The guide gives contact details for some suppliers. This should not be taken as a guarantee of quality or endorsement. If you have had good experiences with other suppliers then do let me know and I'll mention them. Also some price estimates are given in British pounds sterling. At the moment there are roughly 1.88 US dollars and 1.46 Euros to the pound.

Buying a computer for a museum exhibit

What do I need to buy?

Museum computer exhibits can normally be divided into three main parts; the computer; the screen and some way for the visitors to control the exhibit such as a touch-screen. You'll also need some kind of housing to put the computer in. In this guide to buying a computer exhibit I'm going to look at each separately.

What type of computer should I get?

Computers are generally divided up according to what operating system they use. The three main types you might come across are Windows computers (also known as PCs), Macintosh computers and Unix (one variant of which is called Linux) computers. All of these types have many different versions and variants that I won't go into any more than you'll need. Here's the important stuff you need to know.

• Unix, including Linux computers should be avoided for kiosk use. Unix computers have two basic problems when being used for museum kiosks. Firstly very few of the tools used to make kiosks work with Unix - so you'll have real problems getting software to work with them. Secondly very few people have used Unix for kiosks so its very difficult to find people with the necessary skills. So unless you are prepared to write all the software yourself and do all your own support avoid these machines.
  
• Macintosh computers. Macintosh computers have been successfully used for many museum kiosks, but not by me. This means that although you can use Macintosh computers for your kiosk I won't be able help too much with technical details and suppliers.
  
• Windows computers. I have successfully used Windows computers in over 200 museum exhibits and although setting them up isn't always as simple as you'd like they can be made to work very successfully and if you follow the rest of this document you shouldn't have too many problems.
  There are many different variants of Windows, some of which are suitable for museum kiosks, some of which aren't. Variants to avoid are Windows 3, Windows 95, Windows 98, Windows M and Windows NT. Windows 2000 and Windows XP are fine. The next version of Windows, "Vista" will probably be ok as well but I'd avoid it for the moment until its established itself.

How do I know if the computer is powerful enough?

If you read adverts for computers they're full of lots of confusing specifications for describing how powerful the computers are. A few years ago I came up with a rule that The least powerful new computer you can buy today will usually run all museum exhibits without problems. This means you should just buy the cheapest one you can get that fulfils your other criteria. With more experience I would say that this rule still usually applies but it's always a good idea to build in some flexibility.

• If you are having your software specially written you should talk to who is writing your software before buying the computer. If the software uses a lot of video or 3-dimensional graphics they may like to specify a more powerful computer.
• If you're buying a PC make sure it has something called an "PCI Express extension slot". Most new computers have these - the only ones that don't are the ones with very small cases. Having this slot means that if your computer isn't quite fast enough you can speed it up by putting in a new graphics card quite cheaply rather than buying a new computer.
• Cheap computers are often sold without enough memory, adding more isn't that expensive - at the time of writing (2004) 512MB is a good amount to aim for.
  Sometimes companies sell off rather old computers cheaply which don't really have the power for the job. If you're choosing computers and you're not sure about the technicalities then it may be better not to buy the least powerful machine on offer - but the next one up is probably fine.
• If you do buy your computer before the software is written you should insist that the software is regularly tested on that computer during development so that you can be sure that it will work ok.

Where should I buy my computer?

As I've said above, the speed of a kiosk computer tends to be unimportant. So what matters when you're buying a computer for a kiosk? Well you may need some help setting it up in the first place but the other main concern is what happens if the computer breaks. My experience of exhibition projects is that funding for initial building is always far more plentiful than that for running costs and that any extra money or energy put into stopping things breaking or making them easy to fix is amply rewarded in the long run. So how do you do this? Here's some tips - you probably won't be able to follow them all but it gives you something to aim for.

