Servo-Powered 7-Segments Choreograph This Chronograph

Good clocks are generally those that keep time well. But we think the mark of a great clock is one that can lure the observer into watching time pass. It doesn’t really matter how technical a timepiece is — watching sand shimmy through an hourglass has its merits, too. But just when we were sure that there was nothing new to be done in the realm of 7-segment clocks, [thediylife] said ‘hold my beer’ and produced this beauty.

A total of 28 servos are used to independently control four displays’ worth of 3D-printed segments. The servos pivot each segment back and forth 90° between two points: upward and flat-faced to display the time when called upon, and then down on its side to rest while its not needed.

Circuit-wise, the clock’s not all that complicated, though it certainly looks like a time-consuming build. The servos are controlled by an Arduino through a pair of 16-channel servo drivers, divided up by HH and MM segments. The Arduino fetches the time from a DS1302 RTC module and splits the result up into four-digit time. Code-wise, each digit gets its own array, which stores the active and inactive positions for each servo. Demo and full explanation of the build and code are waiting after the break.

When it comes to 7-segment displays, we say the more the merrier. Here’s a clock that uses pretty much all of them.

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Mini-VFD Clock Floats The Display Above It All

As [sjm4306] says, “You can never have too many clocks based on obsolete display technologies.” We couldn’t agree more, and this single-tube VFD clock is one we haven’t seen before.

The vacuum-fluorescent display that [sjm4306] chose to base this clock on is the IV-21, an eight-digit seven-segment display on the smallish side. The tube is Russian surplus from the ’80s, as all such displays seem to be. The main PCB sports an ATMega328, a boost converter to provide the high voltage needed to run the VFD, a real-time clock, and the driver chip for the tube segments. The tube itself lives on a clever riser card that elevates the display above the main PCB and puts it at the proper angle for reading. [sjm4306] designed it to be modular; should you want to user a bigger VFD you need only make a new riser PCB. Figuring out the proper way to space the through-holes in Eagle proved elusive, but he hacked a solution using a spreadsheet to handle the trigonometry and spit out Cartesian coordinates for each hole. Pretty neat. The video below shows the clock assembly and a test.

We really like the look of this clock for some reason – perhaps it’s the quirky nature of the VFD, or the soft teal glow of the digits. We’ve featured plenty of clocks with odd displays before: VFDs large and small, faux-NIMO, de-encapsulated LED “filaments”, and lots and lots of Nixies.

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