This Wi-Fi-Connected Graduation Cap Displays Custom Messages

It is early June, which means we have a whole bunch of recent graduates that just took their walks across the stage to get their diplomas. The traditional graduation cap and gown ensure uniformity, but that keeps graduates from expressing their individuality. As such, many graduates decorate the tops of their caps with personal art and messages. Andrew Goldberg wasn't satisfied with a few glued-on letters from Michael's, so he constructed a Wi-Fi-connected display to attach to his graduation cap and show custom messages.

Goldberg just graduated high school and will be heading off to UC Berkeley for college in the fall, so naturally his cap got decoration representing the university (like Oski the Bear). But he wanted some extra flair, which is where the display came in. It sits atop the cap and shows messages on an 8x32 LED matrix. It hosts its own web interface that users can reach by connecting to the Wi-Fi access point. The interface lets users enter strings of text, which will then start scrolling across the LED matrix.

An ESP32 development board controls the LED matrix, which has a standard MAX7219 driver. Power comes from a small USB battery pack like you'd use to top off your smartphone. Those components fit inside a custom 3D-printed enclosure that Goldberg designed in Autodesk Fusion 360. The enclosure attaches to the cap with double-sided tape and velcro. Goldberg also 3D-printed some additional decoration for the cap, like stars and the number "23" for his graduation year.

Goldberg's code for the ESP32 lets the owner set a password for the access point, but it is also possible to leave it open and unsecured if the owner is brave enough to allow strangers to set messages.