If you want to add a display to your Arduino project, the easiest solution will likely be an LCD or OLED screen. But though those are affordable and work really well, they may not provide the vibe you’re looking for. If you want a more vintage look, Vaclav Krejci has a great tutorial that will walk you through using old-school LED bubble displays with your Arduino.

Krejci’s video demonstrates how to use HPDL-1414 displays, which are what most people call “bubble” displays, because they have clear bubble-like lenses over each character’s array of LEDs. They were fairly popular in the late ‘70s and ‘80s on certain devices, like calculators. These specific bubble displays can show the full range of alphanumeric characters (uppercase only), plus a handful of punctuation marks and special symbols.

The HPDL-1414 displays Krejci used come on driver boards that set the characters based on serial input. In the video, Krejci first connects those directly to a PC via a serial-to-USB adapter board. That helps to illustrate the control method through manual byte transmission.

Then Krejci gets to the good stuff: connecting the HPDL-1414 bubble displays to an Arduino. He used an Arduino UNO Rev3, but the same setup should work with any Arduino board. As you may have guessed based on the PC demonstration, the Arduino controls the display via Serial.print() commands. The hex code for each character matches the standard ASCII table, which is pretty handy. That makes it possible to Serial.write() those hex codes and even Serial.write() the actual characters.

Don’t worry if that sounds a little intimidating, because Krejci has sample code that will let you easily turn any arbitrary array of characters into the serial output you need. Now you can use those awesome bubble displays in your own projects!