Design of a GSM-Controlled Home Automation System for Energy Management in Lagos Residential Areas

Rising electricity tariffs and erratic power supply in Lagos, South West Nigeria, have increased the urgency for affordable home energy management systems that allow homeowners to monitor and control appliances remotely. This project designed a GSM-controlled home automation system that enables remote switching and monitoring of up to eight household appliances via SMS commands from any mobile phone, without requiring internet connectivity. An Arduino Mega 2560 microcontroller interfaced with a SIM800L GSM module managed relay-based switching of appliances classified across lighting, air conditioning, and high-wattage load categories. The system used current transformers (ACS712) to measure real-time power consumption of each channel and logged daily energy usage in kilowatt-hours to EEPROM for weekly reporting via SMS. A password-protected command structure prevented unauthorised control. The system was bench-tested across 500 simulated SMS control cycles. Command recognition accuracy was 100 percent for correctly formatted SMS commands. SMS response time averaged 6.8 seconds. Current measurement error was within plus or minus 3 percent compared to a calibrated clamp meter reference. System average standby power draw was 1.8W. The estimated monthly energy savings through automated load scheduling were projected at 18 to 24 percent of baseline consumption in a typical three-bedroom Lagos household. The study recommends replacing the SMS-only interface with a WhatsApp Business API integration as a user experience improvement, given WhatsApp's widespread adoption among Lagos residential users.

Keywords: home automation, GSM control, energy management, Lagos, microcontroller