So begins Tim Jacobs’ explanation of his brilliant volumetric display. It’s a tiny build (pictured here with a human finger for scale), and it’s also quite brilliant in its approach to an engineering challenge: the problem that you normally get when building anything using persistence of vision is getting power to the moving parts. If you have an LED mounted on something spinning, you need some way of getting power to the LEDs without getting the power wires twisted up. You can do this using wireless power, or by using brushes that maintain contact even as they spin, but that naturally increases complexity, cost, and the likelihood that the device will fail at some point. Tim got round this challenge by making everything spin. The display, the electronics, the motor, even the battery all rotate when the motor is running. Problem solved!

So far, Tim’s used his display to show fluid sloshing about in a container, a spinning cube, and a candle flame among others. Naturally, you don’t appreciate the full glory of the animations when you’re looking at a static image, but while we’re here, we can all coo over the free-form soldering that he’s used to attach the display to the Waveshare RP2040-Tiny, a small board that breaks out some of the GPIO pins from Raspberry Pi’s RP2040 chip.