• Buy from a company who know what they're doing. Ideally this should be someone specialising in kiosk type machines such who will set the machine up for you (as specified in Setting up a kiosk computer). If you're not confident you can find a supplier whose technical skills you trust you could go for non-specialist retailers with a reputation for customer service - such as John Lewis. I've heard bad things about high street computer retailers such as "PC World" and "Dixons" and the "extended warranties" they sell are generally a waste of money.
• Buy a computer with a brand you've heard of. No brand of computer is without problems but by buying from the likes of HP, Compaq, Toshiba etc you've stacked the cards in your direction.
• Buy local. For hardware its always useful if the supplier is local so if things do break you can take it back or they can visit with the minimum of fuss. I do remember one kiosk I was involved in that had been bought from another continent which took over 6 months to fix when it broke…
• Don't use second hand equipment. Second hand computers tend to be very cheap but unless your exhibition isn't supposed to be up for very long you should avoid them. The reason for this is that their components have already been used for some time and so are much more likely to fail sooner. Another reason for not going second hand is that you may find it impossible to get your software to run on an older machine.

At the moment (May 2006) I'm buying computers from Hewlett-Packard which I'm very happy with.

What type of screen should I get?

Almost all computer exhibits have some kind of screen to show what they're doing. There are two basic types of screen - CRT screens which are the traditional TV type screens and LCD screens which are the newer "Flat panel" screens which are becoming more popular. Each has its own pros and cons which I've listed below.

CRT

Pros

Cheap - they start at around 100 pounds
Good picture quality if you get a good make - the Science Museum uses Iiyama, but Sony are also known for the quality of their displays.
Robust - CRT monitors tend to be big heavy strong things which will take a fair bit punishment and are difficult to steal.

Cons

Take up a lot of room - you'll need a lot of space which won't make your exhibition designer happy
The physical size also means you generally need two people to install or remove one - which makes maintenance more difficult
The very cheap screens that get supplied with cheap "all-inclusive" computer deals tend to be very bad quality.

LCD

Pros

Small and easy to transport
Take up less room in your exhibition and can easily be fitted by one person
Good picture quality which tends to stay bright - some CRTs can get darker over time.

Cons

More expensive that CRTs - prices start at around 150 pounds but getting cheaper all the time
Less robust - LCD screens "squash" if you touch the screen, you should really try and get a screen with a glass cover to protect it. Also the small size means that unless you trust your audience utterly you should enclose it in some kind of housing to stop them walking off with the screen or unplugging it.
Viewing Angle - some cheap LCD screens have what is known as a small "viewing angle". This means that if you look at the screen from an angle the picture disappears or changes colour. This is fatal for a museum exhibit as you can't predict what angle people will approach it from. Make sure the viewing angle is at least 160° both horizontally and vertically.
Picture quality - some cheap screens don't have very good quality. Never buy without seeing the screen in action first.

Although this list seems to show LCD screens with more problems than CRTs unless you are really strapped for cash I would go with the LCD screen. As far as I'm concerned the advantages for exhibition design and maintenance outweigh possible problems.
You can also get very large LCD screens and there's another type of large screen called a plasma screen. Computer exhibits can also be connected to data projectors which project a display several metres high. Both of these methods are more complex than you might expect and if you're interested in using them I would approach an expert.

How big a screen should I get?

Screen size is measured, in inches, by the diagonal distance from one corner of the screen to the other (like TVs). There is a slight complication in that with a CRT screen the picture doesn't come up to the edges of the screen so if you want to know the actual picture size you subtract 2 inches from the quoted screen size - this doesn't happen with LCD screens so the quoted size is the picture size. What this means is that a 17 inch CRT screen has about the same picture size as a 15 inch LCD screen.
For most exhibitions 15 inches is a good minimum screen size, smaller than this and screens disappear into the background. Bizarrely they're also more expensive due to reduced demand. Above 17 inches the prices of screens roughly doubles for every extra 2 inches of size. This means that if you want the best for your money its best to stick to screen sizes of between 15 and 17 inches.

You can buy touch and normal screens from Datasonic Ltd , Iiyama, Dicoll Ltd or Pentranic Ltd.

Controlling the exhibit

Visitors have to have some way of controlling your exhibit, normally you use a keyboard and mouse to control a computer but touchscreens and trackballs are better for kiosks. There's also some other ways to consider.

Keyboards and mice

Although fine for everyday use using a mouse and keyboard to control a computer exhibit isn't really recommended especially if your audience is young or likely to be rough with your exhibit. Standard keyboards allow anyone with a hint of mischief to shut down your exhibit completely. They're also easy to unplug, susceptible to damage from liquids being poured into them and don't tend to look very good. It is possible to get robust custom keyboards made which have all the potential "mischief" keys removed and these can work quite well.
A mouse doesn't give a potential mischief maker the same potential for breaking the exhibit but they are too fragile and easily stolen to stand up to a hostile audience for long. Although more sedate organisations such as the V & A museum have used them successfully, in the Science Museum they last an average of about 15 minutes.

