Four switch input to make any button controlled Application.
Buzzer connected with Arduino nano for any kind of alerting.
ULN2803 Line driving IC having 8 free inputs any GPIO of Arduino nano can connect with ULN2803 input to drive any device like Relay, LED, and Motor etc.
8 LED connected with output of ULN2803.
Relay to drive any AC device through Arduino Nano
Power Section
DC 12V input socket. Further 12 V converted to 5V using switching regulator LM2576.