Model Prototyping — A Smart Shower Control


OXO is dedicated to make living product easy to use for everyone. Their design usually include a simple but well thought out interface and detail oriented design.

In order to design a shower control interface that align with OXO design philosophy, two design goals are

1)The interface is intuitive enough so that first time user is able to use it without any instruction including reading user’s manual.

2)The interface is usable under certain condition and constraints that often occur when having a shower, such as hands are soapy, eyes can not be opened and etc.

Design Goals

In order to achieve these two goals, I did a feature analysis. The interface should include three controls, temperature, volume and valves. Temperature and volume are continues variable, in order to make these two volume easy to be adjusted, the controls of these two variables should also be continues. As a result, I use the rotation of the control to adjust the temperature and up and down of the control to change the volume.

The valves are discontinues, so the control of valves is supposed to be discontinues as well. I use three buttons to each represent a different valve.

Feature and Use Case Analysis

Since bathroom is often steamy and hands during shower are usually wet, so I avoid using digital touch screen to control the three variables. However, there is also a digital screen on the interface to display the current temperature, and I used different color to code different temperature so if the user can not clearly see the temperature on the screen at least they can have a hind from the color.



I used a piece of white cardboard to make the main body of the shower control. Three pieces of round cardboard stick together to be thick enough as a button. I cut a line on the main body so that the button can move up and down. I used a click to connect the button and main body and the button is made so it can be rotated.


Though the user testing, the two goals are all achieved. The user was able to use the shower control without needing any instruction. In the second part of user testing, I covered the user’s eyes to see if the control is usable without seeing it, and with his eyes covered, he was successfully manipulate the shower control.

However, the test also revealed a usability issue. While the temperature and volume are controlled by one button, the user sometimes made mistakes when trying to adjust temperature and volume. It is pretty dangerous when user confused about the two adjustment especially when they want to increase the volume but actually increased the temperature.

Show your support

Clapping shows how much you appreciated Anne Zheng’s story.