I created a touch screen shower knob that helps users personalize their bathing experience.  The screen knob replaces standard knobs and turns on whenever users step into the shower.  Users can begin their shower experience by selecting their own tile.  The shower knob stores the user’s personalization preferences, so that each time a user takes a shower they do not have to reset their preferences.  If there is a new user in the shower the shower knob also displays an “add new user” button in the form a plus sign tile.  When creating a new user for the shower, the user can select different options such as the shower or tub option, the volume of the water, the temperature of the water, and a timer for the shower.  

Intended Users

Average shower users that could have issues with dexterity and their eye sight while using the shower

The Process


I started out by writing a list of the project requirements assigned through the course. From there I begin picturing a shower and where the best place for an interface would be. While knobs are utilized in both tubs and shower, I chose to work primarily with shower functionalities, because I figured the shower would be the place where users are moving the quickest and want the most efficiency. Additionally, all of the functionalities for a shower could also be applied to users who are drawing a bath. 

I thought that the knob of the shower could be replaced with a screen, since most users are comfortable with using a shower knob and have an understanding of its functionalities, such as twisting and pulling. Additionally, I did not want the knob interface to be on throughout the day, so I thought of adding a sensitive shower mat that could detect when a user enters the bathing area.  It would have to be weight sensitive, so that the screen would not turn on if a user’s pet or child were to explore the bathing area unattended.  

In addition, I wanted the screen shower knob to be an eight sided screen, so that it could provide something to hold on to for pulling and turning purposes. With this shape in mind, I then attempted to sketch the different screens that the shower would have. I first started by addressing the project requirements.  I started adding the different screens for various options; however I shortly realized that I need to create a profile screen, so that users would not have to set their preferences each time they entered the shower, slowing their day down. Also, I thought about adding external buttons or switches to the screen’s knob. However, I realized that adding additional buttons would make it difficult for users to turn and operate the knob, so I ended up scratching the idea. 

Lastly, I reflected upon my shower experience and realized that there has recently been a push at my local gym for shower users to take shorter showers in order to save water. I thought about adding an eco-friendly aspect to my shower knob and started brainstorming different messages and designs as well as researching current images that are being utilized to urge users to save water.  I ended up sketching a timer, because I realized that messages would be difficult to read in the shower and annoying to listen to and possible display options may not be effective at communicating to the user that they should take shorter showers.  I believed that implementing a timer within the shower would seem less invasive of people’s privacy and personal time as well as allow users to utilize less water by having a timely shower. 



In order to create a model of the knob, I utilized cardboard, hot glue, and a wooden dowel.  I cut out the surface of the knob and then used the hot glue to glue strips of cardboard onto the surface of the knob in order to make the knob protrude from the cardboard that represented the wall of the bathing area.  I then added dots of glue around the outside of the strips in order to create grips that would make it easier for the user to turn and pull the knob, especially when wet.  Lastly, I cut and placed a dowel on the back of the knob. During user testing I utilized the dowel in order to simulate the turning and pulling of the knob. 

After creating the physical structure of the knob, I used paper and colored pencils in order to prototype the various screens of the knob.  I started by creating the profile screen and made each user’s icon a different color, so that each profile would easily be distinguishable. For the purposes of this prototype, I utilized the task of having a new user create a new profile.  I then made the shower or tub screen where users could select which function they wanted by choosing either the picture of the tub or the picture of the shower. Next, users would be able to select the force of the water by choosing between blast, rain, or mist.  Each of the selections were color coded like a traffic light, so users would be able to understand the amount of caution needed with each force choice.  Then, I created a temperature screen, where users could turn the knob to select the temperature, similar to current knobs.  Lastly, I made a timer, where users could select the time length of their shower. I wanted to timer to not be able to be set more than thirty minutes to avoid users knowingly taking excessive showers.  Overall, I wanted to keep the design simple, so that users would be able to quickly take a shower and select their options, even if they had removed their corrective lenses. 

Below is the video that I created in order to demonstrate the functionality and flow of the screen bathing knob. 

User Testing

I had the opportunity to have several of my classmates test out the functionality and feel off my bathing knob.  My peers mentioned that they thought the knob may be a bit too big, making it difficult for users with small hand to turn and pull out of the wall.  Each of my peers had varying hand sizes and the user with the largest hand size said that it was possible for him to turn the knob; however it was difficult, while the user with the smallest hand size mentioned that she could barely fit her hand around the knob. Addition, my peers provided me with the following feedback about the interface of the knob:   

  •  They wondered how a user would utilize the interface when the shower is running and what the interface would look like and act like when the shower is running
  • They wondered how users would add time during their shower if they needed more time
  • They wondered how a user would edit preferences and a user’s mobility during the personalization of settings
  • My peers suggested that I add an indicator on the temperature screen, so that users could understand what the temperature is

I appreciate the feedback I received from my peers immensely. I completely agree with their feedback regarding the size of the bathing knob and if I were to construct the knob all over again I would reconsider what the average hand size is of users and the size of knobs that users can grab on to.  Additionally, I would like to address the other concerns that were raised by my peers in the following bullets:

  • In order to be able to change the settings of the shower, I would probably add a screen with each of the different personalization options that would display when users were taking a shower, so that if they wanted to change a setting they would be able to select the function and view the screen associated with that function.
  •  Additionally, from this “main” screen users would be able to add more time to the timer screen by selecting the timer option.  In order to make this function easier to add time to, I would probably add a button that users could select on the timer screen that would add a five minutes to the time.  Users would be able to simply press the button and add more time, similar to the functionality of a snooze button.
  • If I were to redo the screens, I would add a back arrow and a skip button.  The back arrow would allow new users to move backwards in the interface in order to change their initial selection, while the skip button would allow users to skip certain settings. Also, I would want to add an approval screen at the end of the new user creation where users could double check their preferences and enter their name to be saved in the system with their personalization settings.
  • Lastly, I would implement my peer’s feedback and add an indicator that would display to users what temperature setting they had selected.  Additionally, I would add other indicators at the check marks already in place on my temperature screen, so that users would have a reference point to utilize when setting their personalized temperature. 



I really enjoyed working with cardboard and hot glue.  I liked being able to utilize the cardboard to create a model that was knob like. I found the cardboard easy to work with and shape into what I sketched. It was surprisingly malleable and flexible.  Additionally, I especially enjoyed being able to utilize hot glue in place of grips around the knob.  My peer group thought that my usage of hot glue was particularly clever and I enjoyed the fact that the hot glue added an extra dimension that is difficult to simulate in sketching or paper prototyping. 

Learned Lessons

During this assignment, I would say that I spent too much time working on the physical nature of the prototype and not enough time thinking about and constructing the screens of the interface.  This reflection can be attributed to the feedback I received from my peers during user testing. My peers provided me with only one piece of advice for the physical nature of the knob and several pieces of feedback regarding the screens. In addition, I learned that I should be more inclusive in my designs and take other scenarios into account.  For the purposes of this prototype I really only designed for one possible scenario, without fully thinking through other functionalities of a bathing knob or screen interfaces.  Next time I would expand my thinking to include additional tasks and scenarios in order to incorporate more of the functionalities and flow of the design.