Embedded Hardware / IoT Engineer (ESP32 Product Development)

Job Description

ReceiptRoller Inc. builds an electronic receipt platform working toward a world without paper receipts. To realize that vision on the hardware side — and to drive the range of IoT products we plan to release — we're looking for an embedded hardware / IoT engineer.

You'll own IoT devices end to end, from prototyping through to production-ready design, built around microcontrollers like the ESP32. That spans wireless communication (Wi-Fi/Bluetooth), sensor control, and mechatronics — firmware, circuit design, and hands-on bring-up all in the same role.

This is a fully remote position; we provide the development boards, instruments, and prototyping equipment you need to work from your own bench. If you enjoy moving between a datasheet, a soldering iron, and a code editor without worrying about which side of the hardware/software line you're on, this is the kind of work we have.

Responsibilities

- Embedded firmware development for IoT devices — C/C++ control programs on ESP32 (ESP-IDF, Arduino) and STM32-class MCUs
- Wireless protocol implementation (Wi-Fi / Bluetooth / NFC) and cloud integration
- PCB design, prototyping, and evaluation — schematic capture and board layout using circuit CAD (KiCad, Eagle)
- Power circuit design (lithium-ion, USB, AC/DC) and motor / sensor drive circuits
- Rapid bring-up and validation on universal boards, breadboards, and FPC/FFC adapters, including hand soldering
- Signal, current draw, and thermal evaluation with an oscilloscope, and designing the fixes
- Mechatronics control — stepper motors, servos, and actuators; excitation and drive
- Sensor monitoring and control (paper detection, cover, temperature, acceleration, etc.)
- Interface integration with main systems and main boards (Serial DB9 / USB / Ethernet / I2C / SPI / UART)
- Design for volume production of compact IoT devices and POS-adjacent terminals

Requirements

- Professional experience developing embedded firmware in C/C++ on MCUs such as ESP32 or STM32
- Experience designing PCBs with circuit CAD — both schematic design and board layout
- Working knowledge of wireless communication (Wi-Fi, Bluetooth/BLE), sensor control, and mechatronics drive circuits
- Hardware debugging and waveform measurement experience using an oscilloscope or logic analyzer
- Ability to read datasheets accurately (English or Japanese) and implement from pin assignments and timing charts

Preferred Skills

- Precision board design and assembly experience with FPC / FFC connectors
- Cloud integration for ESP32-based IoT products (AWS/GCP) and MQTT/HTTP implementation
- Experience taking compact IoT devices, POS-adjacent terminals, or electronics prototypes to volume production
- Knowledge of battery/power circuit optimization and EMC countermeasures
- Experience collaborating closely with enclosure designers using 3D CAD (Fusion 360 or similar)

Languages

Japanese, English