Wearable Heart-Rate Monitor Firmware & App Development

@Microlent

Hello, I am Dr. Rajesh Rolen, PhD in Computer Science & Engineering, with experience of over 20+ years in Android, Mobile App Development, iPhone As a preferred freelancer in the top 1%, I have done 400+ projects here on freelancer.com, I have 4.9 ratings out of 5 on average, which showcases my quality of work and timely delivery. Key Highlights: - Free Hosting Support on the Cloud or any desired platform. - Free 3 months of post-delivery support to ensure that our client doesn’t face any challenges after the launch of the project. - Free Dedicated tester on projects to ensure quality delivery, so clients don’t need to act as a tester. - 10+ Years experience UI/UX team to ensure intuitive UI. Portfolio: https://www.freelancer.com/u/Microlent Please open the chat and send me a message, so we can have a more detailed discussion about the project to give you the project timeline and cost. Thank you for considering my services. I look forward to engaging in a productive conversation and understanding how I can be of assistance in bringing your project to life. Regards Rajesh Rolen

@om26er

Hello, i have Samsung Galaxy Watch 8(40mm) and Galaxy Watch 4 Classic(44mm) and i have already developed Heart Rate (BPM) Moniter, i can show you sample source code as well. Let's chat to proceed.

@corpmember29

Hello, Wearable Health Monitoring & BLE Developer I HAVE CREATED SIMILAR BLE, IOT AND HEALTH MONITORING SYSTEMS BEFORE AND I CAN SHOW YOU I went through your requirements and understand that you need both nRF52 firmware and companion iOS/Android apps for continuous heart-rate monitoring. I have 11+ years of software development experience and can develop the firmware to read the heart-rate sensor, filter/average readings, manage power efficiently, and transmit reliable data over BLE. I will also handle BLE connection stability, sensor validation, logging, and flashing/setup documentation. For the mobile side, I can build a Flutter or React Native app with secure BLE pairing, real-time and historical heart-rate graphs, local data storage, cloud synchronization, background collection, abnormal-reading push alerts, daily averages, and CSV export. I will test the complete firmware-to-app workflow against your reference device and target the stated ±3 BPM accuracy and 95%+ BLE stability over continuous operation. I will also provide clean source code, API/README documentation, testing procedures, and App Store/Play Store build support. I WILL PROVIDE 2 YEARS OF FREE ONGOING SUPPORT AND COMPLETE SOURCE CODE. WE WILL WORK WITH AGILE METHODOLOGY AND WILL ASSIST YOU FROM ZERO TO PUBLISHING ON STORES. Thanks, Christina

@DrSyafiq

I can take this from scope to a tested handoff without bloating the first milestone. For a Wearable Heart-Rate Monitor Firmware & App Development, the hard part is balancing sensor scanning accuracy, battery life, Bluetooth/SIM fallback, and OTA-ready embedded reliability. My approach would be to validate the sensor matrix and power budget first, then design the acquisition PCB, embedded firmware, connectivity fallback, and OTA/admin controls in staged prototypes. Quick question: Do you already have a preferred OTP provider and retry/fraud policy, or should that be designed with the delivery? Also, do you already have the API and screen designs, or should the first milestone define the end-to-end mobile flow? Best, Dr. Syafiq

@amelectronics

Hi, I have experience in designing Circuits and can complete your project. I have expertise in the following: 1- Designing schematic and PCBA 2- Ordering the PCBA and getting boards manufactured. 3- Writing firmware for the PCBA to make sure everything works as expected. 4- I can also develop smartphone apps to communicate and control the hardware. If you wish we can discuss in chat. Thank you.

@Hammadhassan21

Hey, If you need reliable heart rate data in real world use, the key is getting the nRF52 firmware, BLE connection, and mobile app working together as one stable system rather than treating each part separately. I can work from your nRF52 hardware specifications to build the firmware around sensor filtering, averaging, power management, and reliable BLE communication, then connect it with a cross platform mobile app supporting live and historical graphs, local storage, cloud sync, alerts, and CSV export. I’ll also focus on making the data flow reliable during continuous use and background syncing. The ±3 bpm accuracy and 8 hour BLE stability targets should be validated through structured testing against your reference device rather than simply assumed. This will help identify any issues with sensor readings, BLE stability, power usage, or data synchronization before the final build. I can show relevant firmware, BLE, IoT, or mobile app examples in chat. Once you share the sensor datasheet and schematic, I can review the hardware and BLE/data flow and suggest the right implementation approach before development starts. Portfolio: https://www.freelancer.com/u/Hammadhassan21 Best regards, Hammad Hassan

@AITSoft

Hi, I understand that you need firmware for an nRF52 wearable band and companion iPhone and Android apps. I would handle heart-rate sensor readings, filtering, averaging, power use, and stable Bluetooth Low Energy communication. The app would show live and historical readings, save data locally, sync with the cloud, send abnormal-reading alerts, collect data in the background, and export CSV files. I would first review the hardware schematic, sensor datasheet, MCU setup, and reference device. Then I would build and test the firmware and app together, focusing on the ±3 bpm accuracy target, reliable BLE operation during long runs, and store submission requirements. I will also provide commented source code, build and flashing steps, API details, testing notes, and a clear README. Which heart-rate sensor, cloud backend, and preferred Android technology do you plan to use, and is the reference device already selected? I can use Swift for the iOS side and ensure the Android app follows the same data flow and user experience.

