A woman in a richly-colored blue head scarf leans over a wooden table looking at the timer between her hands. The timer has a yellow circle on black flip panels on the left and black and white CT scans of a human torso on the right side. The frame is wood, and there is an electric motor on the upper right of the frame and a silver drum on the left of the frame beneath the woman's hand.

A Flip Clock Becomes A Flip Timer

June 6, 2025 by Navarre Bartz 2 Comments

Sometimes it’s nice to have a widget to do a single task and avoid getting distracted by the supposed simplicity of doing it with an app on a smartphone. [Dina Amin] built a timer from an old flip clock to stay focused.

Starting with a disassembly of the flip clocks she found at a flea market with [Simone Giertz], [Amin] decided to change the twenty four hour mechanism to a twenty four minute one which was similar to the amount of time she was already using for several different practices. Since she’s an expert in animation, she planned on turning a set of CT scans into the animation that would play on the section that had previously been the minutes of the clock.

As much of the original clock’s components were damaged, and [Amin] didn’t have a chance to learn clockmaking from scratch in a week, she tried a few different drive mechanisms for the build. The drum from an air fryer timer driven with an electric motor fit the bill, but off enough from proper minutes that [Amin] switched from numerals to a yellow circle that fills in as it approaches the satisfying ding of completion.

If you want to see Simone’s Moon flip clock we’ve covered that project too.

Continue reading “A Flip Clock Becomes A Flip Timer” →

A woman in a ball cap and black tank top holds a black and white image of the Moon printed on black acrylic. It can fold and is mounted on a black plastic mechanism with turning knobs affixed to the ends. There are out-of-focus shelves in the background with various items and books on them.

Moon Phase Flip Clock Is Fantastic

May 16, 2025 by Navarre Bartz 15 Comments

We love clocks, but we especially love unusual timepieces that aren’t just about showing the hour of the day. [Simone Giertz] built a flip clock moon phase tracker for a friend.

While in Egypt for Cairo Maker Faire, [Giertz] and [dina Amin] found some old flip clocks at a flea market and had to have them. [Amin] mentioned wanting to make a moon phase tracker with one, and [Giertz] decided to try her hand at making her own version. A side quest in more comfortable flying is included with the price of admission, but the real focus is the process of figuring out how to replicate the flip clocks original mechanism in a different size and shape.

[Giertz] cut out 30 semi-circle flaps from polystyrene and then affixed vinyl cut-outs to the flaps. The instructions for the assembly suggest that this might not be the best way to do it, and that printing stickers to affix to the flaps might work better since the cut vinyl turned out pretty fiddly. We really like the part where she built a grid jig to determine the optimal placement of the beams to keep the flaps in the right position after a disheartening amount of difficulties doing it in a more manual way. Her approach of letting it rest for twenty minutes before coming back to it is something you might find helpful in your own projects.

Best of all, if you want to build your own, the files are available for the flip moon station on the Yetch website. You’ll have to come up with your own method to drive it though as that isn’t in the files from what we saw.

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Classic 1960s Flip Clock Gets NTP Makeover

March 26, 2023 by Robin Kearey 14 Comments

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.

Thanks 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.

A Solari Mechanical Digital Clock Hack With A Little Extra

February 14, 2022 by Dave Rowntree 7 Comments

[Alfredo Cortellini] was perusing an antique shop in Bologna, and came across a nice example of a late 1950s timepiece, in the shape of a Solari Cifra 5 slave clock, but as the shop owner warned, it could never tell the time by itself. That sounded like a challenge, and the resulting hack is a nice, respectful tweak of the internals to bring it into the modern era. Since the clock requires a single pulse-per-minute in order to track time, the simplest track often followed is to open the back, set the correct time manually by poking the appropriate levers, and then let an external circuit take over clocking it. [Alfredo] wanted autonomy, and came up with a solution to make the thing fully adjust itself automatically.

Electronics-wise, initial prototyping was performed with a Nucleo 32 dev board and a pile of modules, before moving to a custom PCB designed in Altium Designer. An STM32G031 runs the show, with a few push buttons and a SSD1306 OLED display forming the UI.

Using some strategically-placed magnets and hall effect sensors, the status of the internal mechanism could be determined. Minute advancements were effected by driving the clock’s 24V electromagnet with a DRV8871 motor driver IC, the power supply for which was generated from the USB supply via a TPS61041 boost converter. In order to synchronise the mechanism with the electronics, the unit could have been driven to advance a minute at a time, but since every hour would need sixty pulses, this could take a while given the limited speed at which that could be done reliably. The solution was to sneak in a crafty MG996R high-torque servo motor, which pushes on the hour-advancement lever, allowing the unit to be zeroed much faster. Sensing of the zero-hour position was done by monitoring the date-advance mechanism, that is not used in this model of clock. Once zeroed, the clock could then be advanced to the correct time and kept current. Firmware source, utililising FreeRTOS can be found on the project GItHub, with schematics and Fusion360 files on the Hackaday.IO project linked above.

If you were thinking you’ve seen these Solari soft-flap displays here before, you’d be quite correct, but if you’re not so much interested in marking the passage of time, but bending such devices to your other indication whims, we’ve got you covered also.

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A Flip Clock That Flips Up, Not Down

November 24, 2021 by Dan Maloney 3 Comments

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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Steppers And ESP32 Make This Retro-Modern Flip-Clock Tick

October 2, 2021 by Dan Maloney 8 Comments

Before LEDs became cheap enough to be ubiquitous, flip-card displays were about the only way to get a digital clock. These entirely electromechanical devices had their own charm, and they have a certain retro cachet these days. Apart from yard sales and thrift stores, though, they’re a bit hard to source — unless you roll your own, of course.

Granted, [David Huang]’s ESP32-based flip clock is worlds apart from the flip cards of the “I Got You, Babe” era. Unfortunately, the video below is all we have to go on to get the story behind this clock, but it’s pretty self-explanatory. [David] started the build by making the flip cards themselves, a process that takes some topological tricks as well as a laser cutter. 3D-printed spools are loaded with the cards, which are then attached to frames that hold a stepper motor and a Hall-effect sensor. The ESP32 drives the steppers via L298N H-bridge drivers, but it’s hard to say if there’s an RTC chip or if the microcontroller is just getting time via an NTP server.

[David] might not be the only one trying to recapture that retro look, but we’ve got to hand it to him — it’s a great look, and it takes a clever maker to not only build a clock like this, but to make a video that explains it all so clearly without a single word of narration.

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A Vintage Flip Clock Gets Some Modern Love

January 2, 2021 by Jenny List 6 Comments

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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