Don’t get us wrong — we love unique displays as much as anyone. But sometimes we stumble across one that’s so unique that we lack the basic vocabulary to describe it. Such is the case with this marble-raising dot-matrix alphanumeric display. But it’s pretty cool, so we’ll give it a shot.
The core — literally — of [Shinsaku Hiura]’s design is a 3D-printed cylinder with a spiral groove in its outside circumference. The cylinder rotates inside a cage with vertical bars; the bars and the grooves are sized to trap 6-mm AirSoft BBs, which are fed into the groove by a port in the stationary base of the display. BBs are fed into the groove at the right position to form characters, which move upwards as the cylinder rotates. Just watch the video below — it explains it far better than words can.
The clever bit is how the BBs are fed into the groove. Rather than have a separate mechanism to gate the feed port, there’s a backlash mechanism that opens the port when the motor powering the drum runs in reverse for a bit. It’s a clever use of cams to get the job done without adding an extra servo, which sort of reminds us of the design parsimony exhibited in his one-servo seven-segment display.
It’s not clear that this would be a very practical display, but that doesn’t stop it from being cool. Although, [Shinsaku Hiura] just released a follow-up video showing a bigger version of this used to display upcoming events from Google Calendar, so perhaps we’re wrong.