The pressure-sensitive screen on the Apple Watch

Apple Watch.
A rendering of the Apple Watch by Justin14 [CC-BY-SA-4.0], via Wikimedia Commons.
Joseph Flaherty at Wired published an article today suggesting that the Apple Watch’s pressure-sensitive touchscreen might be a bigger deal than the Apple Watch itself. While I’ll let the market in the future determine the ultimate success of the product, I thought that Flaherty raised an interesting point with regards to the touchscreen user interface. Flaherty states that being able to sense a press with the so called “flexible Retina display” would allow for context-specific menus—much like the powerful “right-click” interaction with many computer interfaces. This could allow for a potential decluttering of the touchscreen interface because the user has a way of calling up menus that does not involve tapping on menu buttons or toolbars.

This decluttering could be useful for many, but may also be problematic for some. Context menus hide functionality, which some users may now not be able to find. In a poorly designed interface, people may have to “hard-press” many types of onscreen objects and elements to see which ones have the right hidden menu. In a well-designed interface, users would know just by looking (or convention) which onscreen elements have associated context menus.

An Accessibility Use of Pressure-sensitive Touchscreens

Having a pressure-sensitive touchscreen also allows for a very interesting and useful method of access for people who are blind and who have low vision: pressing firmly to activate an onscreen element. Currently, iOS and Android have built-in screen reading software. One way of using these respective screen readers is in an “exploration mode” where a user touches elements on the screen to have them read through text to speech. Because the system cannot different between a touch that means “what is this?” and a touch that means “activate this,” a separate gesture is needed to activate the desired element one found. On VoiceOver in iOS for example, the person double taps anywhere on the screen to activate the item that was last touched. This second gesture can be somewhat awkward and involves extra motions.

With a pressure-sensing touchscreen, this “activation gesture” would be much more intuitive. Instead of having to double-tap the screen, press an Enter button, draw a circle on the screen, or any other complex gesture, the user could simply press harder. In the touchscreen exploration mode, a light or regular touch means “what am I touching?” and a firm touch would mean “activate this.” This would be very powerful and intuitive to people who cannot see touchscreens well enough to read them.

Add-on tactile buttons for mobile devices

Just launched today as an Indiegogo campaign (and over a quarter of the way to the goal as I am writing this) is an interesting product idea called DIMPLE from Dimple is basically a sticker with 4 buttons that can be added to many Android 4.0+ devices that support Near Field Communication (NFC) and the Dimple app. It requires no batteries because it uses energy that is radiated by the NFC reader.

Photo of Dimple button prototype.
DIMPLE buttons on the back of a phone. (Photo from press release kit.)

This prototype product is not one made specifically for people with disabilities—obviously from the response on Indiegogo, many people are interested in having customizable, programmable tactile buttons on their smartphones and tablets.

Dimple has potential accessibility uses. Such buttons would be useful for people who cannot see, because the buttons can be tactilely discerned and located. These users could associate some of their most commonly used functionality with the buttons and access them directly, instead of having to navigate through menus with the TalkBalk screen reader.

I do not know the exact capabilities of DIMPLE, NFC, or Android TalkBalk, but it would be very useful if the Dimple buttons could be used to access the TalkBalk screen reader or to generate virtual keyboard keystrokes. If capable, it would be very useful to have dedicated buttons to navigate through applications and make selections. This would be less fatiguing than making many swiping gestures to navigate.

The Bradley Tactile watch

On Kickstarter until August 15, 2013 is the Bradley timepiece project. It is a wristwatch that has tactile features that allow it to be used by people who are blind. It has an elegant design and greatly surpassed its fundraising goals.

The Bradley Timepiece tactile wristwatch. (Credit: Kickstarter by Eone)
The Bradley Timepiece tactile wristwatch. (Image credit: Kickstarter project by Eone)

Before this design, there were two general approaches to accessible wristwatches: talking watches and tactile watches like the one pictured below. Talking watches may not be easy to hear in noisy environments. With traditional tactile watches, users must lift a cover, which protects the delicate hands of the watch face.

A tactile watch with the cover open (image available without copyright from Wikipedia Commons)
A tactile watch with the cover open (image available without copyright from Wikipedia Commons)

The Bradley does away with hands and has two ball bearings that are magnetically attached to the movement, which makes the watch more durable. The position of the ball bearing on the face denotes the minutes, while the ball bearing around the periphery of the watch denotes the hours.

The Bradley timepiece is a good example of a design which incorporates Universal Design or Design for All principles. Its popularity on Kickstarter is more a testament to the attractiveness of the design than strictly to its utility for people who are blind. Such a watch can be used by people with and without visual impairments. The titanium watch has a very elegant appearance. My only worry is how much the titanium would scratch with everyday use, but that is not an accessibility topic!

