Smart Automation for Residential Spaces with PLC-ESP32 Architecture

This paper presents the design, development, and testing of a smart home automation system that integrates a Siemens LOGO! programmable logic controller (PLC) with an ESP32 microcontroller to enable dual-mode control—manual and voice-activated. The system automates essential home functions such as lighting, irrigation, gate control, and ventilation. Through the use of the fauxmoESP library, the ESP32 communicates with Amazon Alexa, converting voice commands into GPIO signals interpreted by the PLC. Manual control is retained via pushbuttons, ensuring operational redundancy in case of network or hardware failure. The system architecture includes optocouplers and relays to ensure voltage compatibility and device protection between the 3.3 V microcontroller and the 12–24 V PLC inputs. Functional tests revealed a 100% success rate in manual operations and over 95% in voice-controlled actions, with notable differences in response times. A cost breakdown and risk analysis are also included to assess feasibility and sustainability. This prototype highlights a practical, low-cost solution for residential automation, with scalability potential for broader smart home applications and educational or industrial implementations.