Powering Medical-Grade Wearables with Zephyr Expertise: The ActiGraph Success Story

In clinical research, every data point matters. Whether tracking patient mobility after surgery, monitoring activity patterns in neurodegenerative diseases, or measuring treatment efficacy in real-world settings, researchers depend on precise, reliable wearable technology. For ActiGraph, a leader in medical-grade wearables, advancing their technology meant embracing modern firmware architectures while maintaining the rigorous standards required for clinical research. They needed more than just technical contractors—they needed embedded expertise that could become part of their team.

The Vision: Advancing Clinical Research Through Technology

ActiGraph has spent decades building trust in the clinical research community. Their wearable devices are the gold standard for objective physical activity and sleep assessment in thousands of studies worldwide. As they developed their next-generation LEAP device, they recognized an opportunity to modernize their firmware architecture by migrating to Zephyr RTOS.

This wasn’t just a technical upgrade—it was a strategic decision to build on a platform that could evolve with their needs for years to come. The requirements were demanding:

Modern Architecture: Transitioning to Zephyr RTOS on the Nordic nRF5340 System-on-Chip would provide a foundation for advanced features and long-term maintainability.

Regulatory Excellence: Medical device firmware isn’t just about functionality—it’s about maintaining compliance with stringent regulatory standards throughout development and deployment.

Sensor Precision: Integrating accelerometer, PPG, and temperature sensors with the accuracy required for clinical research applications.

Extended Operation: Optimizing power consumption to support long-duration studies without compromising data quality.

Sustainable Development: Building internal capabilities while leveraging external expertise for specialized areas.

Why ActiGraph Chose Croxel

When evaluating partners for this critical initiative, ActiGraph needed more than just Zephyr expertise—they needed a team that understood the unique demands of medical device development. Croxel stood out for several reasons:

Our deep involvement with the Zephyr Project, including active code contributions and Technical Steering Committee participation, meant we didn’t just use Zephyr—we helped shape it. This level of expertise would prove invaluable when navigating the complexities of medical-grade firmware development.

Equally important was our team augmentation philosophy. Rather than working as external contractors delivering code over the wall, we integrate seamlessly with client teams, adopting their processes, standards, and culture. For a medical device company where quality processes are paramount, this approach was essential.

Our track record of long-term partnerships demonstrated that we were invested in our clients’ success beyond individual projects. ActiGraph wasn’t looking for a one-time engagement—they wanted a partner who could grow with them.

Our Solution: Integrated Expertise & Ongoing Partnership

From day one, our approach was about becoming part of ActiGraph’s team while bringing specialized expertise they needed. This wasn’t just about writing code—it was about understanding their product, their market, and their quality requirements.

Seamless Team Integration

We embedded our firmware engineers within ActiGraph’s development organization, participating in their sprint planning, daily standups, and design reviews. By adopting their tools, processes, and communication styles, we became indistinguishable from internal team members—except for the specialized Zephyr expertise we brought to every discussion.

This integration went beyond logistics. We invested time in understanding ActiGraph’s products, their clinical research applications, and the regulatory landscape they navigate. This context made our technical contributions more valuable and aligned with business objectives.

Zephyr RTOS Migration Excellence

The migration to Zephyr RTOS on the Nordic nRF5340 platform required careful architecture decisions. Medical device firmware must balance performance, reliability, and maintainability while providing clear traceability for regulatory purposes.

Our team designed a modular firmware architecture that:

Leveraged Zephyr’s built-in features while maintaining medical device requirements
Provided clear interfaces between system components for easier validation
Implemented robust error handling and recovery mechanisms
Enabled efficient power management without compromising functionality

Throughout the migration, we ensured that existing product capabilities were preserved while building a foundation for future enhancements.

Complex Sensor Integration

The LEAP device integrates multiple sensors critical for clinical research:

Accelerometer: High-frequency motion capture for activity classification and movement analysis PPG Sensor: Photoplethysmography for heart rate and other physiological metrics
Temperature Sensor: Continuous monitoring for environmental and physiological assessment

Each sensor presented unique challenges in terms of timing, data processing, and power optimization. Our expertise in Zephyr’s sensor subsystem allowed us to implement efficient, reliable data collection while maintaining the precision required for research applications.

Regulatory Compliance Focus

Medical device development isn’t just about making things work—it’s about proving they work correctly, consistently, and safely. Our team understood this from the start:

Every design decision was documented with regulatory review in mind
Code was structured to support verification and validation activities
We participated in design reviews with a focus on compliance requirements
Our development practices aligned with ActiGraph’s quality management system

This attention to regulatory requirements meant that our contributions strengthened, rather than complicated, ActiGraph’s compliance posture.

The Partnership Evolution

What began as a firmware migration project evolved into something much more valuable—a true partnership that has now spanned over three years. This evolution happened naturally as both teams recognized the value of continued collaboration.

After the initial migration success, ActiGraph faced new challenges: feature requests from researchers, power optimization opportunities, and emerging connectivity requirements. Rather than ramping up and down with individual projects, our integrated team model allowed us to maintain continuity and deep product knowledge.

The partnership deepened through:

Continued feature development leveraging our Zephyr expertise
Performance optimizations based on field data
Support for new sensor integrations
Knowledge transfer to ActiGraph’s growing internal team

This ongoing engagement meant that ActiGraph always had access to specialized expertise while building their internal capabilities—the best of both worlds.

Measurable Impact

The success of our partnership with ActiGraph can be measured in both technical achievements and business outcomes:

Technical Excellence: The successful migration to Zephyr RTOS created a modern, maintainable firmware platform that has proven robust in clinical deployments worldwide.

Regulatory Success: Throughout our engagement, ActiGraph has maintained their medical device compliance, with our contributions strengthening their development processes.

Optimized Performance: Power optimization efforts extended battery life for multi-day studies while maintaining the high-frequency data collection researchers require.

Accelerated Development: With integrated Zephyr expertise, ActiGraph has been able to implement new features faster, responding to researcher needs more quickly than ever before.

3+ Years of Partnership: The longevity of our engagement speaks to the value delivered—this isn’t just about technical capability, but about becoming a trusted part of their team.

Perhaps most importantly, ActiGraph has been able to focus on their core competency—understanding and serving the clinical research community—while having confidence that their firmware development is in expert hands.

Looking Forward

The ActiGraph success story demonstrates the power of true technical partnership. By integrating specialized expertise directly into their team, ActiGraph gained more than just Zephyr knowledge—they gained a committed partner invested in their success.

This model of embedded expertise represents the future of technical collaboration. Rather than the traditional contractor model with its overhead and communication challenges, integrated partnerships deliver:

Immediate productivity without lengthy onboarding
Deep product knowledge that grows over time
Seamless collaboration that preserves company culture
Flexible access to specialized skills
Continuous value delivery rather than project-based peaks and valleys

For companies developing sophisticated embedded systems—whether medical devices, IoT products, or industrial equipment—the message is clear: you don’t have to build every capability internally. The right partner can integrate with your team, bringing specialized expertise while respecting your processes and culture.

Is your team ready for integrated firmware expertise?

Whether you’re planning a Zephyr migration, need to accelerate development, or require specialized embedded systems knowledge, Croxel’s team augmentation model delivers the expertise you need with the integration your team deserves.

Explore our Engineering Services to learn how we can strengthen your development capabilities.