Smart Home Solution

The Smart Home Solution is an IoT-based automation and surveillance system built around the NodeMCU ESP8266 microcontroller board. At the core of the circuit, the NodeMCU connects to a local Wi-Fi network, allowing it to communicate over the internet using the MQTT protocol handled by the PubSubClient library. Users interact with the system primarily through an Android smartphone application developed using Android Studio and Java 8, which sends and receives commands and status updates. When a voice command or remote button press is triggered on the mobile app, it publishes a message to the MQTT broker hosted on a Google Cloud VM running JavaScript, or utilizes AI speech processing frameworks such as Google Colab. The ESP8266 subscribes to these MQTT topics, parsing the incoming payloads to execute actions. To control physical loads, the microcontroller's digital output pins trigger a relay module. The relay acts as an electrically isolated electronic switch capable of opening or closing higher-current circuits for connected home appliances. Simultaneously, environmental monitoring is achieved via the DHT temperature and humidity sensor connected to the NodeMCU, which reads ambient data using the Adafruit DHT library and transmits these metrics back to the cloud and the Android interface. Jumper wires establish the necessary power, ground, and signal connections between the NodeMCU, the relay, and the DHT sensor, while a standard USB cable provides programming and initial power delivery during development.