Wearable BLE Smart IoT Ring Development with Nordic nRF52

The organization was an American technology start up focused on developing next generation, battery operated smart rings for both the wearable industry and the lifestyle category. Their product had just entered the Engineering Verification Test phase. At this stage, firmware stability, power efficiency, and the ability to bring up and validate the hardware were critical to the product’s success.

The smart ring was designed for minimalism, discretion, and ultra-low power while still being capable of supporting the user by means of functional interaction such as touch actions, haptic feedback and LED indicators. The client engaged Adequate Infosoft to act as their embedded BLE firmware development partner, responsible for defining the firmware foundation and supporting EVT readiness.

The primary goals of the engagement were:

• Design scalable core firmware architecture for a BLE smart ring
• Support nRF52-class MCUs, with flexibility before final MCU selection
• Implement multiple firmware modes with gesture-based switching
• Optimize power consumption for continuous wearable use
• Support EVT bring-up and early hardware validation
• Prepare firmware suitable for future DVT and PVT phases

The solution developed by Adequate Infosoft is an integrated multi-access smart lock system, consisting of hardware, embedded firmware, cloud and applications powered by Nordic Semiconductor Controllers.

Access Methods Implemented

Limitations of an Ultra-Low Power Wearable

The smart ring must comply with stringent size and battery constraints when compared to watches and bands. Therefore every sub-system in the smart ring must be optimized carefully for no additional power loss due to excessive consumption.

Gesture-Based Interaction without a Screen

The ring relied heavily on capacitive touch gestures rather than a display. This required:

• Reliable touch detection
• Noise filtering
• Gesture differentiation
• Low-latency response without keeping the MCU fully active

Flexibility of MCU Selection

The final MCU was not locked; therefore the firmware must remain portable across all nRF52 class devices. Hard dependencies on specific hardware will negatively affect the ability to make hardware decisions in a timely fashion.

The solution supports:

• Nordic nRF52 class microcontrollers
• EVT hardware revisions
• Future feature growth without needing to rebuild systems from the ground-up

Core Firmware Framework

We implemented a lightweight embedded architecture with:

• Event-driven task handling
• Low-power state machine design
• Clear abstraction for sensors, haptics, LEDs, and BLE

The architecture allowed individual features to wake the system only when required, maximizing sleep time.

Power Management Strategy

• Aggressive use of sleep and deep-sleep modes
• Peripheral power gating
• BLE connection parameter optimization
• Interrupt-driven wakeups for touch events

This approach ensured the ring remained power-efficient even with frequent interactions.

BLE Communication Development

BLE was implemented using nRF52-class BLE stacks, designed for:

• Stable advertising and reconnection
• Secure pairing and bonding
• Minimal data payloads to reduce radio usage

BLE communication enabled

• Mode status updates
• Configuration changes
• Future companion app integration

All BLE services were structured for long-term scalability.

Gesture Detection & Mode Switching

Gesture detection was a core feature of the product.

Capacitive Touch Handling

Adequate Infosoft implemented:

• Touch signal filtering
• Debounce and false-trigger prevention
• Gesture pattern recognition

V1 firmware included three operational modes:

Swipe Mode

• Detects directional swipe gestures
• Used for navigation and interaction
• Fast response with minimal power impact

Shower Mode

• Designed to prevent false triggers due to water
• Touch sensitivity dynamically adjusted
• Firmware locked into a stable interaction state

Calm Mode (Haptic Breathing Rhythm)

• Generates rhythmic haptic feedback
• Timing-based vibration patterns for breathing guidance
• Carefully optimized duty cycles to reduce power usage

Mode switching was handled entirely through gesture-based input, without buttons or displays.

Haptic Feedback

• Precision control of vibration motor timing
• Smooth intensity transitions
• Pattern-based feedback tied to firmware modes

LED Feedback

• Low-power LED signaling
• Status-based visual feedback
• Controlled brightness and duty cycle

Both subsystems were tightly integrated with power management to ensure they were active only when needed.

Adequate Infosoft worked closely with the client during EVT bring-up, supporting:

• Initial board validation
• Peripheral bring-up and pin mapping
• Debugging early hardware issues
• Firmware updates aligned with PCB revisions

The firmware was structured to adapt quickly to hardware changes, reducing EVT iteration time.

Testing focused on:

• Power consumption profiling
• Gesture accuracy under real-world usage
• BLE stability across multiple devices
• Long-duration idle and interaction tests

Issues discovered during testing were resolved before EVT sign-off.

• EVT-ready firmware successfully delivered
• Stable BLE communication achieved
• Gesture-based interaction validated
• Ultra-low power performance confirmed
• Firmware architecture ready for DVT expansion

The client gained a solid firmware foundation for their smart ring, significantly reducing technical risk for future development stages.

Following the successful EVT phase, the client initiated discussions with Adequate Infosoft for:

• DVT and PVT firmware support
• Companion mobile app integration
• Manufacturing test firmware
• Feature expansion and optimization

This project established Adequate Infosoft as a trusted embedded wearable engineering partner.

This case study presents an example of how Adequate Infosoft has developed expertise in providing BLE wearable’s firmware for nRF52-class & ultra-low power devices. Through a structured firmware architecture, gesture-based interaction, combined with our EVT-focused delivery methodology, we assisted the client in moving confidently to manufacturing readiness.