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Technical design

The challenge for technical designers is to make an interactive that is usable by as many people as possible.

Can you reach and use it?

Microscopes:

A conventional microscope, set on a 28 - 30 inch high table, is generally not usable by someone seated in a wheelchair. Twenty eight inches of open space under a table accommodates a wheelchair user’s knees but puts the eyepiece too high. If the microscope is lowered, the wheelchair user can't get his/her knees under the table. A successful solution is to tilt the microscope and mount it on a table, ideally with height adjustment capabilities. An adult, seated on a stool or in a wheelchair, can use it. A standing child can use it. And it can be raised to accommodate a standing adult. However, our maintenance staff has had some problems with the crank. People think it’s a focusing mechanism, crank it beyond its limit, and break it. A simple angled table with adequate knee room and depth works almost as well. Refer to the Maintenance section for more information.

Microscopes on a level counter with a solid base - Not accessible to wheelchair users		Wentzscope set on an angle, at a fixed height; - Accessible to most wheelchair users		Wentzscope set on an angle, adjustable height; - Best accessibility for wheelchair users

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Computer Interfaces:

Computer touch screens are a challenge for people with limited hand and arm strength and coordination. Many people with motor control issues can’t target and touch a specific, often small screen area. Instead of touch screens, we regularly use a large (3 inch) trackball and a large, easy to push "enter" button. These are set about four inches from the front edge of the table, to allow someone to steady his/her hands during operation. The Museum uses buttons and trackballs made by Happ Controls, a company that makes controls for use in arcades and other heavy use public settings. Their products are durable. Try their site for more. http://www.happcontrols.com

A touchscreen computer interface in "Current Science and Technology"		An Idea Exchange in Investigate! with a trackball and button interface

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Manual Controls:

Delicacy is out - big & easy is in!! We avoid controls that must be operated with thumb and forefinger or by placing one finger in a little indentation. Handles need to be graspable with a whole hand, or even better - operable without grasping. Buttons and switches should be of adequate size, and generally easy to operate. We use 3/4 in Happ buttons and, sometimes, paddle-like toggles. Toggles (1.5 in.) are easy to use, but they tend to break easily. We either cut them down to 3/4 inches or substitute two triangular buttons, one facing up, the other down. Large buttons are not only easy to operate, they also can accommodate helpful pictorial cues.

The Spin Browser in the "Big Dig". Put your finger in the indentation to turn the wheel		Wentzscope with large sample wheel, large "Light On" button and a manual crank mechanism to adjust height. The Montshire Museum in Norwich, Vermont has replaced the round focus knob with a larger scalloped knob - easier to manipulate

Visitors with visual impairment: Accommodating this audience is a major technical challenge, and very much a "Work In Progress" at the Museum.

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Smell delivery systems:

Smell delivery systems in use at the Museum of Science range from elaborate, (The pneumatic relay controlled atomizer in "The Observatory") to simpler (the fan-powered delivery system in "New England Habitats") to still simpler (a bellows setup used in "Secrets Of Aging") to simplest (closed receptacles with a "sniffing tube", in the "Messages" exhibit). The two most complicated systems are the most difficult to maintain. The other two are easily maintained. The simplest works fine, but depending on the odor, you may need the increased airflow provided by one of the other systems.

Atomizer in Smell Survey; "The Observatory"		Smellbox in "New England Habitats"		Smellbox in "New England Habitats"		Smell device in Do Smells Sell?; "Messages"

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Computer adaptations:

We navigate visually impaired users around a computer program by a system of button pushes (no trackball). For some activities , we use different size and shape buttons to help distinguish different functions. Augmenting this system, a consistently placed "audio help" button and earphone provides description, instructions and explanations specifically for visitors who are blind.

Words Plus in "Messages" - Are You Talking To Me?? Word intonation and emphasis		Words Plus in "Messages" - Watch Yourself!! Body language and facial expression

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Adapted Touchscreens:

There is technology which adapts touchscreen presentations for visually impaired users. We haven’t tried it and can’t comment on it, but it is in use at the National Museum of American History, in a temporary exhibit on the history of the Disability Rights Movement. For more information, visit http://www.americanhistory.si.edu/disabilityrights or contact Katharine Ott, the exhibit’s curator (ottk@nmah.si.edu).

An exhibitor at the ASTC 2001 conference was demonstrating a touch-screen based "exhibit browser" which can switch between a standard format and one which is accessible to visually impaired users. LINK www.enhancedrealities.com; Tel(256)704-5520.

