Pen computing returns: Revenge of the stylus

For many years just about every portable device came with a stylus. Whether it was the revolutionary Eo Slate with its PenPoint OS, the doomed Apple Newton, the very successful PalmPilot, or Windows-based PDAs, a tiny stylus was necessary to navigate the shrunken version of applications they ran. Even the Tablet PC was tied closely enough to the stylus that the wave of computing it was supposed to usher in was called “pen computing.”
In 2007, the introduction of Apple’s iPhone changed all that. Suddenly there was a hot, new device that you could operate entirely with your ungloved finger. Stylus-based interfaces like Windows Mobile became extinct in record time. Fingers were the new mice for mobile. True stylus believers were stuck with cheesy capacitive pseudo-fingers that allowed them to smush things around on the screen. No matter how well-designed, capacitive styli are limited by the typically low resolution and lack of pressure-sensitivity of capacitive touchscreens.
To put my cards on the table, I’m a card-carrying member of the “I like to use a pen” school. As a photographer, I have several different Wacom tablets I use for Photoshop on the desktop. As a tech journalist I really wanted to find a tablet-based solution  for note-taking during talks and interviews that would let me ditch my reporter’s notebooks. Capacitive stylus solutions, no matter how stylishly shaped, just didn’t cut it for me. Fortunately, I wasn’t the only one. The last couple years have seen a major revival in stylus-based products — bringing back the promise first offered by “pen computing.”

Samsung uses Wacom for stylus-centric innovation

Samsung gets a lot of grief (and lawsuits) for imitating other firms’ good ideas. In the case of active-stylus-based mobile computing, though, they have led the way with their extensive Note product line. With over 40 million units sold, a combination of large screen and note-taking capability has made the Note phablet one of the most popular high-end mobile devices. It’s bigger sibling, the Note 10.1, has remained a niche product for die-hards like me, but definitely has a loyal following.
By using an active stylus in the Note, Samsung achieves several major advantages over a passive-stylus-based version. First, it is easy for applications to tell the difference between the pen and touch. That means that you can rest your hand or accidentally touch the screen while writing with the pen and not have it mess up your ink. Second, you get very high resolution to enable precision note-taking and drawing. Third, it is possible to detect the stylus even when it is only hovering over the display, allowing for some cool added features. Finally, you also get pressure-sensitivity, allowing more accurate modeling of different drawing and painting tools.
For the active stylus in the Note, Samsung — and later Microsoft — turned to leading tablet vendor Wacom to add the necessary sensing layer. Wacom uses Electro-Magnetic Resonance (EMR) technology to generate a small magnetic field that creates a resonance in the pen’s other wise passive (non-powered) circuitry. Along with position, the sensor board receives data including the pen’s speed, angle and writing pressure.
The downside of EMR is that it requires a separate layer of small antennas and a lower shield to block interference from other components. This can add as much as a millimeter to the thickness,  as well as to the weight and cost of Wacom-power devices — although the newest generation of Note products show that even EMR-equipped displays are getting thinner and lighter over time. A separate controller is also needed to turn the magnetic fields on and off based on pen location. Since fingers and capacitive styli don’t have the same resonant circuits, the EMR sensor doesn’t see them at all.
Wacom also has their own active-stylus tablets now — the Cintiq Companion product line. Cintiqs are clearly the king of stylus-based input. They’ve delivered high-quality pressure-sensitive input on a screen for years — but high-cost and dependence on PCs made them a special-purpose tool for well-heeled creatives. Now Wacom has extended the Cintiq product line to mobile, or at least portable, devices, with its Cintiq Companion products, available in both Windows 8 and Android versions. Their large size and high price tag will keep them out of the hands of all but a few, though.

Can n-Trig and Sony unseat Wacom’s spot as stylus king?

Wacom has been the gold standard in consumer and creative professional stylus-based computing for a long time. Its market-leading performance comes with a high price in cost and weight though. Embedding its FEEL active stylus technology has driven up the cost, size and weight of devices like the Samsung Note  and Microsoft Surface Pro that use it. Israeli-based n-Trig is trying to change all of that with its DuoSense technology — featuring a single integrated controller that handles both touch and pen input.

