Design of the Week: 7 Segment Controller

By on November 18th, 2019 in Design

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 The 7 Segment Controller [Source: Cults]
The 7 Segment Controller [Source: Cults]

This week’s selection is the awesome 7 Segment Controller by Cults contributor Florian Hu.

What’s a “7 Segment Controller”? It’s something you have likely seen very often, but not necessarily realized what’s going on behind the scenes. Essentially it is a way to active seven “segments” arranged in a figure-8 pattern to show different digits, like something you’d see on an old clock radio.

The 7 Segment Controller is hand-operated via a handy crank. Just turn the crank and the mysterious 3D printed gears inside the contraption will flip the segments to show the next digit. Continuous cranking will carry you through the display of digits “0” through “9”.

 Interior view of the 7 Segment Controller [Source: Cults]
Interior view of the 7 Segment Controller [Source: Cults]

Hu explains the challenges of making this project:

“Do you love building mechanical contraptions? Complicated looking gear trains that perform some task? Then this kit is for you !

However, beware. It is not for the faint-hearted. The assembly instructions are 26 pages long. The counter comprises of well over 100 parts.”

This project could be the most complex yet appearing on Fabbaloo’s Design of the Week. Just 3D printing more than 100 parts would certainly take a considerable amount of time to complete, let alone the assembly.

Fortunately, the 7 Segment Controller is accompanied with detailed visual instructions on how to put the machine together.

 Sample sheet from the 7 Segment Controller assembly instructions [Source: Cults]
Sample sheet from the 7 Segment Controller assembly instructions [Source: Cults]

Hu explains there is a “reverse gear set” that can be used instead of the default if you wish the digits to count down instead of counting up. As well, it’s possible to replace the manual crank with a motor to automatically shift digits.

If the motor was controlled by software, then the digits could convey useful information in a specific application, such as counting runners passing the finish line, for example.

The STL files and instructions for building the 7 Segment Controller are available for download on Cults, a popular 3D model repository. However, they are not freely downloadable.

 3D printd parts for the 7 Segment Controller [Source: Cults]
3D printd parts for the 7 Segment Controller [Source: Cults]

Hu has set a download price of a whopping €6.86 (US$7.57) for the package. While that’s a lot more than “free”, it is completely understandable given the complexity of this design. Hu must have spent weeks developing this project, and deserves a reward. Besides, the remainder of the project will also cost you in terms of 3D printing material, other parts and of course, your own time.

Via Cults

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!