Group Project
RE SPF
Academy challenge app that reminds beachgoers when to reapply sunscreen using a custom algorithm.
Project
Group
Platform
iOS
Tech Stack
Swift, SwiftUI, Custom Algorithms, WeatherKit, WatchConnectivity
Role
Backend Developer
What the app does
- Smart Reapply Timer
Dynamic reminders that adjust based on UV index, SPF, and exposure time instead of a generic 2-hour rule.
- Sun Intensity Tracker
Real-time UV data helps you see when the sun is strongest and plan your activities safely.
- Custom Skin Profiles
Personalized suggestions tailored to your skin type, sunscreen SPF, and location.
- Sunscreen Safety Scanner
Instantly scan product labels to check ingredient safety and understand what’s really protecting your skin.
Key takeaways
- Designed and implemented the core algorithm that calculates reapplication timing based on four key factors: UV level, SPF, amount applied, and activity (sweating/swimming). Also supported both frontend and backend development.
- Gained confidence in tackling unfamiliar domains by diving into sunscreen science, researching dermatological guidelines, and translating that knowledge into a functional app feature.
Tech stack
Links
Long story
This project was the 4th challenge in the Apple Developer Academy, which had a theme of helping the local communities in Bali. From our research we found that people in general don't reapply their sunscreens and the general consensus of reapplying every 2 hours is misleading, both of these were crucial problems especially in Bali where the UV can get really high.
Therefore we created an app that helps remind beach visitors when to reapply and to check the ingredients of their sunscreens. My main role in this team is making the algorithm to know when to reapply and helping out in some frontend and backend.
From this project I learned a lot about it. Learn the importance of just believing in yourself and start doing it. Initially I was kind of skeptical if I could make the algorithm, given that I had no prior knowledge in sunscreen or skincare. But after just going with it and actually just writing stuff on the white board, I was able to get into the flow and managed to come up with a scientifically proven algorithm in 1 week.
Turns out there's a lot of factors that goes into figuring out when to reapply the sunscreen, the 4 main ones that we eventually used in our app is the weather (UV level), SPF level of the sunscreen, how much sunscreen is on the skin, and the activity level (when you are sweating/swimming).