@ciss26

Hello there, Hope you are doing well We can help you develop the complete wearable heart-rate monitoring solution, covering both the nRF52 firmware and the iOS/Android companion application. We are Cyber Impulse Software Solutions, with experience across IoT, BLE-connected devices, mobile apps, cloud APIs, real-time data, notifications, and embedded integrations. Proposed Tech Stack - Firmware: C/C++ with Nordic nRF5 SDK / Zephyr / nRF Connect SDK - MCU: nRF52 Series - Communication: Bluetooth Low Energy (BLE) - Mobile App: Flutter for iOS & Android - Backend: Node.js / NestJS - Database: PostgreSQL / Firebase Key Features Firmware - Heart-rate sensor integration - Continuous sampling - Signal filtering and averaging - BLE services and characteristics - Power optimization - Battery monitoring - Background data broadcasting - Error handling and reconnection logic - Firmware flashing/setup documentation Mobile App - BLE device discovery and pairing - Real-time heart-rate display - Historical heart-rate graphs - Daily averages - Local data storage - Cloud synchronization - Background monitoring - Configurable abnormal-reading alerts - Push notifications - CSV data export - Device/battery status - User-friendly Android & iOS UI Thanks & Regards Dheeraj K.

@p4logics

Hello Sir, I understand your requirement to build a production-ready wearable safety band system featuring low-level nRF52 firmware for continuous heart-rate monitoring with BLE broadcasting, paired with a cross-platform Flutter mobile app for real-time tracking, local storage, and cloud sync. To deliver this, I will implement optimized embedded C/C++ firmware for efficient sensor filtering and power management, along with a robust Flutter app featuring reactive state management, background sync, BLE pairing, and clean CSV export capabilities to meet your exact acceptance criteria.

@tshibsamuel477

Hi there, I carefully reviewed your wearable safety-band project, including continuous heart-rate acquisition, signal filtering, power management, BLE communication, real-time/historical visualization, cloud synchronization, and the required iOS/Android companion application. I am a mechatronics engineer with almost half a decade of experience in embedded electronics, hardware prototyping, microcontroller-based systems, sensors, and interfaces such as SPI, I2C, UART, and USB. My background is particularly relevant to integrating the heart-rate sensor with the embedded platform, managing reliable data acquisition, and optimizing the firmware/hardware interaction for a low-power wearable device. I understand that this project also requires rigorous validation against a reference heart-rate device, long-duration BLE stability testing, and complete documentation for firmware, APIs, setup, and testing. My embedded-systems experience allows me to approach the device-side development and integration efficiently while keeping the implementation structured for production-oriented testing. Please send me a message so we can discuss the project and start. Best regards, Samuel tshibangu

@MuhammadUzair16

Hi, I am an embedded systems engineer with over 16 years of experience developing connected products, including low-power sensor firmware, nRF52 BLE systems, signal processing, mobile apps, and cloud-connected dashboards. I can handle the complete path from your safety-band prototype to a reliable, consumer-grade solution. I will develop well-documented firmware for continuous sensor acquisition, filtering, averaging, power management, and stable BLE communication, alongside a polished cross-platform mobile app for iOS and Android. The app will provide live and historical graphs, local storage, cloud synchronization, background collection, abnormal-reading alerts, and CSV export. I will also provide flashing, build, API, testing, and deployment documentation. My approach includes comparison against your reference device, extended BLE soak testing, and early checks for App Store and Play Store requirements. I can also help review the electronics, battery performance, production readiness, and future safety features where useful. Which heart-rate sensor and cloud platform are you using, and is the abnormal-reading logic already defined? The quoted schedule assumes the hardware is available and operational at kickoff. Please contact me to discuss details.

@mahig47

Hello, I have 7+ years of experience in mobile and full-stack development and can handle both the nRF52 wearable firmware and the companion iOS/Android application. I’ll develop the firmware to read and process the heart-rate sensor, apply filtering/averaging, manage power efficiently, and provide reliable BLE communication. Nordic’s nRF52 platform supports BLE and low-power operation, making it suitable for this type of wearable implementation. For the mobile side, I can build a clean cross-platform app with device pairing, real-time and historical heart-rate graphs, local data storage, cloud synchronization, background collection, abnormal-reading push alerts and CSV export. I’ll also cover testing, BLE stability, documentation, build instructions and App Store/Play Store readiness. The ±3 BPM accuracy and 8-hour BLE stability requirements can be included as measurable validation criteria against your reference device and hardware setup. PLEASE INITIATE CHAT SO I CAN SHARE MY RELEVANT MOBILE, BLE AND IOT PROJECTS. Best Regards, Nikita Gupta

