When activated, you can type a message in the computer's serial monitor. This message is then sent to the Arduino, which converts it into Morse code. The corresponding pulses are then shown by the blinking yellow LED, as well as a tone emanating from the speaker. The small potentio meter controls the pitch of the tone. Using the push button, a user can manually pulse the Arduino.

Arduino sketch

Demonstration (MP4, 14.8 MiB)

Electrical diagram:

Assembled and soldered protoshield: