UX Design for
Numi 2 Intelligent toilet

Project Detail

Type: UX Design

Year: 2017 to 2019

Product: a smart home toilet with advanced toilet and bidet features. It is controlled by smart home app, wireless remote, and built-in voice assistant (Amazon Alexa). It has animated lighting and ambient sound.

Background

  • Numi 1 was launched in 2008 and in need of upgrade with modern technology.

  • Kohler Konnect App v1.0 was just released and Kohler wants to push to launch more smart home products.

Here is a quick comparison of product specs scoped by the project team:

Numi 1

  • Touch Remote

  • Color lighting

  • Ambient sound, radio, bluetooth speaker

Numi 2

  • App & Voice Assistant

  • Theme lighting

  • Ambient music, streaming music, bluetooth speaker

Responsibility

I am responsible for the UX design and design management including:

  1. Conduct research and facilitate workshops about smart bathroom experience.

  2. Define UX strategy including ambient experience and control experience.

  3. Design ambient lighting and sound (with NOK Creatives).

  4. Managing smart home app design (with Isar Design).

  5. Design remote and voice control experience.

Define Numi 2 UX Strategy

There are two main challenges. First, how does Numi 2 improve bathroom experience by having atmospheric lighting and sound? It should be meaningful to users rather than purely aesthetic.

Secondly, how can we reduce the complexity of having a multitude of features and different control options. Our previous research suggested that smart home devices often require too many interactions and user attentions for simple tasks.

Thus, the focus of Numi 2 user experience are divided in two parts: ambient experience and toileting experience.

The Numi 2 UX strategy is to focus on toilet and ambient experience.

Ambient Experience

Start from user journey

In the exploratory workshop, we used experience map to investigate users’ behaviors in the bathroom. There were three scenarios that caught our attentions: morning routine, midnight wakeup, and isolation.

Morning routine are people’s activities including toileting, oral hygiene, grooming, and makeup after waking up. The bathroom is the quintessential place for them to boost the mood and prepare for the day.

Midnight wakeup is the scenario when people wake up to use the toilet. They are drowsy and might not remember to flush the toilet. Moreover, their sleepiness might be disrupted by the bathroom light.

Isolation is the escapist moment people want to be alone to fantasize, let up, or indulge without distraction.

To provide atmospheric lighting and sound to support users’ activities and mood, there are three directions proposed for Numi 2 ambient experience.

1) Circadian Lighting

2) Entertainment Lighting

3) Control Feedback Lighting

The green problem

Tens of animation clips were tested for one circadian lighting theme.

Prototyping and Testing

When the first prototype was built, I quickly found out few problems. The light is not diffused well and the colors didn’t look good. Most importantly, it’s hard to identify the cause of bad lighting effect—whether the animation the design agency created or the prototype itself.

I proposed three testing to the team to identify the problems.

  1. Testing color performance.

  2. Benchmarking other smart lighting product design.

  3. Developing software tools for designers to use to check on the result directly.

This test helped designers to understand how color rendered on the lighting panel.

Benchmarking other products to build a better prototype.

Acquiring software tool so designer can export to the prototype to inspect the result directly.

Final Design

Nature Themes—Sunrise, Forest Breeze, and Deep Ocean are designed with natural images and sound to provide an assuring and friendly environment in the bathroom. These aim to help users relaxed and more easily focus throughout the day.

Entertainment themes—Bokeh and Miami are designed to boost the moods whenever people feel needed, in the shower, bathing, or preparing for a night out. The lighting effect in Bokeh and Miami will also respond to the music played by the user via bluetooth connection.

  • Sunrise

  • Forest Breeze

  • Deep Ocean

  • Bokeh

  • Miami

Demo of all lighting theme.

Based on these five lighting themes, I discussed with the music composers to create the sound and music for each theme. Here is one demo of Bokeh theme.

Circadian rhythm is another detail of the ambient experience. It aims to change lighting and sound throughout the day based on circadian clock to improve our wellness. For instance in Sunrise theme, there are sounds of wind blowing through the tall grass during the daytime and sounds of crickets chirping during the nighttime. The brightness and hue of the lighting will change accordingly too.

Toilet Experience

As mentioned in UX strategy, it is important to bring different functions into relevant scenarios without causing confusion. I ranked control methods of automation, remote, voice assistant, and smartphone application based on 3 factors: the easiness of learning, the complexity of required actions, the responsiveness of feedbacks.

The second step was to create feature map and assign them to each control methods.

Automatic Control

This controls the basic but convenient features such as lid opening and auto flushing. There are feedback lighting to notify users the toilet is operating.

When the lid opens.

When the music unmutes.

Remote

Numi 2 remote is greatly simplified to 9 buttons comparing to the old full-functional touch remote.

Voice Assistant

Focuses on providing toilet function adjustment, start and stop scenes, and general requests. For China version, we customized 20 natural language comments and for global version, we followed Amazon Alexa skills. I also created lighting feedback during voice commands by following AVS Attention System.

Listening

voice assistant thinking

Thinking

voice assistant talking

Talking

Mobile App

Provides detail settings of personalized preferences and cross-products-smart-home scenes for better experience in the bathroom space.

Mobile App UX Design

The key to improving the Numi 2 app design is to prioritize features and employ different interactions to enhance usability. For main features such as front wash and dryer, a dialing-wheel design allows users to adjust water temperature and pressure easily. Secondary features such as sanitization and seat/cover control utilize a mobile-friendly design with switches and pop-up menus. Customizable features such as auto-flush and night light settings are placed in the settings page to minimize cognitive load.

Lighting is the standout feature of the entire product. To reflect its significance, the lighting control page places the animation at the center of the design, making it the focal point. This design choice allows users to quickly associate the app with the product and receive real-time feedback about their actions.

Learnings

This was the hero project for my time working in Kohler. The product was complicated and there were many parties involved to deliver design and implement features. To manage the every aspect of user experience in this project, my main learnings are:

  1. Understanding how everything works, for instance, the communications among voice control module, lighting control module, and toilet function module, helps a great deal to deliver satisfying yet realistic UX design on different control methods.

  2. It is important to have solid use cases, since they will be instrumental in creating UX strategy and design stories for further use.

  3. Iterating design and prototyping fast and frequently will not only improve digital UX design but also physical product UX design.

 Accolades

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