Today’s tale of being in the right place at the right time comes from [fabe1999], who was doing an intern gig at the airport when the controller on their split-flap display bought a one-way ticket going south. They were just going to throw away thousands of these letters and replace them with monitors, but the intern intervened.
[fabe1999] grabbed an armload, took them home, and set about making them flap again, one letter at a time. An ATtiny worked okay, but it wasn’t really fast enough to flip them at their full clacking potential, so [fabe1999] switched to an ESP8266. So now there is one ESP for each of the 20 characters, and another that runs a web server where text can be directly entered for immediate display.
Each letter uses two sensors to flap to the right letter. The first one acts as a start sensor, detecting the blackness of a blank character. Another sensor counts the letters and makes the ESP stop the motor on the right one. So far, [fabe1999] hasn’t figured out how to recognize when a blank character can stay blank, so they flap all the way around back to blank for now. It certainly adds to the rich, flappy sound, but that can’t be good for the long-term life of the letters. Your flight is now departing for Post Break Island, where the letters are spending part of their retirement showing song titles from Spotify.
No chance of split flaps falling into your lap? Here’s a tip: you can fab your own flip.
Continue reading “Airport Split-Flap Letters Carry On As Spotify Display”
Why would anyone put as much effort into resurrecting a 1970s split-flap clock as [mitxela] did when he built this custom PLL frequency converter? We’re not sure, but we do like the results.
The clock is a recreation of the prop from the classic 1993 film, Groundhog Day, rigged to play nothing but “I Got You Babe” using the usual sound boards and such. But the interesting part was getting the clock mechanism keeping decent time. Sourced from the US, the clock wanted 120 VAC at 60 Hz rather than the 240 VAC, 50 Hz UK standard. The voltage difference could be easily handled, but the frequency mismatch left the clock running unacceptably slow.
That’s when [mitxela] went all in and designed a custom circuit to convert the 50 Hz mains to 60 Hz. What’s more, he decided to lock his synthesized waveform to the supply current, to take advantage of the long-term frequency control power producers are known for. The write-up goes into great detail about the design of the phase-locked loop (PLL), which uses an ATtiny85 to monitor the rising edge of the mains supply and generate the PWM signal that results in six cycles out for every five cycles in. The result is that the clock keeps decent time now, and he learned a little something too.
If the name [mitxela] seems familiar, it’s probably because we’ve featured many of his awesome builds before. From ludicrous-scale soldering to a thermal printer Polaroid to a Morse-to-USB keyboard, he’s always got something cool going on.
There are plenty of ways to make large alphanumeric displays that are readable at great distances. LED signboards come to mind, as do big flat-screen LCD displays. But such displays feel a little soulless, and nothing captures the atmosphere of a busy train station like an arrivals and departures board composed of hundreds of split-flap displays.
In a bid to make these noisy but intriguing displays practical for the home-gamer, [Scott Bezek] has spent the last couple of years on a simple, modular split-flap display unit, and from the look of the video below, it’s pretty close to ready. The build log details the design process, which started with OpenSCAD and took advantage of the parametric nature of the scripting language to support any number of characters, within reason. Costs are kept low with laser-cut MDF frames and running gear, and cheap steppers provide the motion. Character cards are just PVC ID badges with vinyl letters, and a simple opto-sensor prevents missed steps and incorrect characters. The modules can be chained together into multi-character displays, and the sound is satisfyingly flappy.
[Scott] has put a lot of thought into these displays, and even if it’s not the simplest split-flap display we’ve seen, it’s really worth checking out.
Continue reading “Easy, Modular Alphanumeric Displays Are Full Of Flappy Goodness”
[WolfCat] of Wolfcatworkshop is creating a hand-animated split-flap animation. But what do you use to test your animation once it’s on the split-flaps? Well, to test it out, [WolfCat] used a drill to give it motion. DoodlersAnonymous has some pics and an interview with [WolfCat] about his animation and there are some pictures on his Instagram page.
Technically, what [WolfCat] wanted to make is a “mutoscope,” a hand-cranked precursor to the movie projector that had its heyday in the late 19th and early 20th century. Originally installed in penny arcades and the like, mutoscopes were single-viewer apparatus. The viewer cranks the handle and the animated cards inside rotate around, stopped briefly by a bit of metal at the top in order to show a frame. The basic idea is similar to the way split-flap clocks or signs work.
