An ESP32 Controls This Cylindrical OLED Display

The vast majority of displays have a rectangular 16:9 aspect ratio, or 4:3 for older TVs and monitors. But we're starting to see more unusual aspect ratios and even screen shapes become more common. Some newer smartphones have ultra-widescreen aspect ratios and round displays are the norm for smartwatches. A square may be the most efficient form, because it doesn't waste any rows or columns in the matrix, but people like more unique shapes. YouTuber maker.moekoe took that idea to the extreme when they built this ESP32-controlled cylindrical screen.

"Cylindrical" is a bit of a lie, because this device actually has eight flat 4:3 OLED screens arranged around the perimeter of an octangular enclosure. But the effect is that of a cylindrical display. Messages scroll from one screen to the next, sliding across the full 360 degrees. We're not quite sure what the practical use case for this device would be, but it sure looks cool. Each screen is quite small at 0.96", so this wouldn't work for a central display in a public area. Nevertheless, it is fun to watch in action and should provide some inspiration for our more creative readers.

Most devices only have a single screen, so driving eight screens simultaneously isn't a trivial undertaking. An ESP32 microcontroller is the brains of the operation. Details aren't available, but it is safe to assume that it controls the OLED screens via SPI. A single microcontroller can handle several SPI devices as long as they each have their own chip select (CS) pin. maker.moekoe designed a custom octangular PCB to simplify the wiring, including the ribbon cables for the screens.. In addition to the OLED SPI connections, that also has chips to handle the power management for a LiPo battery and a USB-C plug for charging. The PCB and OLED screens fit inside of a custom 3D-printed case.

Because maker.moekoe used an ESP32 with built-in WiFi and Bluetooth connectivity, he can update the scrolling messages through his smartphone. He can enter text in a custom Blynk app, along with the desired number of loops, and that information gets sent to the ESP32 over WiFi through the Blynk IoT service. While we don't know what purpose this device serves, there is no denying that the form factor is more interesting than another boring ol' rectangle.