Come Back Dials—All Is Forgiven22 Sep 2008
Although digital devices have many benefits over their analogue predecessors, their one main drawback is their lack of dials as input devices. Dials are a natural, easy to use way to select values in discrete or continuous ranges. Selecting values with a dial is easier than typing values with a keyboard or repeatedly pressing buttons that increment or decrement values. Dials give one a sense of the size of the change: turning the dial by a larger amount increases or decreases the value by a larger amount; turning the dial by a smaller amount increases or decreases the value by a smaller amount. Repeatedly pressing increment or decrement buttons just doesn’t feel the same.
Device designers favor buttons over dials because buttons are easier and cheaper to add to products because they occupy less space on the circuit board and on the front control panel. And, to be fair, buttons are more efficient for entering numeric sequences. For example, dialling a phone number is faster with a push button numeric keypad than waiting for the dial to return to its home position before entering the next number. However, dials won’t go away; they are embedded in our culture: we still refer to entering a phone number as dialing, even though many people nowadays have never used a phone with a dial.
As device designers rediscover the user interface benefits of dials—like anthropologists rediscovering the wisdom of the ancients—dials are making a comeback. The scroll wheel on a mouse is a vertical dial. Logitech’s NuLOOQ navigator is a horizontal dial. Both the scroll wheel and the NuLOOQ enhance dials with push-button functionality illustrating that dials can—and should—evolve to meet the demands of new applications.
One device that successfully uses dials is the digital SLR camera. Typical D-SLRs have dials for selecting the shooting mode—automatic, aperture priority, shutter priority, etc.—for selecting the ISO sensitivity and the exposure compensation, and for selecting auto-focus points. Some of the dials on a D-SLRs camera replicate the dials on their 35mm-film counterparts; other dials are new input devices for selecting items listed on the D-SLR’s LCD monitor. Both types of dial are easy to use and have that subjective, unquantifiable quality—they just feel right.
Not all attempts at re-incorporating dials into user interfaces have been successful. The biggest failures have been the dials reproduced as graphical widgets by user-interface toolkits. On-screen dials are difficult to use because they force users to drag the mouse in a circular motion, often in small increments. PCs already have a range of input devices—keyboards, mice, joysticks and touch pads—why not add a dial to the side of the keyboard? One hand would move the mouse, the other hand would turn the dial. Such a dial would make scrolling long documents faster and easier and reduce strain on mousing hands and fingers that spend long periods scratching the mouse between the first and second buttons. A scroll dial on the keyboard would also enable easier navigation of pan-and-zoom user interfaces: one hand would move the cursor across the plane and select data, the other hand would zoom in and out of the plane.