I'm Ierotheos Katsoulis — an electrical & electronics engineer designing embedded systems, IoT hardware, and machine-to-machine protocols. From custom PCBs and vehicle diagnostics to voice assistants on Raspberry Pi, I take projects from schematic to working product.
I've spent the last several years at the intersection of hardware and software — designing PCBs, writing firmware for STM32 and ESP32, building CAN/J1939 diagnostic systems for vehicles, and deploying ML on edge devices.
Alongside freelance work I'm a service engineer at Divitec S.A., and I've taught Optoelectronics and Quantum Mechanics at the University of West Attica, where I also contributed to published research in refractometry of attenuating media.
If your problem involves a microcontroller, a sensor, a bus protocol, or anything between bare metal and the cloud — let's talk.
A custom-designed scoring board built end-to-end for a sports equipment manufacturer. Schematic capture, PCB layout, SMD assembly, microscope-assisted rework, 3D-printed enclosure, and final integration — every step done in-house.
Isn't life really the ultimate game? Coming soon on Android.
End-to-end diagnostic system for heavy vehicles: hardware interface, J1939 frame decoding, remote control logic, and a data pipeline for real-time fleet monitoring.
Local-and-cloud hybrid voice assistant running on Raspberry Pi. Optimized voice pipeline (VAD → ASR → intent) and LLM orchestration with privacy-respecting on-device fallback.
Deployed OpenCV-based facial expression recognition on low-power embedded devices. Tuned the pipeline for real-time inference under tight memory and CPU budgets.
Designed audio amplifiers and guitar footswitches from schematic to PCB. Also handle repair and electronic debugging of existing audio hardware.
Optical characterization of materials using refractometry and photometric techniques. Measurement system design, data acquisition, and statistical error analysis for peer-reviewed research.
Built blockchain-integrated frontends with wallet authentication flows and clean interfaces for on-chain data — making complex contract interactions feel like a normal web app.
Web apps with user authentication, payment integration, and database-driven backends — from client dashboards and SaaS tools to niche products like a pet health tracker with profiles, scheduling, and alerts.
Pixel art idle RPG built from scratch for Android. Infinite exponential scaling, 6-skill combat system, equipment gacha with grade combining, EXP/level progression, and JSON save/load — all in a portrait mobile layout.
Laptop and phone repair down to board level, plus data retrieval from damaged or non-booting devices.
From peer-reviewed research and full product builds to a board that just needs fresh eyes — no job too complex, no fix too small.