Marble Text Display
Ivan Miranda has finished a marble scroller, a workshop sized machine that writes lines of text using nothing but small black and white marbles. He walks through the whole build in a video on his own channel, and the finished rig fills the bench it stands on. Unlike his earlier marble clocks, this one does not stop at a few digits.
Miranda made his name with mechanical clocks that show the time in marbles, and Interesting Engineering reports that the scroller moves that idea from digits to letters. The switch sounds small and is not. A clock changes a handful of characters in a tight space, while a text display has to line up whole letters and words across a surface far too wide to print in one piece.
And the frame is circular for that reason. Miranda built the display as a wide ring, so a finished row can rotate out of view while a fresh one is loaded behind it. That loop is what lets the machine write a message of any length rather than a single short word.
Every marble has to be given a job before it reaches the rim. A motorised selector arm sits between the feed and the display tracks, and an infrared sensor on the arm reads the colour of the marble it is holding. Black goes one way and white goes the other, so each marble lands on the track that builds the correct letter at the right position on the ring.
Most of the structure came off desktop 3D printers. The ring, the tracks, and the guides that carry each marble are printed, and the bought parts are limited to steel ball bearings and the stepper motors that drive the machine. Miranda has printed his own parts for years, and the scroller is simply a much larger use of the same method.
But the machine is not a precision instrument in the way a screen is. Letters sometimes arrive crooked, and Miranda corrects the alignment by hand before it settles back into writing cleanly. The flaws are part of the format, because every character is drawn by where a marble happens to land.
The recycling is the clever part of the loop. Once a row of letters passes the display window, the marbles drop into a collector underneath and are carried back to the start of the feed. Nothing is thrown away, nothing is printed with ink, and the same few thousand marbles make every character the machine shows.
Miranda says the project took far more time than he expected and ranks it as the build he underestimated most. He has asked viewers for ideas on making it run faster, which suggests the current speed is not his final answer. The video runs well past half an hour and is mostly build footage from the bench rather than a packaged demo.
So there is no product here. The scroller is a single build in a maker workshop, and neither Miranda nor any retailer has put a price on it or offered it for sale.
Miranda turns black and white marbles into lines of text on a large printed ring.
A motorised selector arm with an infrared sensor sorts each marble onto the right track.
Steel bearings and stepper motors turn the ring, and dropped marbles are fed back in.
The machine is a single maker build, with no product or price attached.
Source: Ivan Miranda