Touchscreens

A touchscreen can be fitted on most computer screens for an additional cost of around 600 pounds. The type which use "Surface Acoustic Wave" technology seem to be the most reliable and give the best picture quality on the screen. The actual technology for these touchscreens is made by a company called ELO. However, its not a good idea to buy the touch mechanism separately from the screen - buy a screen with one already added from one of the suppliers listed above under screens. Visitors find it easy to use touchscreens although the software must have special features build in otherwise it can be very difficult for them. Touchscreens are generally very reliable but do need to be kept clean, otherwise they stop working. The cleaning procedure is not always straightforward and its best to get your supplier to give you a lesson in the approved cleaning method.

Trackballs

Trackballs resemble a large ball that the visitor rolls around to move an arrow on the screen to control the exhibit. They're relatively cheap - under £100. Standard desktop trackballs aren't really suitable though as the ball is only held in place by gravity and there's nothing to stop visitors walking off with it. I've had good experiences with military specification trackballs which are built to a tougher standard. The other thing to watch out for with trackballs is to make sure they're firmly secured, if not determined children will wrench them around and break the cable to the computer.

Other methods

There are other methods of controlling computer exhibits and product designers seems always keen to design new and exotic control methods. However, there are 3 main problems these tend to face.

• Reliability. It is very difficult to make a novel control method which will stand up to repeated use and rough treatment - a typical situation. It takes a lot of engineering achievement to do this and in my experience those designers most capable of designing an attractive, usable interface are the most lacking in the engineering necessary to make things reliable.
• Usability. It's a sad fact but visitors tend to like what they know and are most happy with touchscreens and trackballs. Curiously those contractors who are best at making novel control methods reliable seem to be the worst at making them usable by visitors.
  
• Trackballs and touchscreens are standard "off the shelf" items which come with warranties, instructions and can easily be replaced. Novel control methods tend to have none of these things.

Having said that, I have had some success with arcade controls such as buttons, joysticks and steering wheels which are designed to be robust.

You can buy trackballs from CKS Ltd or Traxsys.
You can buy arcade type controls from Suzo Ltd.

Housing

You'll also need some kind of housing for your exhibit. What kind depends on your audience, your design aspirations and your budget.

Your audience will determine how much protection you need to give to your exhibit. In the Science Museum we have to protect our exhibits from being switched off, unplugged or removed. In more gentle environments this isn't such a big problem. I've seen computer exhibits just placed on tables with no problems. (Although I recently saw such a computer exhibit in a large London gallery which had had its mouse removed by kleptomaniac visitors). The amount of protection you need to give your exhibit will also depend on the amount of supervision you have - an exhibit next to a museum staff desk will need less protection than one in an obscure corner.

Assuming that you've decided that your exhibit needs protection, the cheapest solution I've seen is to put the computer in a cupboard, then put a touchscreen CRT on top of the cupboard. You then need someone to custom build some protectors that fit on the CRT to stop people unplugging the leads or switching it off.
If you feel this doesn't meet your design aspirations then you have the choice as to whether to buy an off the shelf kiosk or to get one designed and built yourself. An off the shelf kiosk is definitely the easier option. The Science Museum buys kiosks complete with computer and touchscreen for about £3000 pounds from a company called Datasonic. Having a custom housing designed and built is definitely more complex. If you do here are a few technical constraints to bare in mind:

• If you put a computer in a sealed box and run it all day it will get too hot and stop working. If you have one or two computers in your housing make sure that they have plenty of room round them for air flow and that the housing has venting (top and bottom, just at the sides is no good). If you have more than two computers in your housing you'll need to install cooling fans.
• Assume that every part of your computer exhibit may break and need replacing by a single unskilled worker. Many computer housing designs I've seen assume a skilled team have at least day to replace broken parts - this is asking for non-working exhibits.
• Computer leads are surprisingly large and many designers ignore them in their designs and make no holes for leads or make the holes too small.

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© Joe Cutting 2003-2005. You are welcome to use this document for your own purposes but you must retain this acknowledgment. You may not sell all or any part of this document or use it for financial gain.