Clicky Signspinner Works Just Like A Retractable Pen

[u407]’s 3D printed Signspinner was created as a clean/dirty indicator for a dishwasher, and at its heart is a mechanism that works a lot like that of a retractable ballpoint pen. Every click of the plunger spins the circular label inside by one-quarter of a rotation. In [u407]’s case it only needs to alternate between showing “clean” and “dirty”, but there are in fact four total label positions.

The entire mechanism including the spring is 3D printed, but the spring is PETG and the rest is PLA. [u407] doubts PLA would work for the spring because of how much it gets compressed, but suggests that ABS might work as an alternative.

If you’re having trouble visualizing how this mechanism works, we covered [Bill Hammack] explaining exactly how retractable ballpoint pens work which should make it perfectly clear. It’s fundamentally the same principle.

[via Reddit]

3D Printed Fan Filter Takes Cues From Costume Scene

This custom fan filter created by [Kolomanschell] is a clever application of a technique used to create wearable 3D printed “fabrics”, which consist of printed objects embedded into a fine mesh like a nylon weave. The procedure itself is unchanged, but in this case it’s done not to embed 3D printed objects into a mesh, but to embed a mesh into a 3D printed object.

The basic idea is that a 3D print is started, then paused after a few layers. A fine fabric mesh (like tulle, commonly used for bridal veils) is then stretched taut across the print bed, and printing is resumed. If all goes well, the result is 3D printed elements embedded into a flexible, wearable sheet.

The beauty of this technique is that the 3D printer doesn’t need to be told a thing, because other than a pause and resume, the 3D print is nothing out of the ordinary. You don’t need to be shy about turning up the speed or layer height settings either, making this a relatively quick print. Cheap and accessible, this technique has gotten some traction in the costume and cosplay scene.

As [Kolomanschell] shows, the concept works great for creating bespoke filters, and the final result looks very professional. Don’t let the lack of a 3D model for your particular fan stop you from trying it for yourself, we’ve already shared a great resource for customizable fan covers. So if you’ve got a 3D printer and a bit of tulle, you have everything you need for a quick afternoon project.

Enclosure Needs Labels? Make The 3D Printer Do It

Tool changing on 3D printers is hot right now, and it’s going to be really interesting to see the ideas that reliable tool changing lets people try out. One such idea is having the 3D printer use a marker to label the enclosure and buttons it just 3D printed.

The 3D print shown is an enclosure for a Pocket Operator by Teenage Engineering. [Marc Schömann] made the enclosure on Blackbox, a tool-changing 3D printer that he designed. The video below shows a pen holder drawing the labels directly onto the printed object. Pocket Operators may look like calculators, but they are clever electronic musical devices capable of producing real music. (The best way to learn about what they are and what they can do is to watch a tutorial video or two.)

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3D Printed Buttons, Printed As A Single Unit

These nifty buttons come from [Marc Schömann], and they are intended to cover just about any kind of tact switches. The buttons, their cover, and the compliant bits that act as a spring can be 3D printed as a complete unit that requires no assembly, and can be used fresh off the print bed.

The design is still being developed, but those interested in playing with it can download the current model here. [Marc] printed this version in two colors, but that’s just to make how the buttons work easier to see. It also gave him an opportunity to test and tune the tool changer on his printer.

Tool changer, you say? Yes, indeed. The printer is the Blackbox, a open source, tool-changing 3D printer of [Marc]’s own design with its own Hackaday.io project page.

Embedded below is a video overview of the button design being prepped and printed on a Blackbox printer, with a tool change happening in the process. Tool changing is an attractive feature that many people including E3D have taken a swing at, and it’s always exciting to see it in action.

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How Not To Get Paid For Open Source Work

[Avi Press] recently made a Medium post sharing his thoughts on a failed effort to allow for paid users of an open source project. [Avi] is the author of Toodles, a tool to help organize and manage TODO items in software development. Toodles enjoyed unexpected popularity, and some of its users were large organizations. It seemed that Toodles was of value to people who could afford to pay, and they might even be willing to do so if [Avi] provided a way for them to do it. It turned out that the monetizing process was far from simple, and he ultimately wasn’t successful.

Before he even started, [Avi] thought carefully about things and found that even basic and preliminary questions were difficult to answer, such as:

  • How many people were actually using the software on a regular basis? Were they gaining quantifiable value from it?
  • What exactly would someone be buying? How would they pay, and how would it get delivered to them?
  • How could companies be charged for the tool while still offering it freely to individuals?
  • Is it even ethical to accept money for a project to which others have contributed? How could money be shared with contributors? How to fairly decide who gets how much?

In short, [Avi] discovered that much of the data he felt he needed in order to make these decisions didn’t exist, wasn’t easily accessible, or couldn’t be reliably measured. His experiment in adding a license and payment system (which always seemed to need more work than it should) yielded no fruit, as there were zero paid users anyway.

Regardless of whether “difficulty in shoehorning a paid license system into an open source project” should be filed under “Feature, not Bug” [Avi] does thoughtfully present the issues he encountered. Open source and getting paid are not necessarily mutually exclusive. Octoprint is one example of an open source project that eventually navigated these waters, but that doesn’t mean it was easy, nor does it mean there are established tools and processes.

E-Book Reader Gets Page Turn Buttons, Is None The Wiser

Most e-book readers don’t have physical page turn buttons. Why? They just don’t. Virtual page turns are accomplished with a tap at a screen edge. Determined to reduce the awkwardness of one-handed use, [Sagar Vaze] modified a Kobo e-reader with two physical page turn buttons as a weekend project.

[Sagar] points out that since the underlying OS of the Kobo device is Linux, it is possible to fake touches to the screen (and therefore trigger page turns) by recording then replaying the appropriate input event. However, there was a more direct solution available to those willing to tamper slightly with the hardware. Touch sensing on the screen is done via an infrared break-beam system. Along two edges of the screen are IR emitters, and opposite the emitters are receivers. Broadly speaking, when a fingertip touches the display a minimum of two IR beams are broken, and the physical location of the fingertip can therefore be determined by analyzing exactly how the IR pattern has been changed.

To spoof page turns, [Sagar] briefly shorts two IR emitters: one on each axis. The sudden winking out of the IR is interpreted by the device as a crisp tap, and the device obediently turns the page. The only hitch is that both IR emitters must be shorted at the same time. If one is shorted before the other, the device ignores it. Double-pole switches would probably do the trick, but with the part bin coming up empty in that respect, [Sagar] instead used a few transistors to accomplish the same thing. A 3D printed enclosure rounds out the whole mod, and a brief video is embedded below.

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Bit Preserve: A Sanctuary For Modern Captures Of Vintage Schematics

Vintage parts may be documented, but that doesn’t mean they’re particularly useful or accessible. If the phrase “eyestrain from unsearchable, badly-scanned PDF datasheets” makes your lower eyelid twitch in sympathy, read on.

While [Bald Engineer] was researching how he might make a portable Apple II, he was delighted to find that the vintage components he needed to examine were documented. However, he became frustrated with the seemingly endless number of poor quality PDF scans and the inability to search effectively. He decided to re-create the entire Apple IIgs schematic in KiCad, and in the process the Bit Preserve project was born. The goal is to act as a safe haven for modern and editable versions of vintage electronic schematics. The GitHub repository can be found here.

[Bald Engineer] talks a bit about his Apple II project, as well as the ideas behind the Bit Preserve project in his KiCon 2019 talk “Preserving History with KiCad”. KiCon was wild, and we have loads of photos of the projects and details so be sure to check it out.