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Can it reach you? - making content accessible

Computer interfaces:

The adaptations described above are avenues to intellectual access for visitors with visual impairment. Indeed, unless we come up with successful computer adaptations for this audience, they will be increasingly excluded from the increasingly computer-oriented exhibits favored by museums.

Audio delivery systems:

An exhibit that employs touch, smells or sounds is ideal for a visually impaired visitor, but only if supported by audio. Sound provides context to an exhibit’s content for this audience. Without audible explanation/description/ instruction, the blind user has no idea what he or she is hearing, smelling, touching and may not even know that it is there. Sound also offers a choice to everyone else. (It appears that many people would rather listen to than read labels.)

The Museum of Science uses a variety of sound delivery systems, depending on the exhibit environment and other factors. In the "Messages" exhibit, for example, great efforts were made to include people with visual impairment. Consequently, there is a high level of sound in a relatively small enclosed space with a terrazo floor. (Carpeting is precluded in that area because of a potential flooding problem.)

Dome speakers: To contain the sound, we use Brown Innovation dome speakers over many activities, most often to provide general content information. Similar products are available through other manufacturers.

Dome speakers control sound pollution in "Messages" Introductory Corridor

Dome Speaker makers:

Brown Innovations; http://www.purestereo.com

Secret Sound speakers; http://www.museumtools.com

Message repeater/handset: Instructions and descriptions specifically for blind users are accessed via a handset, activated by an "audio help" button. Messages are recorded on a digital ELK 124 message repeater. The system is flexible and relatively low cost. Twenty, 60 or 120 second messages are easily recorded and revised. A new version is expected in early 2002, which will have 8 channels, of one minute each.

Elk Products; http://www.elkproducts.com/products/elk-124.htm

Small speakers mounted on the activity: Short bursts of sound that are part of an activity, eg a dog barking or siren wailing, come from small speakers on the activity.

Audio tours at the Museum of Science:

The Museum has created its own (cassette tape) audio tour for visually impaired visitors to the Investigate! exhibit. For "Leonardo Da Vinci: Scientist, Inventor, Artist," a travelling exhibition, a random access CD guided tour was produced by Antenna Audio Tours.

Antenna Audio Tours,

PO Box 176,

Sausalito, CA 94966

415/332-4862

A guided tour and tactile map of the "Messages" exhibit, produced by TouchGraphics, is available at a stationary kiosk at the exhibit entrance. The Investigate and Messages tours were specifically created to accommodate visually impaired visitors.

Other audio tour resources:

Acoustiguide http://www.acoustiguide.com;

Voxsys Audioguides, http://www.voxsys.net Tel: 418/654-1115

Enhanced Realities, http://www.enhancedrealities.com

Measurements:

Rulers can be made tactile. Digital readouts of temperature or weight can be purchased with speech output. Captek/Science Products Box 888, Southeastern PA 19399 800/888-7401
	Tactile ruler on the roll-down track in "Investigate"

Making the audible visible - captioning:

All video programs are captioned for visitors with hearing impairments and anyone else who prefers text over audio presentation. In a noisy space, that can be a lot of people! WGBH, Boston operates a Caption Center; http://www.wgbh.org/caption

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Can you locate it? - Wayfinding devices

Talking signs, audio tours and audible "attract" screens.

Talking Signs

We are experimenting with a "Talking Signs" wayfinding system for visitors who are blind. This infrared system will guide visitors from the front lobby to three exhibits, and navigate them through two of them. (The third is too noisy for this technology to be useful) We will keep you posted via this website, as the project goes forward.

The "Talking Signs" system is currently in use, in conjunction with a digital random access audio tour for blind visitors, at the Mashantucket Pequot Museum, in Mashantucket, Connecticut.

"Messages" Talking Map kiosk

At the entrance to "Messages", a wayfinding kiosk helps visitors with visual impairments find their way around the exhibit. Users can access a tactile talking floorplan of Messages, or listen to a virtual audio tour of exhibit activities. The Messages kiosk has been developed by TouchGraphics. Blind/visually impaired visitors are led to this kiosk from the Museum lobby by the "Talking Signs" infrared wayfinding system (see above).

Talking Map kiosk outside "Messages"		Close-up of map

We are aware of only one other wayfinding kiosk for blind users. It is in Pennsylvania Station, in New York City. The kiosk was also developed by TouchGraphics, in conjunction with the Computer Center for Visually Impaired People at Baruch College in New York City.

