July 20th, 2021—
Seven-segment displays have been around for ages, and they have a really cool retro aesthetic about them. Over on Instructables, user alstroemeria (known as Jacky Mok in real life) decided to build a different kind of display that utilizes individual servo motors to slide the segments out, thus creating a 3D clock. The main board in this project was the Arduino Mega, which was selected due to its large number of digital GPIO pins that can set all 28 of the servos to the correct positions.
The current time was tracked using the DS3231 RTC module that stores the time and can keep it even if power is removed. The program Mok wrote first initializes the servos and sets them in the “off” position. Within the main loop, the time is retrieved from the RTC module and converted into digits. From here each digit is mapped to a series of segments which are then moved into the correct spot with the corresponding motor.
The clock enclosure Mok designed is quite elegant and captures the feeling of a classic seven-segment display. As seen in the accompanying video, watching the digits slowly move and morph into various shapes can be mesmerizing. More details on the concept and its construction can be found on Instructables.