A 1960s Copal flip clock

Classic 1960s Flip Clock Gets NTP Makeover

Many of the clocks we feature here on Hackaday are entirely built from scratch, or perhaps reuse an unusual display type. But sometimes, an old clock is just perfect as it is, and only needs a bit of an upgrade to help it fit into the modern world. One such example is the lovely 1960s Copal flip clock (in German, Google Translate link) that [Wolfgang Jung] has been working with — he managed to bring it squarely into the 21st century without changing its appearance one bit.

Like most flip clocks from the 60s and 70s, the Copal clock uses a small synchronous AC motor to advance the digits. Because this motor runs in step with the mains frequency, it also acts as the clock’s timing reference. However the original motor had died, and a direct replacement was impossible to find. So [Wolfgang] decided to replace it with a modern stepper motor. He designed a small PCB that fit the original housing, on which he placed a Trinamic TMC2225 stepper motor driver, a Wemos D1 Mini and a small 5 V power supply.

A flip clock mechanism with a PCB attached to itThanks to its WiFi connection, the D1 can find out the correct time by contacting a Network Time Protocol (NTP) server. Displaying that time would be tricky with the original hardware though, because there is no indication of which numbers are displayed at any time. [Wolfgang] cleverly solved this problem by placing an IR proximity sensor near the lowest digit, allowing the D1 to count the number of digits that have flipped over and thereby deduce the current state of the display.

There’s plenty of fun to be had with classic flip clocks like this, and with a bit of hacking any old split-flap display should be usable for your own clock project. If none are available at your local thrift store or yard sales, you can always roll your own.

Flip-up clock

A Flip Clock That Flips Up, Not Down

The venerable flip clock has become an outsized part of timekeeping culture that belies the simplicity of its mechanism. People collect and restore the electromechanical timepieces with devotion, and even seek to build new kinds of clocks based on split-flap displays. Designs differ, but they all have something in common in their use of gravity to open the leaves and display their numbers.

But what if you turned the flip clock on its head? That’s pretty much what [Shinsaku Hiura] accomplished with a flip clock that stands up the digits rather than flipping them down. The clock consists of three 3D-printed drums that are mounted on a common axle and linked together with gears and a Geneva drive. Each numeral is attached to a drum through a clever cam that makes sure it stands upright when it rotates to the top of the drum, and flops down cleanly as the drum advances. The video below makes the mechanism’s operation clear.

The build instructions helpfully note that “This clock is relatively difficult to make,” and given the extensive troubleshooting instructions offered, we can see how that would be so. It’s not the first time we’ve seen a mechanically challenging design from [Shinsaku Hiura]; this recent one-servo seven-segment display comes to mind.

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A Vintage Flip Clock Gets Some Modern Love

There are multiple reasons why we like [iSax]’s rebuild of a Bodet flip clock from the early 1980s. First there’s the retro charm of the timepiece itself, then the electronics used to drive it, its electromechanical month length and leap year system, and finally because here is a maker lucky enough to have a beautiful tabby cat to share the workbench with.

For those of you unfamiliar with a flip clock, these devices have their digits as a series of hinged cards on a central rotor, with each one being exposed in turn as the rotor turns. This one is part of a distributed clock system in which the clients receive a 1 Hz pulse from a central time server to drive their motors, something easily replicated with an Arduino and an H-bridge. Particularly fascinating though is the month length mechanism, part of the calendar rotor system, it has a small DC motor that is engaged to advance the days automatically by whichever number as part of the month transition. Originally this was powered by a couple of AA batteries, which have now been replaced with a small DC to DC converter. You can see it in action in the video below the break.

With or without tabby cats, we see quite a few projects featuring them. If you can’t find one, you can always make your own.

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3D Printed Flip Clock Is Worth A Second Look

Flip clocks: they were cool long before Bill Murray was slapping one repeatedly in Groundhog Day, they were cool in 1993, and they’re still cool now. If you can’t find one on the secondhand market, you’re in luck, because [iz2k] has laid out an extensive blueprint for building a gorgeous retro-looking clock with some modern touches.

There’s a Raspberry Pi to fetch the time, the weather, and the Spotify. Old flip clocks invariably tuned in FM radio, so [iz2k] used an RTL-SDR dongle and a software decoder for the deed. This clock even has a big snooze bar, which functions like a night light when there is no alarm actively going off. The three groups of painstakingly-printed flaps are controlled with stepper motors and an IR transmitter/receiver pair to do the counting.

