Wynd Sentry

Sentry is the world's first non-intrusive device that protects rental properties by reliably detecting recreational smoke and unwanted noise.

In this project, I led the design of Sentry Mobile App across iOS, Android, Tables, Desktop and Web since the outset of the project in May 2022. Up until now, I led efforts to evolve the service and address customer pain‐points related to the user experience.

Disclaimer: To comply with my non-disclosure agreement, I have omitted and obfuscated confidential information in this case study. All information in this case study is my own and does not necessarily reflect the views of Wynd Technologies, Inc.


May 2022- Now

Team Structure

2 Product Managers
5 Software Engineers


Leading the end-to-end design of Sentry app experiences

Customer Insights & Ideation

I collaborated closely with 2 product managers to uncover valuable insights and translate conceptual ideas into features that meet customer needs and address their pain points.

Experience Strategy & Vision

I developed frameworks and prototypes to communicate the vision, design principles, and content strategy, which are important to promote ideas, achieve consensus, and facilitate the decision-making process.

Planning & Scope Definition

I drive the product direction with my project manager partners. I advocated for customer-centricity and balanced it with the needs of the business. I prioritized and negotiated features for launch and future iterations.

Oversight & Coordination

I collaborated with 5 software engineers to ensure the successful implementation.

Design Execution & Validation

I executed journeys, usability testing, wireframes, prototypes and design specs.


I presented works to gain buy‐in from executives, stakeholders, and investors throughout the project lifecycle.

The contexts

Exploring the solution for managing smoking and noise incidents

Smoking poses significant challenges and drawbacks to short-term rental properties owners. Finding effective strategies and implementing stringent measures to prevent and address smoking incidents will help create smoke-free environments that enhance guest satisfaction, uphold property standards, and ultimately improve the overall guest experience.

Wynd is planning to launch Sentry, the first non-intrusive device that monitors the indoor P.M. level and dB level to prevent, mitigate, and deter smoking and noise incidents for short-term rental properties owners.


Despite the loss caused by indoor smoking or noisy parties, there’s no solution provided to rental property owners to discourage or reduce such incidents in their units or recover their loss.


Property Owners: 
Have no way of knowing what’s going on with their properties.

Lack of transparency

When a smoking or noise incident happens, property owners are unable to know and respond to it in the first place.

Complaints & negative reviews

Despite having strict policies, customers frequently receives complaints from guests or neighbors about the smell of smoking or loud noise in the unit.

Guest denial

Guests usually deny those incidents in most of cases.

Large financial loss

The average smoking damage claim costs property owners $1,600 per incident, including Ozone machine, cleaning fee, and room vacancy fee.

Property management systems: 
Choose to support guests when there’s no proofs.

Property management platforms like Airbnb or VRBO couldn’t verify the proof provided by property owners, so they tend to stand with guests for the long term profits.

Insurance providers: 
Couldn’t process the claim due to the insufficient info provided by property owners.

After an incident happens and causes loss, property owners couldn’t submit sufficient data to the insurance providers to recover the loss so insurance providers usually are unable to process the claim.

design question

How might we build a mobile app from scratch paired with the hardware device that brings transparency to property owners and helps them recover the loss after smoking and noise incidents happen?


A comprehensive device to actively monitor noise level and smoking level in the properties.

Hardware device: actively detect smoking & noise levels in the environment.

Mobile App: allow users to manage devices and view information in their rental properties.

the competitors

There’s no competitors who can cover both smoking and noise incident at the time.

user flow & user journey Map

Organize all the scenarios and design opportunities.

I created the user journey map and user flow to provide a comprehensive overview of all use cases and scenarios within the app. By mapping out the different paths and interactions that users may encounter, we gain a holistic understanding of the app's functionality, how users navigate through it, what’s the potential edge cases, and pinpoint any potential opportunity areas.

concept testing

Concept testing

I conducted concept testing with 4 target users to validate the design idea, workflow, desired features of the app.

information architecture

Overall information architecture of the app

I constructed this information architecture to outline all app pages, features, decision points, and specific functionalities. This ensures a structured and intuitive framework for a seamless user experience.


Visualize and iterate my design from vague to clear, rough to concrete.

I constructed prototypes with different levels fidelities to visualize and gradually narrow done the feature, details, and design language.

usability testing & insights

Usability testing

I conducted usability testing with 5 target users to validate the design decisions, evaluate usability of the design, and explore potential future updates to the design.


Instead of just seeing overview, users want to know the live status of their property
I recommended to live data to each property and device (live smoke level, noise level, etc). Showing more information to users about the live status of their property.
Since we are using many terms of air quality, many users are having some difficulties to adapt to them.
I recommended to add more instructions, like what different levels of P.M. and dB mean, what different settings mean.
When incident happens, users want to have a short cut to check with their guests and find out what’s going on. Ideally, they want to automate this process for efficiency.
I recommended to allow users to send messages to their guests to check incidents directly from our app. Also, users can connect their properties on the app with other property management platforms like AirBnb and automatically send out the messages to their guests if incidents happen.
Users value smoke incidents more than noise incidents. In addition to smoke incidents, they want to know what’s the source causing the incident.
I recommended to add the type of smoking incidents, including cigarette, marijuana, cigar, and vape.

engineer mid-check meeting

Prioritize our findings

Due to constraints in time and resource, I had a meeting with engineers to communicate and prioritize each findings I found in the usability testing in terms of development schedule.

