Designed a circadian-aligned smart lighting experience that helped 12,000+ users improve their sleep quality by an average of 34% in the first month.
Good evening
Wind down mode
Lumina is a startup building smart LED bulbs that adapt to your circadian rhythm. They had great hardware but their companion app was a feature dump — 47 color presets, manual scheduling, and zero guidance. Users were setting harsh blue-white light at midnight and wondering why they couldn't sleep.
The founder reached out with a clear problem: 70% of users who downloaded the app churned within 2 weeks, and those who stayed reported "confusion" as their #1 complaint in app store reviews. They needed someone to rethink the entire experience from first principles.
I joined as Lead Product Designer with one goal: make the app do the thinking so users don't have to. The light should adapt to biology, not the other way around.
Before touching Figma, I spent two weeks understanding how people actually interact with light in their homes — and what keeps them up at night.
Conducted in-depth interviews with current and former users. Discovered that 85% didn't understand color temperature and just wanted "light that feels right for the time of day."
Analyzed 8 competing apps (Philips Hue, LIFX, Nanolex, etc.). Found that none of them educated users about circadian science — a massive whitespace opportunity.
Partnered with a sleep researcher to understand melatonin suppression curves. Key insight: warm light after 8pm reduces sleep onset latency by 27 minutes on average.
"People don't want to control lights. They want to feel good in their space. The best lighting experience is one they barely notice — it just works with their body's natural rhythms."
Ran user interviews, app store review analysis, and a competitive audit. Created an empathy map that revealed the core tension: users wanted simplicity, but the app offered complexity. I mapped the user's daily light journey and identified 3 critical moments: wake-up, focus, and wind-down.
Redesigned the entire IA from the ground up. Reduced the navigation from 5 tabs to 3. Eliminated 38 of the 47 color presets and replaced them with 4 context-aware "moods" (Focus, Relax, Warm, Bright) that auto-adjust based on time of day. Created low-fidelity wireframes for 12 key screens.
Built a design system with 48 components in Figma. The visual language uses dark mode by default (it's a sleep app, after all), with warm amber accents for active states and cool purple for secondary elements. Created a high-fidelity interactive prototype with 60+ screens and micro-animations for state transitions.
Tested the prototype with 8 participants (mix of new and existing users). Task completion rate jumped from 42% to 89% compared to the old app. Key finding: users loved the "auto mode" but wanted more control over the wind-down schedule. Iterated on the scheduling flow based on feedback.
Prepared comprehensive specs for the engineering team (2 iOS, 1 Android dev). Created Lottie animations for 12 micro-interactions. Ran 3 design QA sessions during development. Launched v2.0 with zero critical design bugs.
Every pixel was intentional. Here are the key design decisions and the reasoning behind them.
The biggest shift was making the app set itself. Instead of presenting 47 color options, the app now defaults to a circadian-aligned schedule. Light temperature shifts automatically from cool white (morning) → neutral (afternoon) → warm amber (evening) → deep red (night).
Users can override anytime, but the default experience requires zero configuration. This single decision reduced onboarding time from 8 minutes to 45 seconds.
Auto Mode
Active
Today's Light Schedule
Current
Warm Amber
Next: Deep Red
in 47 minutes
The old onboarding had 7 screens: account creation, bulb setup, room mapping, schedule setup, color preference, notification settings, and a tutorial. Users dropped off at screen 3.
I redesigned it to 3 screens: location (for sunrise/sunset data), bedtime, and wake time. Everything else is auto-configured. The app learns and adapts over the first week. Onboarding completion went from 31% to 94%.
Before: 7 screens
After: 3 screens
Welcome to Lumina
Let's personalize your light
What time do you usually sleep?
What time do you usually wake?
You can change this anytime
I built a comprehensive design system with 48 components across 6 categories. The system uses CSS custom properties for theming, making it trivial to support the app's dynamic color transitions. Every component has 3 states (default, active, disabled) and supports both light and dark contexts.
Color System
Typography Scale
Buttons
Cards
Warm Light
2700K · 75% brightness
Moonlight
1800K · 20% brightness
Sliders & Controls
Three months after launch, the redesigned app showed dramatic improvements across every key metric.
"I used to spend 10 minutes every night trying to figure out the right light setting. Now I just open the app and it's already perfect. My sleep tracker shows I'm falling asleep 20 minutes faster. This app actually understands what I need."
Sarah R.
Beta tester · 6 months of use
Reducing 47 presets to 4 smart defaults didn't limit users — it liberated them. When you remove decision fatigue, people engage more deeply with the product. The best design is invisible design.
Learning the science of circadian rhythms wasn't just nice-to-have — it was the foundation of every design decision. The best product designers are T-shaped: deep in one area, curious about many.
By making the default experience genuinely useful (auto-circadian mode), we created immediate value on day one. Advanced users can still customize, but they opt in rather than being forced to configure.
Bringing the engineering team into the design process from week 3 meant zero rework during implementation. They understood the "why" behind every component, which led to better technical decisions and faster development.
I'm currently available for freelance and contract work. If you're building something that matters to people, I'd love to hear about it.