Learning Through Play Hack Chat with Greg Zumwalt

Join us Wednesday at noon Pacific time for the Learning Through Play Hack Chat!

You may think you’ve never heard of Greg Zumwalt, but if you’ve spent any time on Instructables or Thingiverse, chances are pretty good you’ve seen some of his work. After a long career that ranged from avionics design and programming to video game development, Greg retired and found himself with the time to pursue pet projects that had always been on the back burner, including his intricate 3D-printed automata. His motto is “I fail when I decide to stop learning,” and from the number of projects he turns out and the different methods he incorporates, he has no intention of failing.

Please join us for this Hack Chat, where we’ll discuss:

  • Lifelong learning through play;
  • Toy-building as a means to skillset growth;
  • Sources of inspiration and getting new ideas; and
  • What sorts of projects Greg has in the pipeline.

You are, of course, encouraged to add your own questions to the discussion. You can do that by leaving a comment on the Learning Through Play Hack Chat and we’ll put that in the queue for the Hack Chat discussion.

join-hack-chatOur Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, March 13, at noon, Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

Ten 3D Printed Gadgets That Just Can’t Stay Still

There was a time, not so very long ago, when simply getting a 3D printer to squirt out an object that was roughly the intended shape and size of what the user saw on their computer screen was an accomplishment. But like every other technology, the state of the art has moved forward. Today the printers are better, and the software to drive them is more capable and intuitive. It was this evolution of desktop 3D printing that inspired the recently concluded 3D Printed Gears, Pulleys, and Cams contest. We wanted to see what hackers and makers can pull off with today’s 3D printing tools, and the community rose to the challenge.

Let’s take a look at the top ten spinning, walking, flapping, and cranking 3D printed designs that shook us up:

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7-Segment Display is 3D Printed and Hand Cranked

[Peter Lehnér] has designed a brilliant 7-segment flip-segment display that doesn’t really flip. In fact, it doesn’t use electromagnets at all. This one is 3D printed and hand cranked. It’s a clever use of a cam system to set the segments for each digit (0-9) makes it a perfect entry in the Hackaday 3D Printed Gears, Pulleys, and Cams contest.

We find the nomenclature of these displays to be a bit confusing so let’s do a quick rundown. You may be most familiar with flip-dot displays, basically a dot-matrix grid of physical pixels that are black on one side and brightly colored (usually chartreuse) on the other. We saw a giant flip-dot display at CES four years ago. Akin to flip-dots are flip-segment displays which do the same thing but with segments of a digit rather than dots. We featured a 3D printed version of these last week. The common aspect of most flip displays is an electromagnet used to change the state of the dot or segment.

The version [Peter] designed gets rid of the magnets and coils, replacing them with mechanical logic instead. Each segment sits in a track on the frame of the digit. When slid to one position it is hidden by the bezel, in the other position it slides into view. A cleverly designed set of cams move the segments at each of 10 positions. The animated graphic here shows three cams which are responsible for moving just two of the segments. More cams are added to complete assembly, a process shown in the second half of the demo video found below.

We’re delighted to see this as an entry in the contest and can’t wait to see what kind of gear, cam, or pully scheme is built into your projects!

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New Contest: 3D Printed Gears, Pulleys, and Cams

One of the killer apps of 3D printers is the ability to make custom gears, transmissions, and mechanisms. But there’s a learning curve. If you haven’t 3D printed your own gearbox or automaton, here’s a great reason to take the plunge. This morning Hackaday launched the 3D Printed Gears, Pulleys, and Cams contest, a challenge to make stuff move using 3D-printed mechanisms.

Adding movement to a project brings it to life. Often times we see projects where moving parts are connected directly to a servo or other motor, but you can do a lot more interesting things by adding some mechanical advantage between the source of the work, and the moving parts. We don’t care if it’s motorized or hand  cranked, water powered or driven by the wind, we just want to see what neat things you can accomplish by 3D printing some gears, pulleys, or cams!

No mechanism is too small — if you have never printed gears before and manage to get just two meshing with each other, we want to see it! (And of course no gear is literally too small either — who can print the smallest gearbox as their entry?) Automatons, toys, drive trains, string plotters, useless machines, clockworks, and baubles are all fair game. We want to be inspired by the story of how you design your entry, and what it took to get from filament to functional prototype.

