Arduino is a microcontroller board based on the ATmega328P (datasheet). It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP header, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started.
You can use an Arduino to control your home automation system. You can use it to control lights, fans, and other devices. You can also use it to control your home automation system using MQTT.
The Arduino language is based on Wiring, which is based on Processing. The Arduino language is a subset of C/C++. It is very easy to learn, and it is very easy to use. Most of the time, when you are programming an Arduino, you will be using the Arduino language.