Build a working telegraph between two rooms

How to do it

Set up: a 9V battery in series with a push-button (the 'key'), connected by 25 feet of wire to a 9V buzzer (the 'sounder') in the other room. Press the button → buzzer sounds. Run a second wire back so the receiver can reply. Print a Morse code table. They send 'HI' (.... ..). You send 'HI' back. Now they spell their name. By the end of an hour they know SOS, their name, and 'come here'. The wire is the thing. Telegraphs ran the world for 100 years on this exact principle.

What you'll need

• 9V piezo buzzer (2-pack)

  Amazon

• 25 ft thin gauge wire spool

  Amazon

• Push-button switches (large)

  Amazon

• 9V battery + clip

  Amazon

• Morse code printable

  PrintableOpen