower. Monochrome may be OK for your project, but also be aware that monochrome means older, which also means lower resolution and slower refresh rates - you will not be watching TV/ Movies or playing fast paced games for long on one of these.
3. Resolution? Try and find ones that support 800x600 natively. A lot of panels (and projectors as well) will support higher resolutions by compressing the image or by only showing a small subset and forcing you to scroll left/right/up/down. 640x480 may be adequate for side views, but really try to get one that can handle 800x600.
4. TFT / Active Matrix? As with laptop computers and projectors, TFT or Active Matrix displays are much better. They are able to refresh much quicker and are definitely worth the extra dollars.
5. Connectors - RCA, S-Video, (S)VGA? - Be very careful about the connectors. Most panels should have a PC connector (at least VGA if not SVGA), however I have seen projectors that only have S-Video / composite input - these are designed for use as a TV with a VCR or some other low quality video source. Make sure the cables are there. My ASK400 can apparently be connected to a VCR, however, the adapter was not included (I'm not too concerned, but was slightly disappointed when I realized I couldn't use it for a large screen Star Wars movie night).

When purchasing an OHP, there are some things to be aware of. I would not recommend buying a used OHP from eBay or through the mail as the shipping costs and risk of damaging the bulb will kill any cost savings. If you can find a used office / surplus dealer nearby check there. Otherwise buy a new one. Given what you're setting up - they are not that expensive.

1. LUMENS - Lumens is essentially a measure of the amount of light a 'thing' produces. (This is dumbed down - don't flame me.) Unfortunately, LCD Projectors and OHP have their Lumens measured differently. An LCD Projector with a Lumen rating of 400 will be fine in your bedroom with the lights off. An OHP projector that is recommended for LCD Panels start at 4000 Lumens. My projector is rated at 2500 lumens and with the lights off I have no complaints.
2. Lenses - OHP come in essentially 3 qualities - economical, average, overkill. A key distinguishing characteristic between these classes is the complexity of the focusing head. The first thing people will notice is that some are open (you can touch the mirror and there appears to be only on lense on the bottom) and closed (the mirror is inside a box and there appears to be a second lense on the front of the box). I have noticed that lower end projectors tend to be closed, although I'm not sure why as the extra glass and plastic would add to the cost. The upper lense is not a lense, rather it is just a dust protector. The lense is on the bottom of the head and this is where the quality comes in.
1. Economical - These have a 'single' lense. They are most noted by a the inability to get a consistent focus from the edge to the centre of the screen. Avoid these.
2. Average - These have a 'double' lense. The additional lense greatly improves the consistency of focus and is well worth the extra money.
3. Overkill - If two is better then one, then three must be better then two! Maybe, but it's not worth the extra money. Remember, the whole reason for going the LCD Panel / OHP route is to be cheaper then an LCD Projector.
3. Diode / Transformer - The primary factor in determining the Lumens of an OHP is the wattage of the bulb. Look at two models with different Lumens and chances are the form factor of the bulb will be the same - just a different wattage. So why not buy a more economical OHP and 'overclock' the bulb? One reason is the supporting electronics. The bulbs are not 120V bulbs. They are 80V. Somehow you need to reduce the 120V coming in to 80V going to the bulb. The economy OHPs use a Diode and resistor series to accomplish this. This is cheap to make, but will not handle the higher wattage bulbs in the average OHPs. The average and overkill OHPs use a transformer to reduce the voltage. My suggestion here is to leave it alone. For those who are daring and have no warranty on the OHP may wish to try and put a heat sink on the diode and upgrade the bulb. I'm curious as to how successful people are at this (I plan on trying it once my warranty runs out).
4. Extras - These include built in spare bulbs, built in outlets to plug in you panel / laptop, small form factor for easy transport, etc. Most of these are useless in a static configuration and if possible should be avoided to keep the cost down.

Make a couple of good quality screen shots of what you will be displaying on the setup. Get / borrow a laptop. Grab your panel and head on down to your local Audio/Visual Media store that sells OHPs (these are getting hard to find, but if I can find one in Winnipeg - you should be able to find one nearby as well). Ask them to setup 2 or 3 projectors - make sure one is a 2500 Lumen project (they will try to convince you that there is no way a Panel will look good on such a cheap projector - but that's why you are doing a side by side comparison). Place your panel on the projectors one at a time and see for yourself which is the best for your budget / requirements.

An audiophile CD-Player / Amp can really sound lousy if your only speakers are the $50 multimedia speakers from Radio Shack. The same holds for your projector - whether Panel / OHP or LCD Projector. Without a decent screen, the image just won't be as good as it can. Unfortunately I have not had the time or money to properly investigate a good screen, but I will suggest this from experience - a rough cement wall painted light blue pales in comparison to an old beat up portable screen designed for OHPs.

There are basically two types of screens. Front projection and rear projection.

These are white, silver or even grey. They are opaque (no light leaks out the back - and most are black on the back). Generally they are made of cloth, plastic or canvass so they can be easily rolled up and out of the way when not needed. For OHP they are almost always flat (not curved for wrap around effects) and generally fairly square with the longer dimension being vertical (just the opposite of monitors). Commercially available screens are not cheap! A good screen (especially one that is portable) can cost more then an lower end average OHP!!

These are made of a translucent material. Up close they look dull grey, feel rough and almost rubbery as if made from latex or neoprene. These are great for getting a large image right in your face! As the projector is behind the screen pointing at you, it is not consuming valuable real-estate in or around your pit. However, I suspect that they require much more light then front projection screens and may not be suitable for Panel / OHP setups.