There are three major types of touch screen technology: pressure-sensitive, electrical contact, and optical field. I'm going to ignore the fact that some screens use more than one type of sensing. Let's step through.
(1)
Pressure-sensitive touch screens are generally older and smaller. You must apply pressure to the screen to activate. Any stylus can work, but a stylus applies pressure differently than a finger and such screens may not respond well to a stylus without adjustment, and possibly not at all. You may also need too much pressure to be practical or safe.
(2)
Electrical contact ("capacitance" or "P-Cap") screens are the most familiar these days since almost all smartphones and pads use them. These are common on touch screens up to about 32". These require electrical contact, but no pressure. Fingers conduct electricity. Not all plastic styluses do. For a stylus to work, it must conduct electricity. This type of stylus is now common, but they cost more. Unfortunately these screens are also commonly "multi-touch" and single stylus can't "pinch" to zoom.
(3)
optical field (generally "IR"). Most touch screens larger than 32" (but not all) use a grid of light beams. When you lower a finger to the screen, you break the grid, triggering the touch. This grid actually hovers over the screen so technically you don't have to touch the screen at all. These screens are commonly triggered by docent badges swinging near the screen. These screens can be operated with any object, including any stylus. Like IR, these are commonly multi-touch.
Unfortunately, I'm not optimistic about styluses in the long run. I see them as an interim solution. They are simply not convenient. In addition to the above issues, styluses are an accessibility barrier because they require more dexterity. A dropped stylus on a slanted optical screen may roll into the sensor frame and get stuck disabling the screen until it is removed. And finally, I predict they will become a cleaning problem, rolling into cracks are rattling around in vacuum cleaners.
But they are a quick and easy solution for many problems right now and possibly more than sufficient to get many exhibits back up and running.
Cheers,
tod
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Tod Hopkins
Technical Director
Hillmann & Carr Inc.
Washington DC
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Original Message:
Sent: 06-03-2020 03:21 PM
From: Joel Conrad
Subject: Styluses for "touchless" digital interactives
Robin, I don't have answers for your questions, just a quick note.
Make sure you test the styluses on all your touch screens.
We have close to 70 interactive touch screens. They do not all use the same technology.
We've found about 25 percent that do not do well with the cheaper style of styluses.
We've reached out to the manufacturers for help. Some have sent us software to modify the screen's sensitivity.
Others have recommended expensive (>$8) styluses.
We've not had a chance to test the modifications.
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Joel Conrad
Audio Visual Technician
Museum of the Bible
Washington DC
Original Message:
Sent: 06-02-2020 07:22 PM
From: Robin Faitoute
Subject: Styluses for "touchless" digital interactives
We plan on providing our guests with free styluses upon reopening--so they can safely engage with our many digital interactives. In keeping with our conservation mission, we are inviting guests to help us recycle the styluses by returning them to us when they exit. Does anyone have experience with, or recommendations for, sanitizing aluminum and plastic, rubber-tipped styluses?
Any advice is greatly appreciated.
Thank you,
Robin
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Robin Faitoute
Manager of Exhibit Development
National Aquarium
Baltimore MD
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