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Not All Tablet Styluses Are Equal: Capacitive, Wacom, and Bluetooth Explained

tablet-stylus-technologies

More and more Android and Windows tablets are advertising their styluses. They’re popular iPad accessories, too. But not all styluses are equal. The technology built into your device’s touch screen will control what kind of styluses you can use.

Knowing the difference is important when shopping for tablets. For example, if you’re a digital artist, a Surface Pro 2 offers a much better stylus than a cheap Dell Venue 8 Pro, even though they may both be advertised as having styluses.

Capacitive Stylus

Your modern touch-screen device uses a capacitive touch screen — unless it’s a Wii U GamePad, which still contains a resistive touch screen. That’s why you can simply touch the device’s screen, while you have to press down on older resistive touch screens like those on the Wii U GamePad and traditional touch-screen ATMs.

The cheapest, simplest type of stylus you can get is a capacitive stylus. A capacitive stylus works in the same way your finger does, distorting the screen’s electrostatic field when it touches it.

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All you really need to know is that a capacitive stylus will work just like your finger. They’re simple to make — you can even make your own capacitive stylus with a bit of wire and conductive foam.

Pros:

  • Works with any device: As long as your device has a capacitive touch screen you can use your finger to touch, you can use a capacitive stylus with it.
  • No battery required: You won’t have to charge a capacitive stylus or change its battery.
  • Cheap: As they’re so easy to make, these will be the cheapest types of styluses. You can even make your own.

Cons:

  • No pressure sensitivity: Just as your device’s touch screen can’t sense how hard you’re pressing on it with your finger, it can’t sense how hard you’re pressing on it with a capacitive stylus. Artists who want a pressure-sensitive stylus won’t be happy with a capacitive stylus.
  • No palm rejection: The capacitive screen can’t differentiate between the stylus and your hand, so you can’t rest your hand on the screen as you use the stylus to draw.
  • No additional functions: You can’t have a capacitive stylus that performs other functions, such as having an eraser on its other end. It functions exactly like your finger.

capacitive-stylus

Wacom Digitizer

Wacom makes drawing tablets for artists, but this technology is also making its way to consumer devices. For example, Microsoft’s Surface Pro includes a Wacom-made digitizer layer in its screen and a pen made for it, known as the Surface Pro Pen. Samsung’s Galaxy Note and its S Pen also use Wacom technology.

By integrating a special sensor into the touch screen and designing a stylus to work well in it, Wacom digitizers offer a variety of features you can’t get with a capacitive stylus. Note that the exact level of pressure sensitivity will vary from device to device; be sure to do research about the specific device you’re looking at.

Pros:

  • Pressure sensitivity: The most important feature that a Wacom-based digitizer layer offers is the ability to detect different levels of pressure. For example, Microsoft’s Surface Pro Pen advertises 1024 levels of pressure. The screen doesn’t detect how much pressure you’re putting on it — instead, the tip of the pen retracts as you push down harder on the screen, and the digitizer layer can detect a difference in signals.
  • Palm rejection: When you’re using your stylus to draw on your screen, the tablet can perform “palm rejection,” ignoring your touches and allowing your palm to rest on the screen.
  • Additional features: These types of styluses can just do more things. For example, the Surface Pen has an eraser on the other end, and flipping it over and rubbing the eraser on the screen will send an “erase” signal so you can erase things you’ve drawn in drawing applications. Holding a button on the pen and tapping the screen will perform a right-click. The digitizer layer can also detect when you’re hovering the pen over the screen, allowing you to perform hover actions.
  • No battery required: The stylus doesn’t need to include a battery, so you won’t have to worry about charging it.

Cons:

  • Supports fewer devices: Such styluses won’t work with all your devices. For example, a Surface Pro Pen doesn’t work at all on a typical phone or tablet.
  • Adds cost: Wacom digitizers are specialized hardware and only found on higher-end devices like the Surface Pro and Galaxy Note, as they make the device more expensive to manufacture.
  • Requires app support: Applications must be coded to detect this information. For example, you won’t be able to use different levels of pressure in Microsoft Paint.

wacom-stylus-pen-tip

Bluetooth Stylus

The types of stylus technologies above represent two extremes. One is no more advanced than your finger, but is cheap and works with almost everything. The other is an advanced technology, but requires special hardware and will only work with a few devices. Wacom-based styluses don’t even work with Apple’s iPad, and there’s clearly a demand for pressure-sensitive iPad styluses.

Thus, we have a third type of stylus that communicates with a tablet in a different way. Rather than requiring an entirely new hardware layer to detect pressure, the stylus communicates over Bluetooth with a tablet.

Such a stylus will function as a normal capacitive stylus by default. When you “pair” it with your tablet as you would another device, it will talk to the tablet. The touch screen knows where the stylus is touching, but it can’t detect the pressure. The stylus detects the level of pressure on its own and transmits this information wirelessly over Bluetooth when it detects it’s touching the screen, essentially saying “Hey, that touch you’re detecting — I’m doing that, and here’s how hard I’m pressing.”

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For example, Wacom makes their own pressure-sensitive stylus for the iPad, known as the Intuous Creative Stylus. It costs $99 and offers 2048 different pressure levels. As the iPad doesn’t contain a Wacom-designed digitizer, this stylus pen communicates over Bluetooth. Luckily, such styluses can use Bluetooth Low Energy for much longer battery life.

Pros:

  • Pressure sensitivity: Like a Wacom digitizer layer, such styluses can offer pressure sensitivity.
  • Palm rejection: Bluetooth styluses can also offer palm rejection.
  • Works with more devices: Such Bluetooth pens can be used to use a pressure-sensitive pen on an iPad, even though the iPad only contains a capacitive screen with no pressure-sensitive sensor layer.
  • Shortcut buttons: The stylus can send a signal over Bluetooth when a button is pressed, allowing for shortcut buttons on the pen.

Cons:

  • Battery required: As the device must communicate over Bluetooth, it must be powered. You’ll have to charge the stylus or change its batteries occasionally.
  • Pairing required: As a Bluetooth device, this type of stylus must first be “paired” with your tablet to use it. Ideally, this will only need to happen once.
  • Apps must be written to support the stylus: Apps must know how to interpret the stylus’s signals or they won’t know what to do about the pressure information the stylus is giving them.
  • More expensive: Bluetooth styluses will obviously be more expensive than a capacitive stylus, as they have to contain actual electronics.

wacom-creative-stylus-for-ipad-web-page


Bear this information in mind if you’re shopping for a new tablet and would like a stylus. Check the details — if the tablet offers a stylus, does it contain a Wacom digitizer layer to offer pressure-sensitivity, like the Surface Pro? Does the manufacturer-designed stylus simply use Bluetooth, as the Dell Venue 8 Pro’s does? Or is a sneaky manufacturer simply throwing in a capacitive stylus and calling it a day?

Be sure to do all of your homework, too — not all Wacom digitizer layers built into devices are equal, nor are all Bluetooth styluses.

Image Credit: André Luís on Flickr, William Brawley on Flickr, Bill G. on Flickr

Chris Hoffman is a technology writer and all-around computer geek. He's as at home using the Linux terminal as he is digging into the Windows registry. Connect with him on Google+.

  • Published 12/9/13

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