BLE · Low-Power Embedded
Bluetooth-Enabled Personal Safety Device
Overview
Designed and developed a compact Bluetooth-enabled personal safety device integrating wireless communication, high-intensity LED signaling, audible alarms, haptic feedback, battery management, and smartphone connectivity for rapid emergency notification.
The engineering challenge
Develop a compact, battery-powered emergency device capable of immediately attracting attention through multiple alert mechanisms while simultaneously communicating with a companion smartphone application for location sharing and emergency notification.
Confidential Prototype
BLE Personal Safety Device — proprietary prototype; imagery withheld at the client's request.
- Microcontroller
- Nordic nRF52840
- Connectivity
- Bluetooth Low Energy (BLE) · USB-C
- Integrated Hardware
- Piezo alarm · RGB LEDs · Haptic motor · Battery charger · Battery protection · Battery monitoring
- Firmware
- Embedded C · Zephyr RTOS
What I owned
- Designed complete electronic hardware including schematics and PCB layouts
- Selected electronic components and optimized PCB layout for compact packaging
- Integrated Bluetooth Low Energy communication
- Developed embedded firmware using the Zephyr RTOS
- Performed PCB assembly and hardware bring-up
- Debugged firmware and board-level hardware issues using SWD debugging tools
- Supported manufacturing validation and prototype testing
- Assisted with mechanical integration and enclosure validation
System architecture
Full technical specification
- Microcontroller
- Nordic nRF52840
- Connectivity
- Bluetooth Low Energy (BLE)USB-C
- Integrated Hardware
- Piezo alarmRGB LEDsHaptic motorBattery chargerBattery protectionBattery monitoring
- Firmware
- Embedded CZephyr RTOS
- Development Software
- Fusion 360 ElectronicsVisual Studio CodenRF Connect SDKGit
- Debug Tools
- J-Link debugger
Development process
- 01Requirements Definition
- 02System Architecture
- 03Electronic Design
- 04PCB Layout
- 05Prototype Assembly
- 06Firmware Development
- 07Bluetooth Integration
- 08Hardware Bring-up
- 09Debugging
- 10Validation & Testing
- 11Production Prototype
Engineering challenges
- Optimizing PCB layout within a compact enclosure
- Debugging SWD programming and reset circuitry
- Implementing reliable Bluetooth communication while maintaining low power consumption
- Integrating battery charging, protection, and monitoring circuitry
- Validating prototype reliability during manufacturing and hardware bring-up
Skills demonstrated
Outcome
Delivered a fully functional prototype integrating Bluetooth communication, emergency notification, high-intensity LED signaling, audible alarms, vibration feedback, and battery-powered operation within a compact portable enclosure.