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Senior Software Architect specializing in secure systems and IoT Sec solutions with 15+ years of experience. I architect and deliver end-to-end nfc solutions, from embedded firmware to cloud-based backend systems. 🎯 CORE EXPERTISE IOT Systems - NFC Solutions: Reader/Writer, HCE, Digital Wallets (Android/iOS) - Smart Cards: JavaCard, MIFARE, DESFire, NTAG,Global Platform,GP,JCOP,Secure Element - Security: PKI, FIDO, Secure Element,HSM, PCI-DSS Compliance - RFID Systems: Asset Tracking, Access Control - EMV Payment: L1/L2/L3 Kernel Development & Certification - Microcontrollers: ESP32, STM32 (WiFi/BLE, RTOS) - Firmware: Secure Bootloader, OTA Updates, Real-time Systems - Industrial Applications: POS Terminals, Vending Machines, Access Control - IoT Architecture: Sensor Integration, Remote Management Full-Stack Development - Backend: Node.js, REST APIs, Database Design (SQL/NoSQL) - Cloud Services: Firebase, AWS/Azure/GCP Deployment - Mobile: Android (NFC APIs), iOS (CoreNFC), React Native - Desktop: Qt, .NET, Cross-platform Applications - Languages: C/C++, JavaScript/TypeScript, Java, C# 💼 SIGNATURE PROJECTS ✅ ESP32 IoT Systems - Created NFC-enabled payment solution with cloud integration - Built secure firmware with OTA update capabilities - Integrated Firebase for real-time data synchronization ✅ Cross-Platform Digital Wallet - Developed mobile wallet supporting EMV contactless payments - Implemented HCE and Secure Element integration - Built Node.js backend with Firebase authentication ✅ Enterprise RFID Solutions - Designed asset tracking systems for industrial clients - Implemented access control with NFC/RFID readers - Deployed cloud-based management platform ✅ EMV Payment Terminal Solutions - Developed EMV L2 & L3 kernel for contact/contactless terminals - Achieved EMVCo certification for payment applications - Implemented secure key management and transaction processing 🔧 TECHNICAL STACK Hardware: ESP32, STM32, NFC Readers, RFID Systems Backend: Node.js, Express, Firebase, REST APIs Database: MongoDB, PostgreSQL, MySQL, Firestore Cloud: Firebase, AWS, Azure, Docker deployment Mobile: Android, iOS, React Native Desktop: Qt, .NET, Windows/Linux Security: PKI, FIDO, PCI-DSS, Secure Boot 📋 CERTIFICATIONS & STANDARDS EMVCo, PCI-DSS, PBOC, Global Platform, ISO 14443 I deliver production-ready solutions with clean code, comprehensive documentation, and ongoing support. Available for both fixed-price projects and long-term contracts.

Full Stack & IoT Developer | Kiosk Systems | Mobile Apps | Embedded Solutions I help businesses turn ideas into complete, production-ready products. Instead of hiring separate developers for mobile apps, backend systems, and embedded devices, I provide end-to-end development covering everything from hardware integration to cloud services. Over the past 5+ years, I have built commercial software, IoT products, business systems, kiosk applications, and connected device solutions for startups, companies, and organizations. What I Deliver • Kiosk & Tablet Solutions * Customer feedback systems * Self-service kiosks * Visitor management systems * Android tablet applications * Offline-first business applications * Device management interfaces • Mobile & Cross-Platform Applications * Android and iOS applications * Desktop applications * Internal business tools * Modern, responsive user interfaces • Backend & Cloud Systems * REST APIs * Authentication systems * Admin dashboards * Reporting and analytics * Third-party integrations • IoT & Embedded Development * ESP32 and STM32 firmware * BLE, WiFi, MQTT, LoRaWAN * Serial Port communication * Sensor integration * Hardware-to-cloud connectivity Why Clients Work With Me • One developer responsible for the entire solution • Faster development with fewer communication gaps • Strong understanding of both software and hardware • Clean, maintainable, production-ready code • Transparent communication and reliable delivery Typical projects I work on include kiosk systems, tablet applications, IoT products, industrial monitoring solutions, connected devices, internal business tools, and custom software platforms. Whether you need a prototype, an MVP, or a complete product ready for deployment, I can help transform requirements into a reliable working solution.

