Senior Hardware & Embedded Systems Engineer

About Lumysi

Lumysi is a US-based wearable technology startup developing a jewelry-inspired health and fitness bracelet.

Our screenless wearable continuously tracks health, activity, sleep, recovery, and women’s health metrics while maintaining the appearance and comfort of a premium accessory.

The product combines embedded electronics, biometric sensors, ultra-low-power firmware, Bluetooth connectivity, mechanical components, interchangeable straps, and a mobile application that transforms health data into personalized insights.

We are expanding our engineering team in Monterrey and are looking for an experienced engineer who can contribute across embedded development, electronic hardware, product validation, and manufacturing.

The Role

As a Senior Hardware & Embedded Systems Engineer, you will help take Lumysi from advanced prototypes into reliable, scalable production.

This is not a firmware-only position. You will work across electronics, embedded software, supplier coordination, prototype development, product testing, and manufacturing execution.

You will collaborate directly with our internal engineering team, industrial designers, component suppliers, PCB manufacturers, assembly partners, and contract manufacturers.

The ideal candidate has previously worked with external manufacturing suppliers and understands what is required to move a connected hardware product from prototype through engineering validation, pilot production, and mass manufacturing.

Responsabilities

• Develop and maintain embedded firmware in C and C++.
• Work with Nordic Semiconductor and Espressif microcontrollers.
• Develop low-level drivers and integrate sensors and peripherals.
• Implement communication protocols including I2C, SPI, and UART.
• Optimize firmware for ultra-low-power operation and battery life.
• Work with Bluetooth Low Energy connectivity.
• Debug hardware and firmware integration issues.
• Support prototype testing, validation, and firmware releases.
• Collaborate with Miguel and external suppliers during prototype and production builds.
• Help investigate manufacturing issues related to electronics, firmware, testing, and device performance.
• Review technical documentation and communicate firmware requirements to manufacturing partners.

Requirements

• Degree in Electronics Engineering, Electrical Engineering, Mechatronics, Computer Engineering, or a related field.
• At least 4 years of experience in embedded firmware development.
• Strong programming experience in C and C++.
• Experience with low-level or bare-metal programming.
• Experience with Nordic and/or Espressif microcontrollers.
• Strong knowledge of I2C and embedded communication protocols.
• Experience with ultra-low-power or battery-powered devices.
• Ability to read electronic schematics and component datasheets.
• Experience debugging embedded systems using laboratory tools.
• Previous experience working with hardware suppliers, manufacturers, or contract manufacturers.
• Professional working proficiency in English.
• Availability to work in a hybrid model in Monterrey.

Nice to Have

• Experience with wearables, IoT, consumer electronics, or medical technology.
• Experience with Nordic nRF52 or nRF53 platforms.
• Experience with ESP32 platforms.
• Knowledge of FreeRTOS or Zephyr.
• Experience with PPG, motion, temperature, or biometric sensors.
• Experience supporting a product from prototype to production.

What We Offer

• Full-time hybrid position in Monterrey.
• The opportunity to build an international wearable technology product.
• Direct collaboration with the founders, engineering team, and manufacturing partners.
• Significant ownership over the firmware of the Lumysi wearable.