Fahad Zia Khan ~ Mediocre9

Backend Engineer

GitHub Blogs About

I am a fully focused backend engineer, but embedded and firmware development is a personal hobby that lets me explore how backend ideas translate into hardware constrained environments. Currently serving as a Lab Engineer at City University of Science and Information Technology.

Projects

VoyagerOTA

An OTA firmware distribution system for engineers

The VoyagerOTA backend service manages over-the-air (OTA) updates by providing a semantic versioning lifecycle. To ensure stability on embedded devices, the pipeline features validation steps ranging from binary build inspection to duplicate checking.

  • Enforces strict monotonic semver release controls.
  • Operates multi-stage release lifecycle phases (Draft, Staging, Production, and Revoked).
  • Utilizes background artifact inspection queue workers for build type mode validation.
  • Nginx for reverse proxying.
  • Caches release data with Redis to minimize response latency during device update pings.
VoyagerOTA Architecture
TypeScript Node.js Redis BullMQ MySQL NGINX
View Backend Repo

VoyagerOTA Client SDK

ESP32 C++ Embedded Library

Building upon the VoyagerOTA platform, this client SDK allows microcontrollers to communicate with external APIs and custom JSON endpoints. It provides logic for verifying release updates and fetching binary packages on embedded environments.

  • Native Semver comparison routines.
  • Supports alternate backends and GitHub releases via custom parser.
C++ ESP32
View Library Repo Published on Arduino Library Index

Multi Smart Locker System

Distributed ESP32 Firmware Design

Designed to work with distributed hardware, this firmware controls large physical relay grids via FreeRTOS scheduling. It connects to the backend and provides secure user access features without risking lock-state failures.

  • Controls up to 10 lockers per device
  • Low-level backend server dashboard for configuration, and user management
  • Firmware revocation checks via Firebase (background via Core Affinity)
  • Smart-Link mobile app integration (fingerprint + Gmail login)
  • Static API key-based access control
  • Remote OTA updates through VoyagerOTA platform
  • Per-locker auto-lock with WebSocket timeout updates
Locker Firmware System Flow
ESP32 FreeRTOS Firebase EspAsyncWebServer C++
View Firmware Repo

Smart Link App

Flutter App for Embedded & IoT Devices

The Smart Link app serves as the control center for smart lockers and robots. It integrates user authentication with hardware capabilities such as Bluetooth management and biometrics.

  • Integrates Google OAuth and account revocation services.
  • Handles fingerprint biometric authentication to securely issue locker unlocks.
  • Communicates via Bluetooth and Wi-Fi networks.
Smart Link Architecture Diagram
Flutter Firebase
View Mobile App Repo

Freelance Work

Integrated Google Gemini API in backend to perform LLM-based semantic evaluation of user responses against video subtitles using contextual prompts.

Gemini API LLM Backend

Collaborated with a freelancer friend to fulfill project requirements for their client. Experienced AWS ecosystem and integrated authentication using AWS Cognito Hosted UI. Tested and deployed frontend on AWS S3 via CloudFront for a UK Based Solar Energy Company.

AWS Cognito S3 CloudFront

Education

BSSE and MSCS (in progress)

  • IT & Robotics: Ex-President - Paid Intern
  • National HEC/PSEB IT Graduate Exam 2024: Passed with 84% Percentile