Audible "attract screens" have been suggested by several visually impaired advisors, butcare must be taken because they add to the ambient noise. (See The Juggling Act, below)

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The juggling act

Sound Related Issues

User Control -

How much audio? How much repetition? Should there be a way to turn it off? - both for people who don’t need it and for people who have gotten the hang of it and don’t want to listen to any more instruction. To help us address these questions, we consult with several visually impaired advisors and incorporate many of their suggestions into the exhibit design. Sometimes our efforts at flexibility are successful, as in these examples in Messages:

• "Do Smells Sell?" and "Language To Go" have an optional "Audio Help"/Hearphone button
• "Extra Audio ON or OFF" offers alternative paths in computer programs for "Get The Picture?" and "Meaning With Music"
• Ability to move ahead, back up or proceed to another menu choice is built into the "Talking Map" kiosk

Sometimes our attempts at flexibility result in complication and confusion and we have to back off.

Sound pollution -

Depending on the space, audio labels, audible "attract" screens and content-based sound can make for a noisy environment.

In Messages, a 1600 sq ft enclosed space with 12 foot ceilings and a terrazo floor, we have had to turn off the musical component of the "Meaning With Music" attract screen. Similarly, an attract message for another component, "Get The Picture?" is very hard to hear when the exhibit is crowded. While carpeting and other sound absorption treatments could reduce sound problems, we were unable to carpet the floor in Messages, due to a potential flooding problem in that space.

To contain sound in Messages, we used dome speakers and hearphones. Sometimes, however, we had to use small speakers mounted on exhibit units. Each approach has its advantages and disadvantages. Dome speakers are the most expensive. They cut down on, but do not eliminate spillover noise. On the other hand, they require little maintenance. Mounted speakers are inexpensive and also low maintenance, but they contribute greatly to noise pollution. Hearphones are relatively inexpensive, but require a lot of maintenance. Moreover, devices that have to be held to the ear are not useful in activities which require a visitor to use both hands.

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Comments of a Technical Designer, on sound management

Type of Flooring. Hard floors reflect. This may require you to turn up the volume of the dome, thus adding to sound reflection ...and so on.
Type of room. A room’s size, type of walls and ceiling height affects not only the dome’s performance but the ambient room noise.
Component proximity to reflective surfaces. Walls, other exhibits and other solid objects all contribute to sound reflection. This is not usually much of an issue except if the component itself has hard reflective surfaces that bounce the sound back at the visitor.
Sound domes - There are several makers with different designs. Some do not focus as tightly and some have a very tinny sound. We use Brown Innovations.
Special processors. Some dome units are available with a special amplifier or processor. This is generally recommended because that is how the speaker was designed and tested to meet the manufacturer’s specifications.
Height from floor. Most units focus the sound at a certain distance from the floor. Different height people will be at different distances from the focus point. If the speaker is mounted at a height that focuses the sound for a sitting person, the differences will be minimized. Mounted lower, the domes will take more abuse because they can be touched. So far we have not experienced damage to the domes.
Use in traveling exhibits: Special packaging is required for travel.
Other sound delivery systems
Headphones have proven the best isolator and can usually provide the best quality of sound. They are also the most fragile, least sanitary.
Isolation booths offer better quality and isolation, but are costly, take up space, and prevent moving the component easily. They also present problems of wheelchair and scooter access. Iso booths can use simple equipment.
Hearphones are more durable, but sound is poor. They cost more than headphones, but are easier to use, stay cleaner and work better for people with behind-the-ear hearing aids. On the minus side, they have to be held to the ear, thus taking one hand out of circulation. In some instances, this would cause problems for blind visitors who explore tactile elements with both hands.
General speakers are the only good way to address several visitors at a time. They work best if there is a back wall to the component. You have to make the nearby items of an absorbing material or you get sound reflection off the wall and that can add confusion and distraction. Speakers aimed down will work better, but can bounce sound off hard floors. Speakers can be set into the table top, but that allows people to rest objects, or their arms on them, thus blocking the sound. Also, mounted in that position, they become good cups for spilled soft drinks. When using speakers you have a wider variety of prices and quality, but once you cut a hole for them, you need exact replacements.

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Pros and Cons

Cost and availability of sound delivery systems. Domes take time to order, headphones do not. Speakers can be easy to get if purchased from a chain, but take more space if larger model is used. Hearphones and headsets require holders and are often left on the floor. Also, cable length can be lead to tangling or a tripping hazard
Other deciding issues - Mono or Stereo?
Replacement - do you repair or replace damaged speakers?
Headsets - range from $15 to $150. Durability is one reason for the cost margin.
Theft - is another issue to consider: not only the choice of speaker but the form of mounting.

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