Anthony Marsico's Modernized Take on the Telegraph Turns Morse Code into MQTT Messages
Espressif ESP32-powered Wi-Fi telegraph can transmit clear across the world, thanks to the wonder of the internet.
Maker and ninth-grade student Anthony Marsico is looking to update the classic telegraph — by building a 3D-printed, internet-connected version that can transmit messages via MQTT.
"The telegraph was a groundbreaking invention in the 1840s. It was one of the first inventions of its time that allowed near instant, long distance communication. This was a major milestone in communication because before the telegraph messages had to be physically carried by messengers on horseback or by ships. This would take anywhere from days to weeks depending on where the message was going. Its use sadly declined and became obsolete in the early 1900s due to the increasing popularity of other communication inventions."
Marsico's take on the telegraph features the same kind of Morse key you'd find on an original, but in a wholly 3D-printed housing — sitting on a desk, rather than taking up most of it. Rather than a printer there's a small OLED panel where messages can be viewed as they're entered, and a key to transmit them once you're finished. Single-key message entry is achieved, of course, via Morse code, with a built-in lookup table converting your dashes and dots to ASCII text on-the-fly.
Messages entered into the telegraph are transmitted via radio, just like the original — but via Wi-Fi. Unlike the original devices, though, this modernized system works via MQTT: your entered text is encoded as an MQTT message and sent to a broker, with other telegraph users able to subscribe to the broker to receive and reply. "It only works with Wi-Fi because I wanted to create a telegraph that can work from across states and even countries," Marsico explains. "Other forms of communication with an ESP-32 would only go anywhere from a couple hundred feet to about a mile. Also most of these methods would be less effective at communication in a city due to big buildings and obstacles not offering a clear signal to the other telegraph."
The project is documented in full on Instructables, with STL files for the 3D-printed housing and source code under an unspecified license.