[WolfCat] hand drew the animation for his movie and then scanned and printed out each frame. The frames were then transferred to a pair of flaps. [WolfCat] wanted to see how it would look when animated, but didn’t have any plans at the time for a case or a hand crank, so he found the closest tool that would do the job – a cordless drill. Attaching the drill and using a bit of card or wood as a stopper, [WolfCat] could see how the end result would look and could then start work on the case and crank.
The drill is a quick and easy way to see what the finished product would look like. Once he’s got it working, [WolfCat] could check out this 3D printed mutoscope case, or this flip dot animated display.
Continue reading “Use A Drill To Power Your Flipbooks”
[John] got his hands on a 3D printer, and did what any hacker with a new toy would, printed himself a Mutoscope. (A what?) A Mutoscope is an early flip-book based motion picture machine, and in this case it displays 24 frames from “A Clockwork Orange”. [John]’s 3D-printed machine is, not coincidentally we assume, printed in orange plastic.
The model for the frame is up on Thingiverse, but there’s not all that much to it, honestly. It’s a frame and a few wheels that hold some skewers in place. The rest of the work is making the flaps.
But getting to the end product wasn’t a straight walk. [John] describes all of the starts and stops in his blog, aptly named “Fail Try Again”. We like seeing the whole process rather than just the final, seventh, iteration of the device.
Where to take this project next? We want to see a design with a mounting bracket for a cheap stepper motor built in. We’ve always wanted our own custom signage, and there’s nothing cooler than the flap-flap-flap noise that flip book pages make when being switched. We must not be alone in thinking so, because we’ve seen two beautiful DIY builds in the last two years: this one done in multiples for advertising purposes and this one done just for the lulz. [John]’s project is a lot simpler, and thus a lot more accessible. We hope it inspires a few of you to make your own.
Beautifully documented, modular, and completely open-source, this split flap display project by [JON-A-TRON] uses 3D printing, laser cutting and engraving, and parts anyone can find online to make a device that looks as sharp as it is brilliantly designed. Also, it appears to be a commentary on our modern culture since this beautifully engineered, highly complex device is limited to communicating via three-letter combos and cat pictures (or cat video, if you hold the button down!) As [JON-A-TRON] puts it, “Why use high-resolution, multi-functional devices when you can get back to your industrial revolution roots?” Video is embedded below.
Continue reading “Complex, Beautiful Device Is Limited To Text-speak And Cat Pictures (WTF, LOL)”
A short but highly detailed documentary by [Krzysztof Tyszecki] explores the split-flap display system in place at the Łódź Kaliska train station in Poland as well as the efforts needed by the staff to keep it running and useful to this day. Split-flap displays might be old technology, but many are still in use throughout the world. But even by those standards, the unit at Łódź Kaliska is a relic you wouldn’t expect to see outside a museum. “I doubt you’ll find an original anywhere else,” says a staff member. It requires constant upkeep to remain operational, and meeting the changing demands of a modern station within the limitations of the original system takes some cleverness. “In general the failure rate of the device is terrible,” he adds.
The system runs on punch cards. You can’t buy them anymore, so a local printer makes them – several hundred are needed every time there is a schedule change. The punching pliers (which also can no longer be purchased) get so worn out they replace the pins with custom-made ones from a local locksmith. The moving parts of the card reader have split-pins which need to be replaced every week or two – the stress of repeated movement simply wears them away. There’s nothing to do but replace them regularly. The assembly needs regular cleaning since dust accumulates on the cards and gets into the whole assembly. The list goes on… and so does the station.
There is no computation in the modern sense – it’s an electromechanical signing system managed and updated by human operators. It has more in common with a crossbar switch based telephone exchange than anything else. The punch cards are just a means of quickly, accurately, and repeatedly setting the displays to known states.
The short documentary goes into a lot of detail about every part of the system. The cards themselves are described in detail (1:07), as is the operator’s routine (2:27). We even see the back end controller (9:41), as well as see a split-flap module taken apart and tested (14:33) with an old tester the staffer isn’t sure will even work – but as with everything else we see, of course it does.
Split-flap displays are fascinating pieces of technology. We have even seen people build their own split-flap displays from scratch!
Continue reading “Split-flap Train Display Uses Punch Cards; Serviced With Station Ingenuity”