Company Description

At Open Ring (www.o-ring.tech), we’re behind the world’s first open-source smart ring platform, built for researchers, startups, and developers. We’re building a community-driven ecosystem for wearable tech innovation. As we scale, we’re eager to welcome exceptional talent ready to contribute to a integral movement.

Role Overview

You’ll be one of the core engineers shaping both
firmware and hardware
, working across bring-up, validation, and production readiness. Expect to collaborate daily with our full-stack engineer and founders to turn early prototypes into a scalable, reliable product.

Key Responsibilities
- Develop, maintain, and debug low-power firmware for wearable hardware (BLE 5.x, RTOS or bare metal).
- Lead hardware bring-up on new prototypes validate schematics, review layouts, and help define board revisions.
- Define, test, and validate existing electrical designs; propose improvements for signal integrity, power, and manufacturability.
- Own sensor integration and hardware–firmware interface design (I²C, SPI, UART, GPIO).




- Build and refine factory test firmware and diagnostic tools for CM-level testing and calibration.
- Collaborate closely with the CM for DFM reviews, EVT/DVT/PVT validation, and yield optimization.
- Work hand-in-hand with the mobile developer to verify BLE connectivity, data logging, and end-to-end user experience.
- Contribute to hardware validation test plans, reliability testing, and bring-up documentation.

Qualifications
- 5+ years in embedded firmware and hardware integration (wearables, IoT, or consumer electronics).
- Proficient in C/C++, RTOS (Zephyr) environments, and common MCU architectures.
- Solid understanding of schematics, PCB layout constraints, and debugging hardware issues.
- Experience with BLE 5.x, low-power design, and sensor interfaces.
- Hands-on experience with prototypes, oscilloscopes, logic analyzers, and hardware validation tools.
- Comfortable working directly with manufacturers

📌 Senior Embedded Systems Engineer (Madrid)
🏢 Open Ring
📍 Madrid