See more information at the Eone Timepieces website. The site has a very elegant design, but unfortunately and ironically, the site is not very accessible in its current form (and is thus not an example of Universal Design).

Low vision with the old and new iOS icons

Last week, Apple announced the largest user interface overhaul to iOS since the iPhone was first introduced (gallery and basic description of iOS 7 features). A number of posts and articles have been written recently comparing the new look versus the old and that of competitors.

In this post, I am going to take a different approach. I will not talk about the aesthetics, but instead about the accessibility to people with vision impairments. The flickr user nielsboey posted an excellent image comparing the icons for native applications in iOS 6 and iOS 7. With his permission, I have copied it here and made a blurred version to “simulate” low vision. Click on the links for a larger version.

Comparison of iOS 6 and 7 native application icons.
Regular icons.
Blurred comparison of iOS 6 and 7 native application icons.
Blurred icons.


To see some of the usability barriers one might have with low vision, blurring the display is a good test. Note that blurring is not a simulation of low vision. What a person with low vision might see varies depending upon the cause of their impairment.

There are other visual tests one can try. I used a Colour Blindness Simulator to look for egregious problems for people with color blindness. There was nothing particularly problematic with either the old or new icons.

Some improved icons

Blurred Camera icons.

Blurred Safari browser icons.

Blurred Contacts icons.

Several of the new icons (on the right) have improved for people with low or blurred vision.

For example:

  • The camera app icon now takes the shape of a traditional camera rather than just being an image of the circular lens on iOS devices. The camera shape can be made out more easily as a camera than a dark circle.
  • The Contacts app icon has been improved in iOS 7 because the silhouette of man on is much larger even though the contrast is somewhat decreased from that of the previous version.
  • The new Safari mobile browser icon is a little easier to find simply because it is a blue circle that looks like a compass rather that just a rounded rectangular blue field with small points or arrows.

Some old icons were better

Blurred compass icons.Blurred calendar icons.There are also examples of the new icons (right) being worse for people with low vision.

  • The Compass app icon used to be a light-colored compass face on a darker background. The new version is a line drawing of a compass on a dark background. The lines on the icon are so thin that they are difficult to see when blurred. The icon looks like a black square with rounded corners.
  • The new calendar icon uses a font with a much thinner weight or stroke width. While one can perhaps make it out while blurred, the old calendar icon, with a much heavier font, is much easier to read.

There is a current design trend towards fonts with very light weights and thin strokes. This is also apparent in icons that are simple line drawings with very thin lines. This trend has become possible now because screens on mobile devices are being made with very high resolutions. Thin lines and very light fonts are much easier to display at high resolutions. At lower resolutions, such thin lines would become larger and more block-like. The thin strokes of current design trends are more difficult to see and read with low vision.

Tactus tactile touchscreen prototype

Touchscreens can be particularly challenging to use for people who cannot see. All they feel is a featureless surface. Accessibility can be provided through speech using a number of different strategies, but finding onscreen buttons through audio is slower than finding tactile buttons.

Photograph of tactile bumps.

An edge view of a tactile layer that could be used as part of a touchscreen. (From Tactus Technologies.)

Tactus Technologies has been developing a touchscreen with areas that can raise and lower from the surface. Sumi Das for CNET posted a video and hands-on impressions a couple days ago. The technology uses microfluidics. For the buttons to raise up, liquid in the system is put under pressure–the higher the pressure, the taller and firmer the keys. The current version only offers one arrangement of buttons.

Currently, the technology is limited in that it’s a fixed single array. You wouldn’t be able to use the Tactus keyboard in both portrait and landscape mode, for example. But the goal is to make the third generation of the product dynamic. “The vision that we had was not just to have a keyboard or a button technology, but really to make a fully dynamic surface,” says cofounder Micah Yairi, “So you can envision the entire surface being able to raise and lower depending on what the application is that’s driving it.”


The current generation only offers a single array of raised buttons that would work in only one orientation. This would be helpful for allowing users to find the keyboard tactilely, for example, but this would offer no support for other applications. The user cannot tactilely find buttons or other controls for other applications on a smartphone or tablet.

Future versions may fix this limitation. Ideally, the microfluidic tactile “pixels” will be small enough so that various tactile shapes can be made. To make seamless shapes, the tactile pixels should not have significant gaps between them, but this may be technically difficult to do. With gaps in between the tactile pixels, the device could still be useful to tactile exploration, but the layout would likely be constrained to a grid of bumps. An onscreen button might have a single bump associated with it (multiple separate bumps should not be used to designate a single large key because it would feel like several separate controls). The bumps would allow people to locate controls, but without different shapes, it would be more difficult to identify the controls from touch alone.

From the video, it also looks that the current technology is not well suited to braille. Spots small enough for braille would not be sharp or tall enough for effective reading. (For more information, has a table of braille dimensions under different standards).