The Ever-Evolving Appliance User Interface
Interface design, button design and increasing connectivity options allow for an easier end-user experience, and help eliminate the need to change product design based on different regions.
For anyone who designs user interfaces, if you see a typical television set from the mid 50s, the first thing that’s likely to catch your attention is just how much real estate was occupied by its user interface. There were two large knobs, one for volume control and the other for channel selection, along with a large area of what looked like unused space below the small screen that housed the mono speaker. This was nothing less than state of the art in its day.
Today, there are products that allow manufacturers to have simulated surround sound and high-quality video in the palm of a hand. One of the best areas to see this change is in the new appliance products produced in today’s marketplace. This article will take a look at the available options for selecting the best appliance user-interface technology; guidelines for how to decide between different types of user-interface buttons; and the use of touch screens and graphics.
Today’s appliances are a balance of form and function. The demand from users to include complex cooking, cooling or even reheating algorithms might help sell a product, but these features will always be trumped by “love at first sight,” based on how the product looks and how the user interacts with it. Simple, clean and powerful are the guidelines that product designers use today.
Think of the television of yesteryear and how simple that interface was: a knob for tuning and one for volume. Compare that to a microwave of just a couple of years ago, and you will see that there are buttons for making popcorn, melting butter or even reheating pizza. Some recent microwaves added buttons that bring up submenus driven by the hard-to-read alphanumeric displays, which tend to lead to confusion on what results you might get.
The common trend with buttons is to use universal symbols on them, so that the products can be sold in many different locations without the need to produce different buttons with different languages or localization. For example, at the 2011 Consumer Electronic Show (CES), a visitor did not see many buttons on the washers and dryers being displayed, nor labels like “start” and “stop.” However, many had single buttons with the symbol for “play” and “pause” on it. Another button that is being seen more frequently is the symbol for “power.”
These symbols have become synonymous with the electronic products produced today, and they are finding their way outside this market to all consumer products, as more electronics are designed into the products we buy.
There is, however, one other thing that using symbols in place of words cannot do for the user interface, and that is to make the buttons soft buttons. A “soft” button makes use of the display on the product to label the button’s functionality. Therefore, the button can have many different functions-or the same functions but displayed in a different language-reducing the need to produce products for different areas.
The concept of soft buttons also helps to make the user interface crisp. For example, think of a side-by-side refrigerator with an ice/water dispenser built into the front of it. Not so long ago, it would have had a mechanical button for crushed ice, one for cubes and one for the light in the ice/water dispenser area. In this case, inside each door is a rotating knob that sets the temperature of the freezer and refrigerator sides of the unit, respectively. Such refrigerators do not have any feedback as to the current temperatures inside the unit, nor the ability to customize how the lighting looked on the inside of the unit. There is a circuit board for each of the button/knob locations, and labels on or around each of these printed in a given language.
Today, we can take that same design and move the entire interface to just above the ice/water-dispenser area on the outside of the refrigerator-a user interface that consists of no more than two fixed buttons and a graphical display. Users can see what the temperatures are in both the freezer and refrigerator, change them if desired, check the status of the water filter and more-without opening the door.
Two questions that come up from time to time are how much information is too much, and what is the best way to display the information? If all of the information possible were displayed at the same time, then the details would be lost to the user. The goal with today’s user interfaces is to provide the high-level information that most users will likely want to see most often, along with intuitive drill-down menus that will quickly get the user the additional information that they desire. The manufacturer must also provide a clean and easy way back the home screen.
For example, a water-filter soft button might show green if it is OK and has about 30% life. It could then change to yellow or even red when its life falls below 30%. In this case, the user is given a simple visual status of the filter. However, if they see green and want to know just what the life of the filter may be, all they have to do is touch the button and the display will show more detailed information about it.
There are also some underlying reasons that a designer might want to use display technology with one or two simple buttons, over fixed displays or several buttons. The foremost reason is that, as time goes on, the information can be upgraded or changed as needed. Today’s embedded microcontrollers, which drive much of the technology talked about in this article, have provisions for connectivity.
Manufacturers can utilize this connectivity to update the firmware in the product. This could be as simple as providing the end user with a USB port that allows them to download updates from the manufacturers’ Web site, or it might use connected wired or wireless paths and automatically send the updates to the appliance.
For example, washing-machine manufacturers spend countless hours developing how to keep the little balls of lint from building up on clothes when washed. Imagine that just after a consumer bought a new washer and dryer there was a discovery of a new algorithm that prevented this lint buildup. Ideally, this wouldn’t be an issue, as the manufacturer would send an email to all owners explaining how to push a few buttons on the washer and dryer to receive the updated software. Because of the new program, the consumer could also receive an updated display menu, which could not have been done if the machine was made with an older, fixed display.
There are several different technologies that can be used for either the display or outside buttons. First, the displays that are in use today are getting larger and have higher resolutions (or pixels per inch). In the past, resistive touch screens were used over the display, but their typical polyester film surfaces were prone to scratches and had lower levels of light, making the displays look dull.
Newer technology is making use of projected-capacitive sensors that are sputtered on the back of the glass and mounted in front of the display. The technology that is used to manufacture projected-capacitive sensors allows for greater light transmission, which in turns allows the display to appear brighter. Projected-capacitive technology also allows for multi-touch inputs on the display, if needed.
As for the buttons outside of the display, there are several technologies that can be used. There are standard capacitive-touch buttons that have some covering plate over them that is not conductive, such as glass or plastic. These types of buttons can be found on almost every type of product.
With capacitive buttons, one does not have to apply force to depress them, but physical contact must be made to change the capacitance and register a touch-so there are some tradeoffs. First, gloves or the end of a wooden spoon will not activate them, so using them on the backsplash of a stove, for example, can be tricky.
Second, there are people who want tactile feedback from their buttons. To solve this issue, many designers have either stayed with mechanical buttons or used metal over cap technology. Metal over cap measures the deflection of the front service panel through a capacitive sensor and a target mounted above it. This allows the user to use a gloved hand or the end of a wooden spoon to activate a button. The one thing that people always notice about this type of technology is the fact that it does take a bit of force on the button, which is unlike standard capacitive-touch technology.
Where is the future of user interfaces going within the appliance market? Smart energy and the smart grid projects will definitely have an impact on what information will be displayed and where it will be displayed on appliances.
Standards are being developed that will allow for the interoperation of appliances. This will not just allow a refrigerator and oven to talk to each other and the meter base at a house, but also to a thermostat, hot water heater, washer and dryer, and other appliances.
There are locations around the world that now have tiered prices for power, based on average use and demand. Therefore, using the dishwasher right after dinner might not be the most cost-effective time. It would be nice if, after dinner, when a consumer goes to start the dishwasher, that its display would provide feedback comparing the cost of running it right away versus four hours later. This real-time information would allow consumers to make the best choices for their situation.
The state of user interfaces is ever evolving to provide users with more information and cleaner designs, along with the ability to customize the information displayed to their needs. All of this allows for more consistent manufacturing processes and eliminates the need to produce products for specific regions. Additionally, the same microcontrollers used in these displays can provide connectivity. Such integration can enable manufacturers to diagnose and upgrade products without having to visit the homeowner; saving both the manufacturer and the homeowner time and money.