For the interface, [iz2k] kept things nice and simple. The big-knobbed rotary encoder handles volume up/down/mute, and the little one on the front switches between FM radio, Spotify, and silence. Moving either knob generates feedback by flashing LEDs that sit underneath the display. Take a few seconds to flip past the break and check out the short demo.

If you do find a nice flip clock out in the wild, maybe you can retrofit it.

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Retro Flip Clock Gets A Retrofit

Retro tech is almost always ripe for the hacking — be it nostalgia, an educational teardown, or acknowledging and preserving the shoulders upon which we stand. Coming across an old West-German built flip clock, YouTuber [Aaron Christophel] retrofitted the device while retaining its original mechanical components!

No modern electronics are complete without LEDs of some kind, so he has included a strip in the base of the clock face for visibility and cool factor. He doesn’t speak to the state of the clock beforehand, but he was able to keep the moving bits of the clock working for its second shot at life.

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Seven-Segment Flip Clock Display Finally Finished

Earlier this year, we mentioned in a Hackaday Links article that [Spencer Hamblin] was in the process of building a seven-segment flip clock. Well, it’s finally finished, and it looks great!

Vintage seven segment digits make up the display. These digits work the same way that flip-dot displays work – current through each segment’s coil creates a magnetic field which causes the segment to flip over. Current in the other direction creates the opposite magnetic field and flips the segment the other way. On these digits, there are three connections on the coils. The middle one is power and the other two are used to enable and disable the segment – ie., flip it one way or the other. To save on pins on the microcontroller, [Spencer] connected all the middle coil pins together on a digit. Each coil can be powered using a single pin on the microcontroller. Similarly, the segments for each digit are connected together as well, so one pin on the micro controls the same segment on each of the digits. The microcontroller in question is the AVR ATMega48.

There are two parts of the clock face left to do: AM/PM and whether the alarm is set or not. [Spencer] used a fifth digit, slightly offset, for those – the top and middle segments are used.

For the housing of the clock, [Spencer] used layers of offsetting colored wood. The wood (sapele and ash) were CNC cut and aligned. The back plate, also made from wood, holds buttons for setting the time and alarm, as well as some LEDs for what [Spencer] calls the “daylight alarm.” A capacitive sensor on the top of the unit (inside the wooden case) is used to turn the alarm off.

The result, after sanding and shellacing, looks amazing. [Spencer] nailed the art-deco look he was going for. There are plenty of pictures and the circuit designs, schematics and code are on [Spencer]’s Hackaday.io page, and you can find the Hackaday links post here. This is a complete log of a project we mentioned earlier on Hackaday, here, but there are other mechanical flip display clock projects, such as this DIY mechanical flip seven-segment prototype, or, you could create your own (really big) clock using this Lego mechanical seven-segment display.

via Reddit.

A cyclotron clock display, mounted on a wooden base. There are two stepper motors exposed on either side. There is a panel installed in the wooden base with a red button on the left, two knobs and four smaller buttons in a two by two grid on the right.

A Flipping, Perpetually-Rotating Clock

Clocks are a mainstay of hackers and makers, as they provide a way to explore creative designs while still maintaining a functional aspect to the project. [Brett Oliver] follows this tradition in making a cyclotron clock that uses a perpetual rotating digit concept from a 1900s desk flip calendar.

An exploded view of one of the flip calendar digit display, showing how the tiles fit into the chamber.

Each digit of the clock has a rotating chamber that’s big enough to fit a group of tiles inside that have digits printed on either face. The tiles are sized and stacked in such a way that the rotation of the chamber allows the next tile to slide in front of the old one. Specific digits are revealed by rotating the chamber a number of times.

Each of the four digits positions has a 28BYJ-48 stepper motor to rotate the chamber, with each motor being driven by a ULN2003 driver module. The main microcontroller is a ESP32 WROOM, and an I2C compatible DS3231 real time clock (RTC) module keeps time. All of the motors are driven off of an LM2596 module that provides 7 V, while the ESP32 and RTC are powered from a USB connector.

The different modes and the ability to set time is done through a panel that has various buttons and knobs. The whole clock is mounted on a custom wooden base that has cutouts for the panels and cabling. [Brett Oliver] has done a great job of documentation, going into detail about the mechanics and electronics of the build. Design files, including STLs of the various components, are also available for download. Be sure to check out the video after the break.

We’ve featured a flip calendar with a similar operating principle before which clearly shows the inner workings of the mechanism.

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