@zainalitariq245

Hey there, I understand this needs both reliable nRF52 firmware for continuous heart rate sensing, filtering, power management, and BLE, plus a companion app covering live readings, history, cloud sync, alerts, background collection, and CSV export. I would keep the firmware and mobile layers modular, with clear BLE data handling and power conscious sampling. For the app, Flutter would provide one maintainable codebase for iOS and Android, while keeping storage, sync, alerts, and graphs separated for easier testing against your accuracy and 8 hour BLE requirements. One question: do you already have a preferred cloud backend and heart rate sensor selected, or should those interfaces remain configurable until the hardware details are provided? Looking forward to working together. My portfolio and client reviews, https://www.freelancer.com/u/zainalitariq245 Best regards, Zain Tariq.

@Eliteinno

Targeting an nRF52 series chip while simultaneously building the cross-platform mobile layer means the central challenge is designing a clean GATT service structure that handles background BLE syncing on iOS without dropping packets. Flutter handles the dual platform app requirement cleanly here, especially for local SQLite storage and charting packages, while the firmware side will need careful power profiling during continuous sensor reads. Are you using a specific PPG sensor module for the heart rate data, or is that part still open?

@melikatfz

Hi there, Building a reliable safety wearable is challenging because maintaining stable BLE connectivity during continuous 8-hour monitoring while optimizing battery drain on an nRF52 chip often leads to dropped packets or sensor lag, but my expertise in low-level embedded firmware and cross-platform mobile architecture ensures your device will stream real-time data flawlessly with over 95 percent link stability and sub-three bpm accuracy. Here are my questions: 1. Which specific heart-rate sensor IC are you utilizing in the hardware schematic? 2. Do you have a preferred cloud back-end stack already set up for data synchronization? Let's discuss your project now!

@invoketech

Hello, I checked your job post and understand that you need an end-to-end wearable solution covering nRF52 firmware, BLE communication, and a companion iOS/Android application for continuous heart-rate monitoring. Key features: nRF52 firmware and heart-rate sensor integration Signal filtering, averaging and power optimization Reliable BLE communication and reconnection Flutter-based iOS & Android app Real-time and historical heart-rate graphs Local storage with cloud synchronization Background data collection and abnormal-reading alerts CSV export and daily health summaries Firmware flashing, testing and technical documentation I have 10+ years of experience in mobile and connected-device development, including BLE-based applications and hardware integrations. I can handle the complete flow from sensor data acquisition and firmware processing to BLE transmission, mobile visualization and cloud sync. Let we connect over call/chat for detail discussion. Thanks, Invoke Tech

@Jennycreation

Hello Sir, I have already worked on similar types of website and software development projects and I am confident that I can successfully handle your project. I am a full-time freelancer with **17+ years of experience** in web development, software development, automation, and API integrations. My expertise includes: * Android app development * ASP.NET C# web and software development * Python automation and web scraping (Amazon, Instagram, Facebook, Google Maps, LinkedIn, Telegram, and other custom scraping solutions) * JavaScript, jQuery, AJAX, Bootstrap, HTML5 * Microsoft SQL Server database development * Payment gateway integration * SMS, Email, Banking, Financial, and Insurance API integration * Custom automation bots and workflow automation software I focus on delivering **high-quality, scalable, and reliable solutions** with clean code and long-term support. Please contact me in private chat so we can discuss your requirements in detail. I can also show you a **demo of similar projects** I have completed. Looking forward to working with you. Thanks & Regards

@tonybhsl

Hello, We can help develop the wearable firmware and companion iOS/Android application around your nRF52 hardware and BLE requirements. Our Approach: nRF52 firmware for heart-rate sensor acquisition Signal filtering, averaging and power-management logic Stable BLE communication and reconnection handling Flutter-based iOS + Android companion app Real-time and historical heart-rate visualization Local data storage with cloud synchronization Background BLE data collection and push alerts Daily averages and CSV export API/backend integration and secure data handling Firmware flashing instructions, README and build documentation Device/app testing against your reference hardware We can structure testing around your ±3 BPM accuracy and 95%+ BLE stability acceptance criteria, validating performance with the supplied sensor and reference device. We have 19+ years of software development experience and can begin with a hardware/firmware review once the schematic, sensor datasheet and MCU details are provided. Best regards, Bivanshi Ohri

@laraibfatima399

Hi, I can help develop your wearable safety band end to end, covering nRF52 firmware and a cross-platform Flutter application for iOS and Android. I’ll implement heart-rate acquisition, filtering, power optimisation, stable BLE communication, real-time and historical graphs, local storage, cloud synchronisation, alerts, and CSV export. I’ll also provide documented source code, flashing/build instructions, and testing procedures. I recommend a milestone-based approach, with hardware integration, BLE stability, and heart-rate accuracy validated against your reference device before final delivery.