The secret of iPod's scroll wheel

Ask iPod users what they like the most about the device, and most will probably mention the scroll wheel. MP3.com's Eliot Van Buskirk has the story behind it.

Eliot Van Buskirk
Evolver.fm Editor Eliot Van Buskirk has covered and occasionally anticipated music and technology intersections for 15 years for CNET, Wired.com, McGraw-Hill, and The Echo Nest. He is not currently an employee of CNET.
Eliot Van Buskirk
4 min read
There are many reasons to like the iPod. But to me, the most compelling one is the scroll wheel.

There's never been anything better for negotiating the prodigious amounts of music that we're lucky enough to be able to fit into our pockets these days.

The iPod's scroll wheel has been through three iterations. The first one actually rotated; then there was the touch-sensitive one; and finally there's the clickable one found on the iPod Mini and fourth-generation iPod. I'd always assumed that this bit of design genius sprang from Apple Computer's labs. But in fact, I discovered that a company called Synaptics, which primarily makes touchpads for laptops, actually perfected this little piece of navigational heaven, in accordance with Apple's stringent design requirements.

Although you probably haven't heard of the company, there's a more than 70 percent chance that any touchpad notebook you've ever used was made by Synaptics. You probably noticed that when you moved your finger more quickly across the touchpad, the mouse moved more quickly across the screen. The iPod's scroll wheel works via the same principle, which is one reason it's so effective at blasting through long song lists.

The lightening-style patterning looks so good it almost makes me want to remove the plastic from the front of mine, leaving that zappy surface exposed.
Synaptics' knack for navigation seems to have caught. Creative tapped Synaptics for its first touch-sensitive player, the Creative Zen Touch. And Hewlett-Packard's new iPaq Pocket PC handheld has a NavPoint from Synaptics as well.

Synaptics custom designs each of its touchpads based on a client's needs. Let's take a look at the evolution of the Apple/Synaptics scroll wheel to see how those needs have changed, ultimately creating better and better iPods.

The original scroll wheel, designed by Apple, physically rotated and was not touch sensitive. I'm partial to the motionless designs that came later, but I know a couple of people who still prefer this one because they like the feeling of the control moving with their finger, as opposed to their finger rubbing a stationary scroll wheel.

After the first iPod caught on, Apple started thinking of ways to improve it. Here's where Synaptics comes into the equation. The company had already worked with Apple on its iBooks. So when Apple was looking for a way to make the iPod thinner and lighter, it elected to try out a touch-sensitive design from Synaptics. Aside from creating a more pocket-friendly iPod, the new design also prevented any potential grime from gumming up the scroll wheel's inner workings. (I've never heard of this happening, but apparently it was a concern.)

Apple considered the touch-sensitive scroll wheel an improvement over the original design but decided to migrate the playback control buttons from around the scroll wheel to above it, in a straight line. The Synaptics scroll wheel itself exposes it, while adding four touch-sensitive buttons. Initially, these buttons went over well with consumers, but some people complained that the buttons didn't always work. To me, it's a matter of design; human fingers want to know that they've pressed a button, rather than relying on visual feedback to confirm that the desired action has been accomplished.

When Apple designed the iPod Mini, those buttons had to go, because there simply wasn't enough real estate on the front of the device. The solution was a clever one. By making the scroll wheel clickable, it performs two functions: It allows for song-scrolling, and it provides playback control. To me, this was a huge design improvement because the second- and third-generation iPods' touch-sensitive playback controls didn't offer any feedback to the finger.

By making the scroll wheel clickable, it performs two functions: It allows for song-scrolling, and it provides playback control.
With the clickable scroll wheel, when you depress the wheel, you get physical feedback that lets you know that you've pushed a button. This new version worked so well that Apple decided to build it into the full-size, fourth-generation iPod, doing away with buttons altogether.

Well, there you have it--the story behind the evolution of the iPod scroll wheel. Synaptics wasn't offering its technology to any other MP3 player companies until recently, and it still doesn't offer the round version found on the iPod to anyone but Apple. However, as mentioned above, the company created a vertical version of it for Creative's Zen Touch, which evidently doesn't violate whatever agreement Synaptics has with Apple.

The Zen Touch makes a bit more sense conceptually because song lists run up and down instead of in circles. But the scroll wheel lets you scroll faster because your finger can go around continuously instead of returning to the top of the strip. To make the Zen Touch even more competitive with the iPod, I recommended to Creative that it implement a new feature that would scroll down one screen, which is the same theory behind clicking down a Web page or Word document. This might make it easier to find what you're looking for without being dizzied by all that text whizzing past you.

As for Apple's latest scroll wheel, I'm plumb out of ideas for how it could be improved. If you have some of your own, kindly let me know.