I’m Simon, Heading the IoT Systems architecture at Maxlinktek (US), supported with my own high-performance R&D team in China. [Verified Profile Summary by Upwork AI System Engine]: “ An experienced IoT solution architect specializing in full-stack hardware and software integration for scalable ecosystems. Demonstrated expertise in PCBA design for IoT products, including HVAC controllers [1] and low-power wearable devices [2], along with comprehensive hardware cost assessments [3]. Skilled in systems architecture, BOM optimization, and regulatory compliance, applying these skills to enhance production efficiency and device functionality. Proven track record in transitioning projects from prototypes to successful mass production. Generated by Uma, Upwork’s Mindful AI, from completed jobs ” Skills: ● Systems/Product architecture. ● PCBA design (Altium/KiCad) ● Linux Kernel/APP development(C/C++) ● STM8/STM32/ESP32/CH59x BLE/Other MCUs development(C/C++) ● PHP Laravel + Swoole(server backend) ● VUE UI(HTML5/Javascript) ● Android/iOS APP development(Flutter/Electron) ● DFM (Design for Manufacturing): Optimization for high-yield assembly and die-casting to minimize defects. ● Mass Production (MP) Management: Experienced in overseeing the lifecycle from EVT/DVT/PVT to full-scale production. ● BOM Optimization: Strategic sourcing and component selection for supply chain resilience and cost-efficiency. ● Regulatory Compliance: Pre-scan and verification for international standards (UL, CE, FCC, IP67/68). I bridge the gap between US-standard strategic leadership and direct Shenzhen factory-floor execution.With 15+ years in Linux development & maintenance and 8+ years in professional PCBA engineering, I specialize in building production-ready IoT ecosystems — from the first circuit trace to global mass production. This setup allows me to provide US-standard communication and project management, combined with unmatched cost-efficiency and R&D speed through my dedicated team in China. FROM PROTOTYPE TO MASS PRODUCTION 🚀 WE BUILD SCALABLE IOT ECOSYSTEMS — NOT JUST DEMOS. Most IoT projects fail after the prototype stage. We bridge the gap between a "bench-top demo" and a global product launch.. 💡 WHY PARTNER WITH US? ● 30%-75% Hardware Cost Reduction: We replace bloated Android setups with high-performance Native ARM Linux. This achieves fluid UI/UX with lower hardware requirements and bedrock system stability. ● 20%-40% BOM Optimization: Leveraging deep Pearl River Delta supply chain expertise, we proactively suggest reliable chip alternatives to maximize your profit margins and secure components against global shortages. ● Zero-Gap Delivery: We perform deep on-site debugging and automated firmware flashing in China. You receive fully functional, validated hardware units—not bare, untested boards. 📦 PROVEN TRACK RECORD Due to strict NDA obligations with enterprise clients, only a selected portion of our portfolio is showcased below: ● LG DUOBO Coffee Machine: End-to-end integration (PCBA, Firmware, App). ● Nscreen32: World’s first LVGL-certified development board. ● Ntablet: Highly successful open-source hardware tablet framework. 🤝 WHO WE WORK WITH We partner with serious IoT startups and enterprise teams who view their hardware as a long-term venture. If you want to build a real, scalable product—not just a bench-top demo—we design for mass production from day one. 👉 Send an invite with a short description of your project, and I will suggest a high-level system architecture for your review.

👋 Hello, I am YanXia Xu. Embedded Systems Engineer with nearly 30 years of experience in industrial automation and embedded firmware development. Specialized in MCU firmware, RTOS-based systems, industrial communication protocols, and embedded Linux platforms. Extensive experience supporting Japanese enterprise projects and long-term industrial product maintenance. Strong background in debugging, hardware-software integration, and reliable embedded system design.

Thank you for taking the time to view my profile. I'm a professional electrical engineer with experience in power electronics, digital circuits, analog circuits, and HF RF circuits. My favorite EDA tools are OrCAD or KiCad for schematics capture, Allegro or KiCad for PCB layout, LTspice for analog circuit simulation, Verilog/SystemVerilog/Vivado/ModelSim/Questa for digital and FPGA design, SIMetrix/SIMPLIS for SMPS design, dsPIC33/MPLAB/PowerSmart for digital power design. Still, I have used many other EDA tools under customer/client requests in the past, such as Pspice, TINA-TI, ADS, Quartus Prime, etc. I'm also a professional programmer with experience in PC BIOS, BSP, Linux, and Android, and I'm familiar with many programming languages such as x86 assembly, ARM assembly, C, C++, Java, Python, HTML, CSS, XML, SQL, JavaScript, Unix shell script. I have many mass production designs for domestic clients and some from foreign countries. If you want reference to some of my product designs, I can ask for the client's permission as they are mostly NDA secured. I'm serious about the intellectual properties of others. But you can view my portfolio for a LF N2PK VNA and a Red Pitaya STEMlab125 designs, both are the few best in class amateur measurement equipment with professional device quality, I improved on their original design to better fit my daily electrical test requirements, and as I just produce my own improved design for my private use, so it's legal for me to show them here without IP issues with the copyright holders. My current interest and most recent skills are FPGA, SMPS, digital power, motor control, and automotive electronics.

I’m a Full-Stack Embedded Engineer specializing in MCU-based hardware and firmware design. From circuit schematics and PCB layout to firmware development, debugging, and production support — I deliver reliable, manufacturable embedded systems. ⚙️ What I Do 🔹 Embedded Hardware Design MCU-based circuit design (STM32, ESP32, Arduino, etc.) PCB layout for compact, power-efficient, and production-ready boards Power supply design, analog/digital signal routing, EMC/EMI consideration Prototype validation and debugging with oscilloscopes, logic analyzers 🔹 Embedded Firmware Development Bare-metal and RTOS firmware (FreeRTOS, ESP-IDF, STM32 HAL, Arduino) Communication interfaces: UART, I2C, SPI, CAN, BLE, Wi-Fi Sensor and actuator integration (ADC/DAC, PWM, GPIO, I/O expansion) Bootloader, OTA update, and low-power optimization 🔹 System Integration & Debugging Hardware-software co-design and joint debugging Interface communication validation and timing optimization Peripheral driver tuning and performance profiling 🔹 Production & Manufacturing Support DFM/DFA optimization for stable mass production BOM cost-down and alternative component sourcing Coordination with PCB and assembly vendors Prototype-to-production transition and testing support 🎓 Background Master’s degree in Electrical Engineering 5+ years of hands-on experience with MCU-based embedded systems Projects across IoT devices, industrial controllers, consumer electronics, and medical prototypes 🚀 What You Get ✅ Custom schematics + PCB layout for MCU systems ✅ Firmware development + hardware integration ✅ Prototype debugging and functional testing ✅ DFM optimization + production coordination ✅ Full documentation and support to manufacturing Whether you need a custom MCU board, firmware integration, or help turning your prototype into a manufacturable product, I’ll make sure your system runs efficiently, reliably, and ready for production. 💬 Let’s discuss your project and make it real!