Design of the Week: 3D Printed Electromechanical 7-Segment Display

By on January 20th, 2025 in Design, news

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3D printed electromechanical display [Source: YouTube]

This week’s selection is the 3D Printed Electromechanical 7-Segment Display by Instructables contributor tin-foil-hat.

If you’re old enough you might recall the pre-LCD digital displays found in clock radios or large public numerical displays. Each digit position held a stack of ten digits, which would rotate around to display the proper number. Sometimes you could hear the digits flip.

Those days are long gone, but you can reminisce about them with the 3D Printed Electromechanical 7-Segment Display. This project builds a four-digit electromechanical digital display that can be used for a variety of applications, including a counter, clock and more.

Why build this? “Hat” explains:

  • “I have always been enchanted by the old split-flap designs that used to fill train stations. With the modern digital era, we have lost some of the beauty of moving mechanical displays. The mechanical and tactile approach to displaying numbers and words is an interesting concept, and the clicking noise it makes is like nothing else. However, there are already plenty of people on the internet who have re-created these displays, and for that reason, I decided, why not re-invent a new mashup of mechanical displays?”
Parts for the electromechanical display [Source: Instructables]

This is an ambitious project, involving quite a few parts, both 3D printed and not. The display elements, for example, are all separately 3D printed parts. There are quite a few electronics components required to operate the display, including an Arduino controller.

Is there a motor required for this project. It turns out not, as the display elements are operated by electromagnets. As the elements are energized, the 3D printed elements flip. By carefully controlling the sequencing one can display numbers or other symbols on the seven-segment digits.

There is quite a bit of work to put this project together, but “hat” provides extraordinary detail on how to perform each step, including testing. They also provide cautions for critical steps to help you avoid disaster.

If you have a 3D printer, are handy with electronics projects and have a nostalgic sense for clock radios, this is your project for the week.

Via Instructables

By Kerry Stevenson

Kerry Stevenson, aka "General Fabb" has written over 8,000 stories on 3D printing at Fabbaloo since he launched the venture in 2007, with an intention to promote and grow the incredible technology of 3D printing across the world. So far, it seems to be working!