I am seeking a skilled React Native developer to build a Minimum Viable Product (MVP) for a mobile app that will track and analyze how Brazilian Jiu-Jitsu athletes train. This app will connect to a custom wearable IMU sensor to provide athletes with objective, data-driven insights into their performance.
You will be responsible for building the first version of the app for both iOS and Android using React Native. The core function of the app is to connect via Bluetooth Low Energy (BLE) to the IMU sensor, process its data into five key performance indicators, and display them in a simple, functional user interface. For this MVP, I want to prioritize core functionality and data accuracy over complex visual design. This does NOT need a nice UI.
Core MVP Features:
The app will have a simple 3-tab navigation structure:
Tab 1: Daily Dashboard
Display five consolidated metrics from the user's most recent training session:
Work Rate Score
Daily Impact Load
Positional Dominance Score
Performance Decay (%)
Takedown Quality Score (/100)
Tab 2: Performance Trends
Display charts showing the user's average for the same five metrics over a 7-day and a 30-day period.
Tab 3: Record & Tagging Station
Record Match: A feature to initiate video recording using the phone's camera while simultaneously starting a data-logging session with the IMU sensor.
"In-App Lite" Tagging: A simple interface where users can watch their recorded video and tap event buttons (e.g., [Takedown], [Sweep]). Your code must capture the timestamp of the tap and use an algorithm to link it to the nearest significant event in the sensor's data stream.
Technical Requirements & Specifications:
Platform: React Native for cross-platform support on both iOS and Android.
Hardware Integration: The app will connect via Bluetooth Low Energy (BLE) to a custom IMU sensor based on the STMicroelectronics LSM6DSV320X. This is a mandatory requirement.
Data Processing: The developer will be responsible for implementing the algorithms to calculate the five consolidated scores. The BJJ-specific logic, rules, and weighting for these formulas will be provided by me.
Data Storage (Local-First MVP): For this initial version, all user data (metrics, tagged events, videos, and demographic info) must be stored locally on the user's device. No cloud backend or user account system is required at this stage.
User Profile (Local): The app must have a simple, local-only profile screen where users can input their demographic information (Sex, Belt Rank, Age, Training Frequency, Weight). This data will be saved on the device for future use.
Future-Proof Design (Critical):
Hardware Abstraction Layer (HAL): The app's communication layer must be architected to be independent of the sensor hardware, allowing for different hardware to be used in the future without a full rebuild.
Scalable Architecture: The app must be designed with the future in mind. I plan to add user accounts, a cloud backend for data synchronization, and AI-driven workout suggestions in Version 2.0. The MVP's architecture must be modular to support these future features without requiring a complete rewrite.
What I'll Provide:
Clear product requirements and user stories.
The detailed logic and weighting for the custom metric formulas.
A fully functional prototype of the IMU sensor hardware for development and testing, which will be shipped to you (if needed)
What I'm Looking For in a Developer:
Proven experience building and deploying production apps with React Native.
Demonstrable experience working with Bluetooth Low Energy (BLE) is essential. Please provide specific examples of previous BLE projects.
Experience with IMU sensor data, data visualization, and/or sports analytics apps is a strong plus.
Experience in Brazilian Jiu Jitsu or Wrestling is a PLUS
A strong understanding of mobile app architecture for scalability and future-proofing.
Excellent communication skills and the ability to work with a non-technical product owner.
COMPLETE SPOKEN fluency in English to properly convey updates and answer questions
How to Apply:
Please include the following in your proposal:
A brief summary of your React Native and BLE experience as it relates to this job posting
Your proposed technical approach for building this MVP, specifically addressing the local-first storage and the architecture for future scalability.
A ballpark estimate for the project's cost and timeline.
Links to relevant apps in the App Store / Google Play you have built.
NeoForge Limestone Block Variants Category: Game Design, Game Development, Game Testing, Java, JSON, Minecraft, Software Development, Software Engineering Budget: $250 - $750 CAD
24-Aug-2025 10:04 GMT
Multilingual Hotel Investment Website Category: Content Management System (CMS), Graphic Design, HTML, SEO, Web Design, Web Development, WordPress Budget: €2 - €6 EUR
Document Proofreading in Spanish Language Category: Content Writing, Copy Editing, Editing, English (US) Translator, Language Tutoring, Linguistics, Proofreading, Spanish Translator, Spanish Tutoring, Translation Budget: ₹600 - ₹1500 INR
24-Aug-2025 10:00 GMT
US Footwear Sales Strategy Development Category: Brand Management, Business Analysis, Business Development, Digital Marketing, Internet Marketing, Market Analysis, Market Research, Marketing Budget: $8 - $15 USD
Application development Category: API Development, Backend Development, Cloud Development, Database Management, Mobile App Development, Python, Software Development, User Interface / IA, Web Application Budget: ₹250000 - ₹500000 INR
24-Aug-2025 09:58 GMT
Zen Cart Payment Module Development Category: API Integration, ECommerce, MySQL, Payment Processing, PHP, Software Architecture, Software Development, Zen Cart Budget: $20 - $100 USD
24-Aug-2025 09:56 GMT
Crypto Grabber Development Category: API Integration, Blockchain, C, Programming, Cryptocurrency, JavaScript, PHP, Software Architecture, Software Development Budget: ₹600 - ₹1500 INR
24-Aug-2025 09:54 GMT
Hindi Love Song Writer Category: Audio Production, Audio Services, Creative Writing, Hindi Translator, Music, Music Production, Poetry, Romance Writing Budget: ₹750 - ₹1250 INR
24-Aug-2025 09:52 GMT
Organic Cooking Channel Subscriber Boost Category: Content Creation, Content Marketing, Facebook Marketing, SEO, Social Media Management, Social Media Marketing, Twitter, Video Editing, YouTube Budget: ₹600 - ₹1500 INR
24-Aug-2025 09:50 GMT
Seeking a talented Native Spanish Subtitle Translator Category: Castilian Spanish Translator, Editing, English (US) Translator, Language Tutoring, Linguistics, Proofreading, Spanish Translator, Subtitles & Captions, Translation, Video Services Budget: $250 - $750 USD
24-Aug-2025 09:50 GMT
Twitter Sentiment Analysis with AI Category: Data Mining, HTML, Java, Machine Learning (ML), Natural Language Processing, NumPy, Pandas, Python, Sentiment Analysis, Streamlit Budget: ₹12500 - ₹37500 INR
