Mini-HVAC IoT System
ESP32 + Simulink Hardware-in-the-Loop Platform
A hardware-in-the-loop mini-HVAC platform built as the capstone project for Sistemas Digitales Programables at UCAM (Universidad Católica de Murcia). The system pairs a five-subsystem Simulink plant model with an ESP32-WROVER running custom FreeRTOS firmware, enabling closed-loop thermal control where the simulated plant and the physical controller exchange data in real time over a binary serial protocol.
The serial interface is built around compact packed structs — a 24-byte PcToEsp command frame and a 32-byte EspToPc telemetry frame — validated byte-by-byte with MATLAB scripts and enforced at compile time via static_assert size checks, ensuring wire-format consistency between the C firmware and the MATLAB/Simulink host.
The FreeRTOS firmware is organized into three cooperative tasks: TaskTX transmits sensor readings and controller state at a fixed cadence, TaskRX parses incoming plant commands and updates setpoints, and TaskLCD drives the I²C display. All three tasks share state through a mutex-protected global struct, keeping synchronization simple and deterministic.
The physical platform is mounted on a custom wooden board and includes a DHT22 temperature/humidity sensor, a PWM-controlled fan, a 16×2 I²C LCD, potentiometers for manual setpoint adjustment, and debounced pushbuttons for mode selection.
The project is accompanied by 11-chapter ReadTheDocs-style documentation written entirely in English, covering everything from plant modeling and controller design to the serial protocol specification and macOS development environment setup.
