Model Prototyping

I created three model prototypes for shower control systems. The goal was to create a physical and digital control system in the style of the OXO brand.

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For this project, I had the option of creating an immersion blender, a stud finder, or a shower controller. I focused on creating a shower control system, partly because I think it provides some unique design constraints related to use in soapy water, but also because it is so frequently used. Immersion blenders and stud finders are no doubt practical tools, but they are not typically used on a daily basis. I’m also less familiar with how both work.


The design brief came with some set constraints. The product had to have a volume equivalent of 4 x 4 x 2 inches. The weight was suggested to be approximately 0.75 pounds. It had to be wall mounted. It had to have a digital display with settings for temperature, volume, and valve control. Additionally, it had to be easy to use when visibility and dexterity were compromised. I found this last constraint to be especially compelling. As the assignment was designed to practice prototyping physical objects, I felt that designing an object that could be used with soapy hands and eyes closed to be a quality design challenge.


I sought to create three different control schemes that, once learned, could be manipulated easily and precisely with one’s eyes closed. My assumption was that the most used controls would be for adjusting temperature and flow. In an effort to simplify the design as much as possible, I omitted any On/Off switch and included this functionality into the flow controller. For my final design I settled on a joystick model that would use the X and Y, a set of horizontal sliders, and a large dial that, when depressed, would toggle between flow and temperature controls.


There are many benefits to a well-designed physical device: actions are memorable, precisely modified without visual feedback, and satisfying. I sought to combine these with digital luxuries not currently provided in shower control systems: user presets, curved adjustment of temperature, a digital screen for info about time and weather, a digital thermometer, and a flow rate monitor. Since this assignment was focused on building a physical prototype, I my energy was on testing form and ergonomics, and how these interact with the control schema, as opposed to the digital interface itself. As a result, the digital UI is represented via low fidelity sticky notes. Instead of going in depth into user presets and, these sticky notes just list temperature and time. With that being said, all designs incorporate a digital display and could easily handle these additional features.


The joystick was designed to control temperature on the X axis and flow on the Y axis. In an effort to make it easily accessible, the off action is placed in the center of the device. This creates another advantage in that both cold and hot can be quickly accessed when turning the shower on. The box shaped controller is designed to be placed lower on the wall so that you can see the top and front of the box easily. The top of the box includes a digital display that can be glanced at to get relevant information such as flow rate and current temperature.

Joystick Sketch


The slider is similar to the joystick model except that the X and Y axises have been broken and both placed along the X axis. The goal further simplify the control by employing the left-to-right, less-to-more analogy. Although I believe this design was successful in that regard, since the two sliders are identical it could be difficult to distinguish between them with soapy, closed eyes.

Sliders Sketch


This design is very similar to the Nest thermostat system applied to shower control. I sought to make a knob that incorporated two actions, twisting and pushing. The twisting would utilize a digital indicator to mark position, and the pushing would be used to toggle modes and turn the shower on and off. I felt the knob was the most compelling idea because of its simplicity and power. The final prototype had a surprisingly pleasing feeling when you pushed it.

Know Sketch


The joystick was built with matboard, a rubber band to allow the joystick to move, and an Allen wrench with a wooden button glued to the top. The slider prototype used a foam core with pins to simulate the sliders.

Photos - Joystick & Slider

The knob was built with laser cut mat board that was etched to allow it to bend in a circle. An alligator clip was used at the bottom to give a springy feeling when you pushed down on the nob, and several pieces of wood and crumpled tin foil were added to give the product more weight. I used colored construction paper and interchangeable sticky notes to create the interface.

Knob Sketch Photos - Knob

User Test & Reflections

The user test was very simple. I tested the knob with one individual and gave them task-based instructions but no detailed walk through. The task list was to set the water temperature, turn the water on, turn the temperature up, turn the temperature down, switch to the tub, and turn the water off. The participant completed all the tasks easily with minimal guidance. The only thing I did not expect, was the participant did the press-and-hold action for less time than expected.

After the test, the participant said they liked how the knob felt and enjoyed the button press action. They said they would be excited to try it out and looked forward to it being sturdy enough to “whack strongly” to turn on and off. The participant also mentioned that they were distracted by the UI and the fact that it was not constantly changing. This was an oversight on my part, as I made sticky notes to represent some screens but not others.

For future testing, I think it would be better to either make all or none of the screens change. The participant also remarked that the physical placement of the indicator arrow was distracting tot them. This was designed to be a digital component, but I created a physical representation of it on the prototype.