Gringo

💍 Smart BLE Ring Project

🧠 Team

• 🛠️ Hardware Engineers: Mathys Pellen, Pierrick Simon
• 👨‍💻 Software Engineers: David Cartier, Marius Chritin

📜 Project Description

Development of an ultra-compact smart ring integrating:

• Bluetooth Low Energy (BLE) communication
• Heart rate (BPM) measurement
• Activity and movement tracking
• Sleep monitoring
• Skin temperature measurement

Mobile application dedicated to:

• Real-time collection of biometric data
• Visualization and analysis of health information
• Synchronization with Samsung Health using Health Connect API

🛠️ Project Architecture

Hardware

• Microcontroller: nRF5340 (Nordic Semiconductor)
• Main Sensors:
  • MAX86150: Heart Rate and SpO2
  • BHI260AP: 6-axis IMU (motion detection)
  • MAX30205 (or equivalent): Skin temperature sensor
• Charging: Wireless charging with Qi standard (STWLC38 IC)
• PCB: Flexible PCB (FPC) for compact integration into a ring
• Casing: Titanium ring, machined or 3D printed

Software

• Embedded firmware:
  • Developed with nRF Connect SDK (Zephyr RTOS)
  • Standard BLE GATT communication
  • OTA DFU (Firmware update over Bluetooth) supported
• Android Application:
  • Developed with Android Studio
  • BLE Central communication
  • Integration with Samsung Health via Health Connect

📂 Project Folder Structure

/README.md           → Main project documentation
/HW/                 → Hardware designs (schematics, PCB layouts, datasheets)
                     → 3D models of the ring (STEP, STL, F3D formats)
/SW/                 → Embedded firmware for nRF5340 (Zephyr)
                     → Android Studio mobile app project
/doc/                → Specifications, technical documents, research notes

🧩 Technologies and Tools

• nRF Connect SDK (Zephyr RTOS, Nordic Semiconductor)
• Segger Embedded Studio or VS Code + nRF Connect Extensions
• KiCad for PCB design
• OnShape / SolidWorks for 3D modeling
• Android Studio for mobile app development
• GitHub for project management and version control

📈 Roadmap

• Requirements and specifications definition
• Component selection
• BLE basic firmware development
• BLE mobile application creation
• First prototype PCB design
• Hardware prototype fabrication
• Full system integration and testing
• Low-power optimization
• Final miniaturization and industrialization

⚡ Inspirations

• Samsung Galaxy Ring
• Oura Ring Gen 3