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Frickin’ Amazing Clock

Wwood_clock_05e’ve featured a lot of clock builds, but this one, as the title suggests, is frickin’ amazing. Talented art student [Kango Suzuki] built this Wooden Mechanical Clock (Google translation from Japanese) as a project while on his way to major in product design. There’s a better translation at this link. And be sure to check out the video of it in motion below the break.

[Kango]’s design brief was to do something that is “easy for humans to do, but difficult for machines”. Writing longhand fits the bill, although building the machine wasn’t easy for a human either — he needed six months just to plan the project.

The clock writes time in hours and minutes on a magnetic board. After each minute, the escapement mechanism sets in motion almost 400 wooden cogs, gears and cams. The board is tilted first to erase the old numbers, and then the new numbers are written using four stylii.

The clock doesn’t have any micro controllers, Arduinos, servos or any other electronics. The whole mechanism is powered via gravity using a set of four weights. [Kango] says his biggest challenge was getting the mechanism to write the numbers simultaneously. While he managed the geometry right, the cumulative distortion and flex in the hundreds of wooden parts caused the numbers to be distorted until he tuned around the error.

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Retrotechtacular: Restoring A 19th Century Automaton


Made sometime in the 1790s or 1800s London, the Maillardet Automaton has a long and storied history. It was exhibited around England for several decades, brought over the Atlantic by [P.T. Barnum], nearly destroyed in a fire, and donated to the Franklin Institute in Philadelphia in the 1920s. From there, this amazingly complex amalgam of cogs, cams, and linkages eventually became the inspiration for the book – and movie – Hugo. Time hasn’t exactly been kind to this marvel of the clockmaker’s art; it has been repaired four times before receiving a complete overhaul in 2007 by [Andrew Baron].

[Fran], one of Hackaday’s sources for awesome projects, recently visited the Franklin Institute and posted a series of videos on the reverse engineering of the Maillardet Automaton. Being nearly destroyed and repaired so many times didn’t make this an easy job; it’s extremely possible no one alive has ever seen the eyes of the Automaton move as originally designed.

Even though the Maillardet Automaton has one of the largest series of cams of any mechanical draftsman, that doesn’t mean it’s simply an enlargement of an earlier machine. The automaton’s pen is like no other writing device on Earth, with a stylus acting as a valve to dispense ink whenever the tip touches paper. The eyes have linkages to follow the pen as it traces a drawing. In 1800, this automaton would have been a singularity in the uncanny valley, and watching it put pen to paper is still a little creepy today.

Below you’ll find a video from [Fran] demonstrating all seven drawings the Maillardet Automaton can reproduce. You can also find a whole bunch of pics of the mechanisms along with the 2007 repair report on [Andrew Baron]’s site.

Retrotechtacular is a weekly column featuring hacks, technology, and kitsch from ages of yore. Help keep it fresh by sending in your ideas for future installments.

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Retrotechtacular: Automata


For a moment, suspend your worldview and adopt Descartes’s mechanistic interpretation that living beings are essentially complex machines: a collection of inherently unrelated parts that move and collide. Automata, then, represented the pinnacle of accomplishment in a mechanistic universe, requiring considerable skill to construct. Most of their inventors, such as Pierre Jaquet-Droz, were clockmakers or watchmakers, and automata like the 240-year-old boy writer are packed with moving parts to automate motion.

Jaquet-Droz’s writer is particularly impressive considering all its moving parts—nearly six thousand of them—fit entirely within the boy’s body, and that one can “program” the text that the boy composes. It may sound like a bit of a stretch to claim that these clockwork amusements were precursors to the computer, but they influenced inventors and engineers for centuries.

You’ve likely heard of the other famous automaton: The Turk, (which was actually a hoax, housing an operator inside its base). The Turk, however, managed to inspire Charles Babbage to pursue building a mechanical device capable of performing mathematical functions: the Difference Engine.

Watch some of Jaquet-Droz’s other clockwork masterpieces in a video after the break. Magicians like Robert-Houdin were responsible for building a number of automata, so we recommend you keep the mystical atmosphere flowing by checking out another magician’s performance oddities.

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