A Nest-Inspired Smartshower

The idea behind this prototype: how would I take the design principles behind Nest and apply it to a smart shower control?

So I made it completely touchscreen-based. No physical knobs, no moving parts. The front of the panel is a large, circular touchscreen. The side is a touch-sensitive surface acting as a multi-purpose knob. The screen shows the current time (to remind procrastinators to get out of the shower), the water temperature (also communicated via the background hue), the current water usage (also visualized by the water waves in the bottom of the screen), and the status of each water valve.

When you get in the shower, the sensor on the device detects your presence and turn on the shower automatically. When you leave, the shower turns off and remembers your temperature / water pressure preference for next time you shower. Touching the temperature indicator and swiping on the side adjusts the shower temperature; touching the one of the three valve icons and swiping adjusts the corresponding valve output independently.


My design didn’t start that way. If I were to do the project without a screen, I would have done it similar to how the single-knob shower in my apartment works — turning it initially turns on the shower, and turning it further adjusts the temperature. Its main caveat: you can’t really control how much water is coming out. But for most people, it’s good enough.

But the project requires that the user being able to control the output of multiple (3) valves. A straightforward solution would be to add 3 additional knobs for , which I thought about doing. Or having 2 knobs for temperature and water pressure, and 3 more buttons to control where the water is coming out — other students on my peer review group ended up doing that, sacrificing the ability to control output of each valve independently.

Or I can simplify. Which I did. Most people don’t really need to fiddle with the valves too much. They set it once, and leave it as that. People adjusts the temperature more often based on the weather of the day, their mood at the time, and so on. So why have multiple knobs if most of them don’t ended up being used?

And then, why have physical knobs on a digital device in a place full of water vapor? Sounds like a perfect recipe for a short-lived device.

And thus, my concept of a fully touch-based, no moving parts design was born.

An early sketch of the smart shower interface


Since the form factor of the device itself is pretty minimalist, the design of the touchscreen ended up being the focus of the prototype stage. But that’s not really the full story. Initially, I wanted to make the shape out of two cut-out disks and a circular strip. This way the prototype would be hollow, and I can cut out a slot on the side to swap the interface in and out. However, the classroom glue proved way too weak and I didn’t have superglue or anything of the sort at hand. In the end, I just stuck together three disks, and they held together to this day.

In terms of the touchscreen, the design of the shower valve icons took some careful thoughts. Drawing icons for paper prototype is always annoying because the resolution of even the finest sharpie hardly allows for the intricate details. The challenge was to draw the most simple shape that conveys the purpose of the icons. I iterated on that for some time and finally came up with my final picks.

A bunch of icons I made for the valves
All the prototype screens


I had 2 people on the same class test out the prototype, and also evaluated the prototype with my peer review group.

Feedback were positive on the inventiveness of the prototype. People were impressed by how clean and simple the shower control is, and they had no trouble understanding the interface even though few of them had been exposed to Nest products before. Although my prototype was not the only one that used color to signify shower temperature, my peer review group appreciated it nonetheless.

A student on my peer review group raised a question of the turning direction of the knob. Indeed, there’s no indication on the device itself on how turning clockwise increases the value, and different cultures may understand the meanings of directions differently. Once an user started to interact with the device, though, they would quickly realize the fact; but the device itself should also communicate it beforehand, and it’s something that I would like to improve should I carry the idea further.

Additionally, my users helped me realize that turning the shower on/off based on human presence may not be a good idea. For example, people may come into the shower room not to shower but to clean the room, and a simple proximity sensor wouldn’t be able to differentiate the cases. An improved design would be to have the shower should turn on when an user presses an “on” button on the touchscreen, and turn off when they leave.

Overall, it looks like people quite liked the idea of a Nest-like smart shower, and gave me some really valuable suggestions on the things I missed with the design. Pretty happy about that.

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