Safety Band & App Coding

I have a wearable safety band prototype that must deliver reliable health monitoring, starting with continuous heart-rate tracking. Your task is twofold: write the embedded firmware that runs on the band and create the companion mobile application. On the firmware side, you will read the heart-rate sensor, filter and average the data, manage power, and broadcast everything over Bluetooth Low Energy. I will supply the full hardware schematic, sensor datasheets, and preferred MCU (nRF52 series) once we begin. For the software side, I need a user-friendly companion app that pairs with the band, shows real-time and historical heart-rate graphs, stores data locally, and syncs to a cloud back-end. It must be ready for both iOS and Android, so you can choose native (Swift / Kotlin) or a single cross-platform stack such as Flutter or React Native, provided performance and UI guidelines remain solid. Push alerts for abnormal readings, background data collection, and an export-to-CSV option round out the core features. Deliverables • Well-commented firmware source code compatible with my hardware, plus flashing instructions • Complete iOS and Android apps (or unified codebase) with build documentation • Simple dashboard: live heart rate, daily averages, CSV export • README covering setup, API, and testing procedures Acceptance criteria – Heart-rate accuracy within ±3 bpm of reference device – BLE link stability above 95 % during continuous 8-hour operation – Apps meet App Store and Play Store submission requirements without blockers If you’re comfortable handling both low-level BLE firmware and modern mobile development, let’s turn this prototype into a polished, production-ready solution.