In the meeting, we listed out all the potential features we can have and sort them by MVP, Will do, and Won’t do based on product requirements, priority, available resources, and constraints.

rounds after rounds iterations

Crazily iterating on the design...

You know...what I'm showing here is just the iceberg of the iterations...

Highlighted features

Simple onboarding

Sentry app allows users to easily pair up the devices and setup the notification preference step by step.

Live - monitoring

Sentry app features real-time device data to provide continuous monitoring of indoor air quality and noise levels, helping users maintain a healthy indoor environment for their guests.

Incident alerts

Sentry alerts users in real-time whenever someone is smoking including cigarette, marijuana, and cigar smoke or when noise is above the threshold and lasts more than the duration set by users

Incident details & settings

Users can view incident details and information, including the incident types, incident probability, start time and duration of the incident, and incident line graph. The activity logs provide users a more detailed timeline about the incident. Users can choose to use the crafted messages to contact guests if they want to do so. Also, users can change the room info of the device and change the sensitivity of the incident detection on the device settings page.

Tamper protection & alerts

Users will receive alerts when the device is unplugged or disconnected from the internet, allowing them to take appropriate action.

Evidence-based incident report

Incident reports are designed to help users recover the loss caused by smoking or noise incidents from either property management systems or insurance providers. Whenever Sentry detects an incident such as recreational smoke or excessive noise, it records the time and duration of the event and generates an incident report.

Design system

Constructing an sustainable design system for Wynd's mobile product

I built the design system from scratch. The design system is not only for Wynd Sentry mobile app, but also scalable to other mobile apps Wynd plans to do in the future.

(Note: Due to NDA, I'm only allowed to show partial design system here.)


Design is never the end of the process

To ensure a successful launch of the app, I need to best guide the handoff process from transitioning my design to the implemented version. I also need to facilitate the engineers to check the implemented version once they finish their tickets

Handoff preparation

I construct design systems for the team (e.g. typography, theme colors, button sizes, etc.) and specify all UI guidelines (margin, spacing, etc). I demonstrate the entire flow and consider all the use cases in static and interactive format. I also attach additional resources needed for development (e.g. images, logos, etc.).

Handoff meeting

I hold a meeting to officially handoff my work to the engineers for the implementation. I use an interactive prototype to show them the entire flow. Also I present a document detailing where they could find each material.

QA testing

After engineers finish each ticket they are assigned to, they would notify me to conduct QA testing to ensure every detail is right.

The results

A great start…But this is not at the end

$600k + ARR
since launched

After launching Sentry device & Mobile apps, we increased more than $600k ARR (Annual Recurring Revenue).

800 units sold
in Q1

For the first quarter after we launch and ship Sentry units, we sold 800 units on the E-commerce side.

3 Awards

After launched, Sentry received 3 international awards: DNA Paris Design Awards Winner, CES Innovation Awards Honoree, and London Design Awards Gold.

Quotes from our customers and clients:


AT LONG LAST! I finally found something that ca ndetect cigarette smoke accurately for my rental property. I like that my property manager and I can both monitor my property with the app. The app is pretty easy to use too! Thank you!"

"A 2-in-1 device...Smoke AND Noise

Got my first cigarette alert yesterday. The noise detection was a bit sensitive at first but at least it can be adjusted. I think I will start replacing my Minuts with Sentry as this can detect both smoke and noise."

"It detects ALL smoking and loud noises!

This could definitely help hosts by providing real data for a damages!"

"So hyped about this new device,

About to catch anyone breaking our non-smoking rule WITH EVIDENCE!"


Launching is just a start...

There's no perfect design. Good design is always iterative and on its way. To keep elevating our users' experience with the app, our team sent quarterly survey and I conduct user sessions to gather users' feedback. In addition, we use Mixpanel to track and analyze backend data of the app to gain insights into user behavior, interactions, and preferences within our platform. By examining the data, we can identify areas that require improvement and opportunities to enhance the overall user journey.

Here are new features we added based on users' needs we discovered:

More customizable property settings

In an ideal situation, the possibilities of design are boundless. But in real life, the time, resources, and feasibility might be limited. Hence, as a designer, we need to consider all these factors when making impactful designs.

Property management platform integrations

The integration feature offers users the convenience of mapping imported properties from their preferred platforms to the Sentry. This seamless integration allows for consolidated management, automate the process, and updates of reservation details for each property.

Sentry enterprise web portal

The Sentry web portal is specifically designed for enterprise customers with multiple devices installed like hospitality. Through the web portal, users can easily access and review all the essential information on their desktop.


There's always more to come.

Reflecting on this journey, I found that design is an ongoing process, and there will always be new insights to uncover and needs to discover. Our product is in a constant state of evolution as we strive to make it better, more user-centric, and aligned with the ever-changing needs of our users.

Launching the product is a significant milestone, but it's not the end of the road. It's merely the beginning of a new phase where we continuously learn, iterate, and improve. I hope to deliver the best possible experience to our users drives us to push boundaries and explore innovative solutions.

Embracing this mindset allows us to stay agile and adaptive, always open to feedback and new ideas. It fosters a culture of continuous improvement, where every step forward is an opportunity to grow and learn.

I am excited about the future of our product, knowing that there's always more to come. With each step we take, we move closer to creating a product that truly resonates with our users and makes a positive impact in their lives. Let's embrace the journey ahead with enthusiasm and determination. The possibilities are endless, and I can't wait to see what we'll achieve together!