Mechanical 7-Segment Display Cycles Through Digits Without Any Electronics

Seven-segment displays date back to the early 20thcentury—before digital electronics even existed—and still remain popular today. That’s because just seven LEDs can be used to show each of the ten numerical digital in the decimal numbering system. Multiple seven-segments displays can be chained together to display multi-digit numbers. But virtually all seven-segment displays are controlled digitally, or at least electromechanically. This mechanical seven-segment counter, on the other hand, can cycle through all ten digits without using any electronic components at all.

This contraption doesn’t serve much of a practical purpose, but it is a marvel of mechanical design that is reminiscent of the intricate mechanisms that were engineered before the digital age. Like a fine Swiss watch, it uses a series of complex gears. Those convert rotary motion of the crank into toggling of each segment. It manages to do that in sequence to count up through the digits, before starting back over at zero. It cannot be cranked in reverse to count down, but there is a reverse gear set available that you can use to achieve that.

Seven-segment displays date back to the early 20th century—before digital electronics even existed—and still remain popular today. That’s because just seven LEDs can be used to show each of the ten numerical digital in the decimal numbering system. Multiple seven-segments displays can be chained together to display multi-digit numbers. But virtually all seven-segment displays are controlled digitally, or at least electromechanically. parts to the enclosure. That enclosure is also 3D-printed, but with wood filament to give it some aesthetic appeal. Building this yourself is going to be a serious project, but watching the mechanisms is mesmerizing and it does a great job of demonstrating what is possible with thoughtful design work.