Reverse Engineering the Duco Connectivity Board: Home Assistant Integration Achieved

Frustrated with the limited control options of his DucoBox ventilation system (only four modes via a simple button), the author decided to reverse engineer the official, expensive Duco Connectivity Board, which is essentially an ESP32. Using a logic analyzer and information from Duco's website, the author analyzed the communication protocol between the board and the ventilation system. It turned out not to be Modbus, but a custom protocol. After decoding the protocol, the author created an ESPhome component, enabling seamless integration with Home Assistant. This significantly enhances control and allows for reading CO2 sensor data and other information.