Charles Zhao.

Minebea Intec GmbH

Embedded Hardware Engineering Intern

For both my 2025 and 2026 internships, I signed my contracts directly with Minebea Intec GmbH, the company’s German headquarters. I was assigned to product development at the Chengdu office, which operates under the company’s China headquarters in Beijing.

Across my 2025 and 2026 internships, I designed and developed the original PR5170 and its variants, covering PCB hardware, embedded firmware, and desktop software.

• Designed standard-environment and Ex ec (gas Zone 2) variants of the digital communications mainboard, together with the Ex ec variant of the analog acquisition mainboard.
• Developed and integrated two Embedded C firmware branches on STC8/8051 controllers: CS5530-based analog acquisition with configurable filtering, and RS485 communication with an external digital weighing platform.
• Designed and developed TConfig using Electron, React, and TypeScript for multiple weighing instruments, including PR5170, supporting monitoring, parameter configuration, and calibration through RS232/SBI and RS485/Modbus RTU.
• Used instrument manuals, serial traces, and real-device feedback to correct command formats, data interpretation, and device-state handling across firmware and desktop workflows.

Across my 2025 and 2026 work periods at Minebea Intec, I designed or modified more than 20 PCBs.

Charles Tech

Embedded Systems Engineer & Owner

Operated an independent electronics design business serving international clients.

• Delivered schematic design and PCB layout services, including high-speed layouts and manufacturing-ready design files.
• Translated client requirements into board designs and established a repeatable engineering workflow from requirements through design and handoff.
• Shifted the business focus from client PCB services toward proprietary electronic product development.

Minebea Intec GmbH

PCB Designer

Designed and developed measurement, power, interface, and HMI hardware for the original PR5170 weighing instrument.

• Designed the standard-environment analog acquisition mainboard, covering load-cell signal conditioning, ADC and MCU circuitry, and RS232/RS485 communication.
• Designed the shared power and industrial-interface baseboard, integrating regulated supplies, connections for a company-purchased industrial Ethernet module, and an isolated 4–20 mA output.
• Developed HMI and protection-board variants for keypad/LCD interaction and hazardous-area configurations, including Zener-barrier, optocoupler, and isolated DC/DC circuitry.

Ningbo Chengzi Network Technology Co., Ltd

Website Developer

Contributed to WeChat product development, LLM workflows, and competitive research.

• Developed and launched a prototype WeChat Mini Program that attracted more than 100 early users in its first month.
• Refined prompts and context handling to improve LLM responses across different user scenarios.
• Analyzed more than 10 competing products and summarized findings to support product planning.