Handheld Devices and the Flow of Functionality

Handheld devices and small appliances pose a unique challenge to the interface designer. The blur between user interface and functionality (interface vs. interaction) is even more pronounced in these environments. The interface of any small device is extremely important; yet, more than ever, the necessity to build in exactly (and only) what is required by the user is extremely important!

Part of the interface designer’s job has to be to define what is needed. Breaking the tasks down into meaningful chunks is as much a part of the interface as anything you see. The flow of functionality is critical to the usability of the device. Style is important, but style is drastically different than design. (See http://www.alistapart.com/stories/bathingape/ .)

Mihalyi Csikszentmihalyi coined the term “Flow” to describe that state when you are lost in the doing of something, with no awareness of outside time. (See Flow : The Psychology of Optimal Experience). I like to extend this into my definition of a well designed piece of software: the user enters a state of flow as it relates to their job and is unaware of the computer as being a barrier getting in the way of accomplishing a task. The user should not be conscious of the tool anymore than a carpenter has to think about using a saw. Instead, the carpenter thinks about cutting a piece of wood.

What’s Wrong Now?

On a handheld device, the need to concentrate on the device in order to accomplish a task has made adoption a bit slow, to say the least. Clumsy interfaces, ill-conceived tasks, ”noisy” screens (too many fonts and now, too many colors!), and total dependence on a stylus. One-handed operation, for example, would eliminate a stylus. These are a few of the things that can interrupt the flow of functionality.

Rather than concentrating on completing a task, the users are thinking “Okay, now I have to touch the stylus HERE and then drag it over THERE. Oops. I let go in the wrong place. So now I need to put it back over THERE and start over.” If this is the thought process of the user, quick: tell me what task they are trying to accomplish! Give up? That’s because the user isn’t even close to thinking about the task but is expending all their efforts on using the device.

Single Mindedness of  Purpose

While some handheld devices continue to expand into trying to be all things to all people (after all, how many devices do you really want to carry around?), appliances need to do one thing well. They are highly customized for their use and the interface/interaction needs to be extremely well focused and well-thought out tasks. I’m not going to enter the argument about where interface and interaction collide and overlap. I’m much more interested in designing good applications than arguing terms. Important points are:

• Appliances and handheld devices typically need to do one thing really well
• Single minded purposes means the consistency of the interface is very important
• Where guidelines exist for various platforms, make use of standards so that the application already looks familiar

Environmental Differences

Other differences that set appliances and handheld devices apart from typical software applications include:

• Small screen size: real estate is extremely limited
• Different means of input (tiny keyboards, no keyboard, stylus, fingers, infrared, radio)
• The fact that these devices are used all over the place—not just at a desk in an office, but in the kitchen, in the car, while walking, while doing some other job, and so forth

User Differences

Because appliances and handheld devices are generally aimed at a consumer market rather than a technical one, applications need to be designed so that they are extremely intuitive to use for several reasons:

• The user is typically less technically familiar
• The user does not want to spend time learning how to use something
• The user is typically multi-tasking while using a device; the device is just one point of focus
• The user is not likely to flip through a piece of documentation to look up something;  how things work needs to be very obvious

Summary

In summary, the focus when defining the needs and designing the interface of an appliance or handheld device needs to be:

• Appropriate functionality
• Consistency within the platform, if possible
• Consistency within the application
• Intuitive flow of function