Development of a Compact Hardware-in-the-Loop Platform

I collected and structured the validation requirements for the company's three target VCUs. This included signal types, channel counts, voltage and current levels, PWM capabilities, communication interfaces, power supply requirements, physical constraints, and future extension needs.

I then created a high-level system diagram in draw.io showing the processing architecture and all required driver blocks, with the requirements for each block documented directly in the diagram.

I selected the main components based on the required digital and analog signal channels and their performance requirements, as well as the necessary PWM, timer and communication interfaces, processing performance, electrical specifications, availability, and cost.

A dual-STM32F407ZGT7 architecture was selected because one microcontroller did not provide enough pins, timers, and peripheral resources for the complete system. I selected the principal interface drivers, fixed the first detailed architecture, and prepared a preliminary BOM estimate to verify the cost direction.

I created the first complete schematic in Altium Designer using the selected microcontrollers, interface drivers, and communication components. Placeholder passive components were initially used around the main drivers so the circuit architecture could be defined before every value and reference was fixed.

I used hierarchical sheets, repeated functional blocks, multi-channel structures, harnesses, buses, reusable circuits, and centralized component-parameter management. I then sized and selected the remaining filters, protection devices, resistors, capacitors, connectors, and supporting components for the complete project.

I developed the BOM in parallel with the schematic using Altium ActiveBOM. Each schematic update was reflected in the cost and sourcing view, allowing me to monitor supplier references, component availability, alternatives, missing parameters, individual component prices, and the resulting total hardware cost.

This continuous process reduces the risk of discovering expensive or unavailable components after the schematic is complete. The BOM remains preliminary and will be finalized after the ongoing circuit validation.

I translated the system architecture into dedicated functional prototypes, independently designing the schematics, PCB layouts, and 3D assemblies in Altium Designer. Each prototype was produced to de-risk a representative part of the final HiL platform and to validate the design before full-system integration.

I assembled and soldered the prototype hardware myself, then used an STM32F407G-DISC1 evaluation board as the microcontroller platform for bring-up and functional testing. For every prototype function, I wrote and executed a test plan covering the intended electrical behaviour, firmware interaction, and measurable acceptance criteria.

Through this work, most of the platform’s core functions have been prototyped and fully validated, including digital and analog I/O behaviour, PWM generation and measurement, timing performance, GPIO operation, and peripheral interfaces. The remaining work focuses on integrating the validated functions into the complete HiL platform and verifying their operation together.