Experience designer & researcher
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Control Redesign

Control Redesign


Design Brief

Controls are foundational to interaction design because they act as a conduit between the user's intention/desire and the system's ability to interpret and respond to that intent. The rise of digital controls such as touch screens has led to a decoupling of the user's intent and physical expression. What's lost in reducing a control to a simple digital button is the respect for a person's perceptual-motor skills and the sensory/sensuous ways in which we interact with the world around us. 

For this assignment, we were challenged to: redesign a control that can understand a user's context, intention, behavior, environment and physical limitations in order to create a control that is elegant, intuitive, easily learned and valuable for the user. 

Exploring Everyday Controls

I started collecting photos of controls that I interact with in my daily life. The more I looked for physical controls, the more I realized that there are controls all around us that seem invisible only because we've often grown accustomed to them--not because they work seamlessly for our needs. With many of the household appliances like a rice cooker or microwave, there are often only one or two buttons that I use while the rest have been unexplored and difficult to understand. None of the controls I took photos of provide a particularly satisfying sensory experience. 

Selecting a Target

I chose to redesign the shower control because of my own experience with struggling to adjust the two dials to get the desired water temperature. Each time I adjust the cold water dial, it's either too much or too little and I can't seem to get it just right. I thought this was a perfect example of a control that privileges how the system works rather than the user's natural way of expressing intent. The two dials mirror the system function; the water becomes cooler as you add in more cold water or vice versa. Yet the user shouldn't have to think about water temperature in terms of how the system works. In fact, we simply want the desired temperature without having to consider how to make that happen. It would be great if I could walk into the shower and it would sense my preferred temperature based on what I've been doing just prior to showering or the season. I also thought about how a shower that accurately sensed temperature could prevent water waste, which is something important to me. 

I am careful to not always design for myself so I began thinking about different contexts in which showering happens  to ground the control in a specific environment and user need. I thought about the showering experience at a public pool, gym, hospital, and even dog hair salon. Then I remembered the challenges my grandmother faces with showering. She uses a showering bench because she cannot stand for a long time and her shower has many guard rails in case she needs extra support.

Research on the Current Options 

To inform my redesign, I conducted research on how others might have solved for this challenge of controlling shower temperature for elderly or mobility challenged users. I did not find any solutions that targeted this user group. However I found many (costly) digital solutions. My critique of these designs is that while the digital solution grants a high specificity of control over the exact temperature, people don't naturally think of temperature in terms of numbers.  




Design Principles 

After guerilla research about the showering experience for elderly users or people with mobility challenges, I identified three design principles to inform the design of the shower control: 

  • The control must be placed near where the user is seated or close to his/her hand. Moving to reach the control that's traditionally placed on the same wall as the showerhead is not only inconvenient, but also dangerous as it forces the elderly person to move around. 
  • The control should be functional one-handed. Many people who use a shower while seated use the handheld attachment, which means the other hand should be free to easily adjust the temperature. 
  • The control should in a visual and tactile way indicate the status of the water temperature and flow. 

Initial Sketches 

Feedback on sketches: 

  • Feedback on my sketches revealed that while dials for temperature are often circular, temperature isn't cyclical so the circular dial doesn't match with the mental model of temperature as linear. 
  • I got questions about what material the control would be since motor skills for this user group may need more support. 
  • Some of my initial sketches were guilty of feature overload, such as adding a way to visually see how much time has passed to know water usage. I realized from the feedback that this control needed to focus on the core design issues/needs for this user group rather than trying to combine many other possibly useful features.


Based on the feedback from my initial sketches, I decided to try a control placed directly on a guard rail. Thinking about this particular placement and context helped me create some prototypes using the cylindrical structure of a guard rail. I used the length of the guard rail to indicated cold to hot temperature. This was also visually represented using color. This communicates to the user that the temperature can be changed by pushing the control up and down the rail. In my prototypes, To turn the water on and off and control the flow, the user can rotate the ring. This allows the user to keep the temperature unchanged from previous use if desired. The rotation movement of the on and off control is supported by the natural way in which someone would grab the ring. I experimented with using rubber material to simulate the experience of increased resistance as the ring is rotated toward on (to make it clear that that ring does not need to be rotated the 

Final Prototype

For the final prototype, I wanted to give a sense of how this control would be placed on a bar. Key features of the final design are:

  • Visual feedback on what the temperature is based on where the ring is placed on the color gradient. 
  • Motor/physical feedback on which direction to rotate the ring to turn on the water. 
  • Motor/physical feedback through the resistance experienced when rotating the ring, which increases as you turn the ring towards "on." This allows the user to control the flow without having to make a very specific micro-movement. 


Individual assignment for CMU Course Interaction Design Studio 2 | Spring 2017

Design thinking by exploring a problem worth solving, Ideation to simulate a preferred state, Problem framing + re-framing through low-fidelity prototyping