Sony, HTC and now Acer have partnered with n-Trig to add what they call Active Pen capability to several of their products. Active Pen — based on n-Trig’s DuoSense controller — natively supports using both touch and pen simultaneously, and features integrated palm rejection. According to n-Trig, all that is accomplished with essentially no added cost or weight over competitive touch-only solutions. Because it is a single integrated controller, DuoSense also allows for thinner devices, with less distance between the pen and the sensor. This helps reduce parallax — an annoying condition where ink doesn’t appear directly under the pen as viewed by the user.
As an avid stylus user, I’m very aware of is parallax. With EMR-based devices, because the stylus-sensing layer is below the LCD and touch controller, it has to guess a little on where to show the ink, depending on the angle of the pen and what it calculates is the likely viewing angle. This tends to be made worse for left-handed users like me, as the default behavior is to try to minimize the effect for right-handers. Some applications let you tweak the way they handle parallax, but most don’t. Because the n-Trig stylus sensor is integrated into the touch controller, the whole system is thinner, and the problem of parallax is greatly reduced.

Head to head with Wacom and n-Trig’s Active Pen

n-Trig’s combined touch and pen controller almost sounded too good to be true, so before writing about it I wanted to try it myself. I put together a side-by-side test of a Wacom-enabled Microsoft Surface Pro and Samsung Note 10.1 2014 Edition to compare with a Sony Duo 13 equipped with n-Trig’s Active Pen. The first thing to note is that all these devices are head and shoulders above using a simple capacitive-based touch screen with a passive stylus. Especially with the current generation hardware they all feature, inking was smooth and responsive. Even fairly fancy brushes rendered precisely and promptly.
For a handwriting test I used MyScript Notes Mobile, since it available on all the devices and supports pressure sensitivity. They all worked essentially flawlessly. The Samsung pen is tiny and hard to hold — so that it can fit inside the tablet — but there should be after-market styli that work with it available soon (As a cautionary tale, the Styli sold to work with the older Samsung Notes have significant parallax when paired with the newest Notes, so updated stylus models are needed). The only real difference I noticed between the Wacom-powered tablets and the n-Trig version was that the Active Pen didn’t feel quite as paper & pen-like as the Wacom models, but n-Trig has an updated design in the works that improves the feel — making it nearly like writing with a ballpoint pen on paper.
The thinner design of the n-Trig controller essentially eliminates parallax. Indeed, compared to the slight parallax I saw with the Surface Pro, the Active Pen was flawless. However, so was the newer Wacom-based design incorporated into the Note 2014 Edition, so it isn’t only n-Trig that has been innovating with thinner models to improve usability. It is clear that both Wacom’s EMR technology and n-Trig’s DuoSense controller can deliver nearly perfect pen-based interaction. n-Trig also offers simultaneous touch and pen input, along with reduced cost and weight, so I’d expect to see it adopted in additional systems as mobile device vendors look for an edge in the very competitive markets for smartphones, tablets, and ultrabooks.

Nvidia’s clever computational stylus

In an amazing tour de force of computational power, Nvidia has harnessed the power of the Tegra GPU to essentially emulate the precision of a true high-resolution, pressure-sensitive stylus by using a version of computational imaging along with an inexpensive capacitive stylus in its Tegra Note product. So far I’ve not been able to test the Nvidia solution hands-on, but if it has figured out how to emulate the features of an active stylus with processing power — and not paid the price in slower response times or more battery drain — Nvidia may raise the bar yet again and pave the way for the stylus to make a return to prominence in mainstream devices.

Attack of the Bluetooth styli

With the market-leading iPad stuck with only a capacitive touchscreen, it isn’t surprising that several vendors have pushed the envelope to innovate with pen solutions that don’t require a screen redesign. Adonit’s Jot and Wacom’s own Intuos Creative products combine an accelerometer and a Bluetooth transmitter in the stylus itself to precisely track stylus motion on your phone or tablet. Since they are an add-on, only applications that have been specially modified to use these styli will take full advantage of their buttons and pressure sensitivity. A similar issue exists with startup FiftyThree’s new Pencil stylus, also based on using Bluetooth LE, but optimized to work with the company’s own very popular Paper application on the iPad.
The good news for stylus-junkies like yours truly is that pen-based computing is finally becoming possible on industry-leading devices at reasonable cost. Whether it is a high-end solution from Wacom, or a hybrid from innovative n-Trig, active stylus products are available across almost every mobile product category. For the rest, increased compute horsepower and low-energy Bluetooth are making novel new approaches like those from nVidia and iOS add-on makers viable. Now the industry needs to drive some standardization around pen APIs and ink-based note taking file formats for pen-based applications to catch up with the hardware.

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