Usability and User Experience Assessment and Product Redesign
This project focuses on optimizing the interaction and user experience of Philips HD7762 Coffee Machine through usability tests, redesigns and evaluations. Contributive methods, techniques and tools are used for simulating user-product interaction and evaluating the interaction and user experience. At the end of the project, a redesign proposal of the coffee machine with fully consideration of practical implementation is proposed and was chosen among three competitive groups to hand in to Philips Design.
As a following study to compare the process of designing interactive multi-funcational product in the future with web design framework, the paper is accepted by ACM CHI 2016 at San Jose in proceedings.
Mentor: Rene van Egmond, Jie Li
Personal Contribution: User research, Information visualization, Concept development, Rendering, Prototyping, User interface
Team: Beatrice Chichiarelli, Elske van der Ende, Niels van Hamersveld, Leonie Houwen, Jaap Meijer
02/2014 - 07/2014
Two qualitative studies, Study 1 and Study 2 were conducted in an experience lab at the faculty of Industrial Design Engineering of Delft University of Technology to simulate a daily home environment for the user tests. Study 1 was discovering user problems for redesign process. Study 2 was evaluating the redesign.
A user study was set up to find potential usability problems in the device. Seven non-designer men and women between the age of 30 and 50 participated in an approx. 30-minute user test. Each participant was asked to conduct two tasks. The first task was making three cups of strong coffee. The second task was making a cup of filter coffee while the timer was already set. If they could not perform the task at all for a while, a subtle hint was given.Using the device for the first time and fulfilling the tasks proved to be difficult for all the participants which gave a lot of insight in the usability.
User problems in Study 1 were defined into three categories, feedback, usecues and other to discover unsatisfied user needs in the current product. They were visualized in the diagram below according to the amount of participants that occurred the problem. The most prominent problems are: 1. Knob and icon of grinding size selector were not understood. 2. The relation between water scale and the cups of coffee is not clear. 3. The strength selection and filter-coffee-setting were not found or understood on digital display. The cup icon on the display refers to either number of cups or coffee strength is confused. 4. The central button was pressed repeatedly because of lacking feedback. It caused a lot of confusion by controlling too many settings. 5. The timer function was difficult to use or to set. 6. It was not clear how and when to start the brewing process. 7. Users always forgot to put in filter paper.
The three categories of problems in the number of participants for each problem
Users expect to do things in a particular sequence. It is crucial to understand the impetus of users’ actions and the process of completing tasks provided by the product. Five steps were identified to complete a coffee making process: turning on the machine, filling all necessities, personalized selections, start brewing, and waiting. The timer was considered as an additional trigger to start brewing process. The problems discovered in study 1 cause intricate interaction flows among different steps and destroy a complete sequence. Functions in each step should contain similar usecues and feedback. These require distributing components in a clear structure for each step.
In the redesign we want to give the users more appropriate feedback to make them feel more secure about what to do and how to do it, when they are making coffee. They should be more guided through the process, to make them feel more comfortable. Our design goal is:
“We want the users to feel guided and secure when using the coffee machine.”
We want the qualities of the interaction to be easy, friendly and natural. The operation of the machine should be natural and clear. The user should be guided very natural through the process of coffee making in a friendly way. The user should experience the use and the interaction as relaxed and controlled. They should feel confident and have the idea that they can control the coffee making, in a relaxed way.
Following the structured user flow, divisions of the physical interface were redefined. User is able to turn on the machine by touching any button as step 1. On top, transparent bean containers and water reservoir imply filling the ingredients first. An evident sign is added to the filter part to remind user of putting filter paper. The selection knob of bean container and grinding size are placed on top of the bean container because of mechanical reason. Coffee strength is controlled by the central selection button, which is replaced by a knob with pointer to result in a same design language with bean selector and grinding size selector. All three knobs belong to the second division of physical interface. The timer setting as an individual unit, which is not used every time, is separated from normal selections. As user goes down to the bottom, they can press start-brewing button to start making coffee. This prevents users start the brewing process by mistake before finishing former steps. Each time when the user activates the machine, the interface settings remember the last settings that were made. This smart default solution is based on the fact that people tend to stick to a comfortable choice for daily household product for some time.
The on/off button
This button is removed from the device. By pressing any button the machine will turn on and after 5 minutes of inactivity, the machine will turn off automatically. Holding on the start button for 3 seconds can also be used to turn off the device manually.
