A variation of the blinking LED exercise using Arduino Nano and an on-board LED.
The serial monitor asks the user for a message. The message can contain letters from A to Z and numbers from 0 to 9. If the message contains other characters, the monitor responds and asks for a new message.
The LED blinks the message in Morse code while the serial monitor prints out the Morse code in dots and dashes. When it's done, the programme loops back and asks the user for a new message.
Open the morse-code.ino file in Arduino IDE, connect the Arduino Nano board with the set-up shown below, and click "upload".