Simbex is seeking a Senior Embedded Systems Engineer to own the full hardware-firmware stack for a next-generation IoT wearable platform. This is a dual-discipline role: you will independently design and develop embedded hardware circuits and PCBs alongside production-grade Zephyr RTOS firmware - from component selection and schematic capture through board bring-up, sensor integration, and field deployment. The ideal candidate is a hands-on engineer who takes end-to-end ownership in building sensor-based hardware and firmware.
Essential Functions: Electrical Engineering & Hardware Development
Own hardware design from component selection and schematic capture through PCB layout review and design-for-manufacture
Lead board bring-up: power sequencing, peripheral initialization, signal integrity verification, and fault isolation
Design and characterize low-power analog front-ends and power management subsystems for battery-operated wearables
Develop hardware test fixtures and produce electrical characterization reports
Firmware Architecture & Development
Architect and deliver production Zephyr RTOS firmware on ARM Cortex-M/R targets
Author device drivers, BSPs, and devicetree overlays; implement sensor acquisition pipelines for IMU-based impact detection
Design low-power state machines and event-driven architectures for wearable operation
Set firmware coding standards, CI/CD pipelines, and architecture guidelines for the team
IoT & Wireless Connectivity
Implement BLE stacks for real-time telemetry and configuration; design OTA update mechanisms via MCUboot
Integrate cloud connectivity (MQTT/CoAP) and evaluate edge vs. cloud trade-offs for impact detection
Signal Processing & Algorithm Integration
Port impact detection algorithms from MATLAB or Python into constrained C/C++ firmware
Apply sensor fusion (Madgwick, Mahony, complementary filter) for accurate head kinematics from multi-axis IMU data
Optimize DSP routines for speed and memory footprint on resource-constrained targets
Testing & Quality
Define and execute unit, HIL, and system integration test plans; build automated regression frameworks
Maintain design documentation, traceability matrices, and test reports; support compliance activities
Required Qualifications:
BS or MS in Electrical Engineering, Computer Engineering, Embedded Systems, or related field
7+ years of embedded development experience, including 3+ years on production-shipped products
Hands-on EE skills: independently read schematics, perform board bring-up, and debug hardware/firmware interaction
Proficiency with bench instrumentation (oscilloscope, logic analyzer, power analyzer) for power characterization and debug
Experience selecting microcontrollers, RF SoCs, and sensor ICs (IMU, accelerometer, gyroscope) for product designs
Strong C/C++ in bare-metal and RTOS-based embedded contexts
Demonstrated Zephyr RTOS experience: devicetree, Kconfig, module system, and west toolchain
Experience with ARM Cortex-M SoCs (Nordic nRF52/nRF53, STM32, or similar) and peripherals: SPI, I2C, UART, USB
BLE firmware experience and familiarity with OTA update workflows (MCUboot preferred)
Preferred Qualifications:
Sensor fusion algorithm experience (Madgwick, Mahony) and algorithm porting from MATLAB/Python
Exposure to sports biomechanics, head impact research, or wearable athletic sensing
Cloud IoT platform experience (AWS IoT Core, Azure IoT Hub) and embedded security (TLS/DTLS, secure elements)
Multi-core SoC development (e.g., nRF5340) or experience in a regulated/safety-critical product environment