Bean reservoir selection button
This rotating knob (1) will have exactly the same functionality, but will now have the appearance of a cylinder with an out sticking pointer that points to one of the three icons that illustrates the selection of bean reservoir(s). This asymmetric shape will make sure there will not be any confusion about reservoir selection. The knob will still have three possible positions.
The new lid is made of see through material that suggests the location of the water reservoir (3). The water scale is now placed on the right side of the lid as oppose to being hidden below the lid. Because of these two alterations, the water reservoir can always be seen from top and the user can constantly see the amount of water that is currently in the machine because of the scale.
The ring of buttons around the knob is removed, its functions are made to be obsolete or adjusted elsewhere. The knob itself now has the shape of a cylinder with a pointer attached to it (4). It can only shift among four different positions, always pointing towards one of the four settings on the right side of the knob. On top of the knob a rotating ring is attached that can be used for time settings. Just like the old button the front side of the knob is a pressing button, which now can be used to confirm time settings. Another important addition is a circular light around the central button, that serves as a progress bar.
Placed around the right side of the central button are four icons with light (5). Three of the icons are visualizations of beans showing one, two and three beans that indicate the strength of the coffee from low to high respectively. The fourth icon is the depiction of a coffee spoon, for the user who wants to make coffee from coffee powder. These make a total of four different selectable icons. When the machine is turned on, three of these icons will be lit up slightly to be visible and the icon that is selected by the pointer will be brightly lit up. When the coffee making process starts, only the selected icon will be visible and the circular progress circle will begin to appear from the selected icon.
The old time button is divided into two new buttons that can set up the clock and timer separately (6). When you press the timer icon, the outline of the button will light up and the set time will appear underneath the clock to indicate that it is set. If you press it again, the timer will be turned off. Holding the timer button for 2 seconds will open the timer menu. The hour of the timer starts to blink and the ring on the central button will be light up with ridges, which can be used to change the amount of hours and minutes. By clicking the central button, the timer is confirmed. When the timer icon is selected or a timer is set the light of the start button will turn off so the user knows it is impossible to start the device manually at those moments.
At the bottom of the device a new button is placed which has the function of starting the coffee making process (7). The button will be lit up as soon as the device turns on and can be pressed immediately to start coffee making. At this point the light of the button will start flickering in a slow tempo to suggest the machine is in the process of grinding or brewing.
Water sensor The user will no longer need to select the amount of cups to make sure the corresponding amount of beans will be grinded. In the redesign a sensor will be added inside the water reservoir, which measures the amount of water. This information will then be used by the machine to grind as much beans as needed according to the amount of water that the user put in the water reservoir.
When the machine is off, only clock and timer display are lit up. After turning on the machine, all icons are lit up. Coffee types that are not selected are less bright (1). Holding the alarm icon for two seconds, an outline lights up with the alarm setting menu. The hours start blinking and the turning ring around the central knob lights up to suggest users using the ring for timer adjustment. Pressing central button to confirm the hours. The same goes for setting the clock. When the alarm is set, the set time and an alarm-icon appears (2).
When the start button is pressed to initiate brewing process, all icons disappear except for the chosen coffee type. A circular light around the central button appears as progress bar to communicate how long it takes before the coffee is ready see Figure 7 (3). The light of start-brewing button starts flickering in a slow tempo to suggest the process of grinding and brewing. It stops when the coffee is ready (4). As soon as the machine is on, the start-brewing button is lit up for users who prefer to use presets. If timer is already set, the light of start-brewing button will be off unless the user cancels the timer.
As an evaluation of the redesign, an interactive prototype to largely simulate the experience was created to perform Study 2. The same user tasks were conducted as in Study 1. All participants knew immediately where to put water and beans as their first actions. All of them filled the machine with right amount of water, apart from one participant not knowing this decided the cups. Participants mostly followed the redesigned user flow from top to bottom. No one started brewing accidently as frequent mistakes appeared in Study 1. With regard to the central button, their first intention was turning to set up the strength. Users were all able to find out the timer function and change the time because of clear separation from the strength selector. Accurate use of light usecues and feedback clearly differentiate five steps and improve the usability. Since the coarseness button is not the priority and was placed on the top of the machine, some participant didn’t notice it. Overall users in Study 2 felt much more guided and secure than users in Study 1.