Flip-Segment Digital Clock Is A Miniature Mechanical Marvel

Clocks are such mundane objects that it’s sometimes hard for them to grab your attention. They’re there when you need them, but they don’t exactly invite you to watch them work. Unless, of course, you build something like this mechanical flip-segment clock with a captivating exposed mechanism

“Eptaora” is the name of this clock, according to its inventor [ekaggrat singh kalsi]. The goal here was to make a mechanical flip-segment display as small as possible, which meant starting with the smallest possible printable screw hole and scaling the design up from there. Each segment is controlled by a multi-lobed cam which bears on a spring-loaded cam follower. When the cam rotates against the follower, a segment is flipped up from the horizontal rest position to the vertical display position. A carryover mechanism connects two adjacent displays so that each pair of digits can be powered by a single stepper, and the finished clock is quite small — a little bit larger than the palm of a hand. The operation seems quite smooth, too, which is always a bonus with clocks such as these. Check out the mesmerizing mechanism in the video below.

We’d have sworn we covered a similar clock before — indeed [ekaggrat] says the inspiration for this clock came from one with a similar mechanism — but we couldn’t find it in the back catalog. Oh sure, there are flip-up digital clocks and all manner of mechanical seven-segment displays, but this one seems to be quite unique, and very pleasing.

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Seven Segments, But Not As We Know Them

We’ve seen a lot of clever re-imagining of the classic 7-segment display, and proving there is still room for something new is [Jack]’s 7-segment “DigiTag” display.

This 3D printable device has a frame into which is slotted three sliders. These sliders can be adjusted individually, mixing and matching the visibility of colored and uncolored areas, to create digits 0-9. We’ve seen some unusual 7-segment-inspired displays before, using from one motor for the whole digit to ones that need one motor per segment, but nothing quite like this approach.

While this particular design relies on the user to manually “dial in” each digit, the resulting key-like assembly (and unique shape for each digit) seems like it could have some interesting applications — a puzzle box design comes to mind.

If you have any ideas of your own on how this could be used, don’t keep them to yourself! Let us know in the comments, below.

Mouse Finds New Home In Pinball Machine

Restoring pinball machines is an excellent hobby, and can even be more than that as we see businesses like bars and museums focusing on them as a main attraction. There’s all kinds of intrigue to be found, from esoteric mechanical systems to classic electronics and unique artwork. For those building new pinball machines, though, one way to bypass a lot of the hassle of finding antiquated parts is to build a digital machine with an analog feel, like this machine which repurposes a computer mouse in an interesting way.

One of the important design considerations with a more modern system like this is to preserve the mechanical components that the player interacts with, in this case the plunger. This pinball machine is really just a large screen driven by a computer, but the plunger is a spring-loaded one from an old analog machine. Attached to the end of the plunger inside the cabinet is a cloth strap which passes underneath an old optical mouse. When the plunger is pulled and released, the mouse registers the position of the plunger and sends that information to the computer controlling the pinball display.

We really appreciate a KISS-style design like this in general. Mice are a proven, reliable technology and the metal components of the plunger are unlikely to ever wear out, which means that at least this part of the new pinball machine is unlikely to need much maintenance over the lifespan of the cabinet itself. For other ways of preserving the original feel of old machines, take a look at this build which incorporates all kinds of tricks within a MAME cabinet.

Custom Calculator Brings Us Back To The 70s

There are certain design aesthetics from every era that manage to survive the fads of their time and live throughout history. Ancient Greek architecture is still drawn upon for design inspiration in modern buildings, the mid-century modern style from the 60s still inspires various designs of consumer goods, and the rounded, clean looking cars from the 90s are still highly desirable qualities in automotive design. For electronics, though, we like this 70s-inspired calculator that [Aaron] recently built.

The calculator hearkens back to the days of calculators like the HP-29C with its large buttons and dot-matrix display. [Aaron] built the case out of various woods with a screen angled towards the user, and it uses a LCD display similar to those found in antique calculators. The brain of the calculator is an Arduino which fits easily into the case, and [Aaron] also built the keyboard from scratch with Cherry MX-style mechanical keys soldered together into a custom shape.

The software to run the calculator is fairly straightforward, but we are most impressed with the woodworking, styling, and keyboard design in this build. [Aaron] is also still ironing out some bugs with the power supply as it uses a DC-DC converter to power the device from a single lithium battery. For those who are more fond of early 2000s graphing calculators instead, be sure to take a look at this graphing calculator arcade cabinet.

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A man welds on a chassis

Electric Wheelchair Dump Truck Hack Really Hauls

Have you ever looked at a derelict electric wheelchair and thought “I bet I could make something great with that!” Of course you have- this is Hackaday, after all! And so did [Made in Poland], who managed to get a hold of a broken down electric wheelchair and put the full utility of his well equipped metalworking shop to work. The results? Lets just say it hauls.

