Freelancer profile translated to English.
Back to original languageAbout Tsz Shun
Experienced Senior Embedded Software Engineer and System Architect with a focus on IoT, telecommunications, and real-time systems.
I am the owner and lead developer of a Qt-based dispatcher software, used as a central control and communication platform for distributed push-to-talk and IoT devices. The system includes desktop applications, embedded devices, network protocols, and server-side components.
My technical focus is on Qt/C++, Embedded Linux, microcontrollers (STM32, ESP32), and secure real-time audio solutions (SIP/RTP, Opus, end-to-end encryption). I regularly work on systems with limited resources, high reliability requirements, and low latency.
Additionally, I have practical experience with the LAMP stack (Linux, Apache, MySQL, PHP) for developing backend services, admin tools, and internal management systems, particularly for supporting embedded and IoT platforms.
As a freelancer, I take responsibility for the entire development cycle – from architectural and technology decisions through implementation to stabilization, maintenance, and handover to production.
English
Native or bilingual
German
Conversational
Kantonesisch
Native or bilingual
Chinese
Native or bilingual
Can work on-site
Trier (up to 50km)
Experience
- Tramigo OyChief System ArchitectAugust 2024 - Today (1 year and 10 months)Responsible for the system architecture and overall technical coordination of several hardware and software projects in the area of push-to-talk and IoT communication.Owner and principal architect of the Qt-based dispatcher software (v2.0), including complete technical redesign, modernization of the codebase, and long-term maintenance strategy.Led and coordinated two hardware projects:Embedded Linux device (system design, software stack, update strategy, integration of cellular modems)RTOS-based embedded device, focusing on architectural alignment, task distribution, and system integrationTechnical responsibility for the integration of embedded devices, desktop applications, and backend systems into a stable, production-ready platform.Additionally, designed and implemented a replay and analysis tool based on ReactJS and Material UI for visualization and evaluation of communication and device data.Close collaboration with product management, hardware partners, and international development teams to ensure scalability, maintainability, and technical quality.
- Wiress Technologies FinlandSoftware DeveloperTELECOMMUNICATIONSFebruary 2020 - Today (6 years and 4 months)Espoo, FinlandLong-term involvement in the development, further development, and maintenance of a Qt-based desktop dispatcher software for professional push-to-talk and communication systems.Participation in the entire system lifecycle – from proof-of-concept phases and functional enhancements to stable production releases, with increasing responsibility for technical decisions and system understanding.In-depth work in real-time audio processing, including:Integration and optimization of Opus audio codecs (libopus)Development of audio packaging and streaming logic based on RTPAnalysis and debugging of SIP and RTP streams (INVITE, ACK, BYE) using WiresharkImplementation of end-to-end audio encryption with libsodium, focusing on security, performance, and reliability in real-time communication environments.Development and maintenance of the Qt application architecture, including:Modular UI structuresCustomer-specific adaptation of branding and layoutUse of the Qt Installer Framework for regular updates and rolloutsImplementation of additional functional modules such as GPS tracking and geofencing (Leaflet-based map integration).Support for adjacent platforms and tools, including:Automation of build and deployment processes (Golang scripts)Android app development with Kotlin to extend and integrate mobile functionsFrontend components with ReactJS and Material UI for complementary web tools
- volatiles lighting GmbHEmbedded DeveloperINTERNET OF THINGS (IOT)June 2018 - August 2019 (1 year and 3 months)Berlin, GermanyDeveloped firmware for STM32 Cortex M4 applications in FreeRTOS, using DaisyChain configuration for enhanced connectivity.Designed and implemented GUI tools with Python and PyQT to streamline workflows.Developed a custom file format for converting JPEG-compressed videos to improve compatibility with our product.Engineered drivers in C with a focus on performance optimization and system integration.Integrated external services into our product using MQTT to enhance functionality and interoperability.
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Education
- Electrical EngineeringThe Hong Kong Polytechnic University2017
Certifications
- Linux System Programming and Introduction to BuildrootUniversity of Colorado Boulder2024