What we really enjoyed about the build was that there wasn’t much that couldn’t be done by an average garage hacker with a drill press, angle grinder, and a stick welder. While it’s definitely nicer to have a lathe and a high quality welding table, plasma cutter, and everything in between, nothing that [Made in Poland] did in the video is such high precision that it would require those extensive tools. There may be some parts that would be a lot more difficult, or lower precision, but still functional.

Another aspect of the build is of course the control circuitry and user interface. Keeping the skid steer and castor approach meant that each motor would need to be controllable independently. To achieve this, [Made in Poland] put together a purely electromechanical drive controlled with momentary rocker switches and automotive relays to form a simple H-Bridge for each motor.

Of course you just have to watch until the end, because it really proves that a man will do anything to get out of hauling wood around! Old electric wheelchairs can also make a great base for big robots, as it turns out.

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An orange 3D printed four digit clock with rotating segments

Be Mesmerized By The Latest Time Twister

[Hans Andersson] has been creating marvelous twisting timepieces for over a decade, and we’re pleased to be able to share his latest mechanical clock contraption with our readers, the Time Twister 5.

In contrast to his previous LEGO-based clocks, version five of the Time Twister uses 3D printed segments, undoubtedly providing greater flexibility in terms of aesthetics and function. Each digit is a mechanical display, five layers vertical and three segments horizontal, with a total of three unique faces. Each layer of each display can be individually rotated by a servo, and this arrangement allows for displaying any number between zero and nine. The whole show is controlled by an Arduino MEGA and a DS3231 real-time clock.

Watching these upended prisms rotate into legible fifteen-segment digits is enjoyable enough already, but the mechanical sound created by this timepiece in motion is arguably even more satisfying. Check out the video below to see (and hear) for yourself. If you want to build one yourself, all the details are here.

We last covered [Hans Andersson] and his very first Time Twister clock way back in November 2011. Since then we’ve come across many impressive mechanical clocks, like this seven-segment work of art. We’re constantly impressed by the outstanding craftsmanship of these mechanical clocks, and it’s inspiring to see one of our OG horologists back in the saddle once more.

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The End Of The Electromechanical Era

When viewed from the far future, the early years of the 21st century will probably be seen as the end of a short era in human technological development. In the beginning of the 20th century, most everything was mechanical. There were certainly some electric devices, but consumer products like gramophone players and “movie” cameras were purely mechanical affairs. You cranked them up, and they ran on springs. Nowadays, almost every bit of consumer gear you buy will be entirely electronic. In between, there was a roughly 50 year period that I’m going to call the Electromechanical Era.

Jenny List’s teardown this week of an old Fuji film movie camera from 1972 captures the middle of this era perfectly. There’s a small PCB and an electric motor, but most of the heavy lifting in the controls was actually put on the shoulders of levers, bearings, and ridiculously clever mechanisms. The electrical and mechanical systems were loosely coupled, with the electrical controlled by the mechanical.

I’m willing to argue the specifics, but I’d preliminarily date the peak of the Electromechanical Era somewhere around 1990. Last year, I had to replace all of the rotted rubber drive belts in a Sony Walkman WM-D6C, a professional portable tape player and recorder produced from 1984-2002.

It’s not a simple tape recorder — the motors are electronically regulated to keep ridiculously constant speed for such a small device, and mine has Dolby B and C noise reduction circuitry packed inside along with some decent mic preamps. But still, when you press the fast-forward button, it physically shoves rubber-coated drive wheels out of the way, and sliding pieces of metal make it change modes of operation by making and breaking electrical contacts. Its precision lies as much in the mechanical assemblies and motors as in the electronics. It’s truly half electronic and half mechanical.

But that era is long over. The coming of the CD player signaled the end, although we didn’t see it at the time. Sure, there is a motor, but all the buttons are electronic, and all the “mechanism” is implemented almost entirely in silicon. The digital camera was possibly the last nail in the Electromechanical Era’s coffin: with no need to handle physical film, the last demand for anything mechanical evaporated. Open up a GoPro if you don’t know what I mean.

While I’ll be happy to never have to replace the drive rubber in a cassette recorder again, it’s with a little sadness that I think on the early iPods with their spinning metal hard drives, and how they gave way to the entirely silicon Zoom H5 recorder that I use now. It has a S/N ratio and quiet pre-amps, no wow or flutter, and a quality that would have been literally unbelievable when I bought the WM-D6C.

Still, if you find yourself in the thrift store, and you’ve never done so before, buy and take apart one of these marvels from a bygone era. A cassette recorder, even a cheap one, hides a wealth of electromechanical design.