Parts

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An Open Source Modular Flexure Construction Set

November 22, 2022 by 14 Comments

Flexures are one of those innocent-looking mechanisms that one finds inside practically any kind of consumer device. Providing constrained movements with small displacements, complete with controlled tension, they can be rather tricky to design. GrabCAD designer [Vyacheslav Popov] hails from Ukraine, and due to the current situation there, plans to sell a collection of flexure building blocks became difficult. In the end, [Vyacheslav] decided to generously release his work open source, for all to enjoy. This collection is quite extensive, looking like it could solve a huge variety of flexure design problems. (Links to the first three sets: Set00, Set01, Set02 but check the author’s collection page for many others)

It’s not just those super-cheap mechanisms in throw-away gadgets that leverage flexures, it’s much more. The Mars rovers use flexure-based suspension, scientific instruments (interferometers and the like) make use of them for small motions where specific axis constraints are needed, and finally, MEMS accelerometers and gyroscopes are based entirely upon them. We’re not even going to try to name examples of flexures in the natural world. They’re everywhere. And, now we’ve got some more design examples to use, so why not flex your flexure muscles and send one to the 3D printer and have a play?

We see flexures here quite a bit, like this nice demonstration of achievable accuracy. Flexures can make some delicious mechanisms, and neat 3D printable input devices.

Thanks to [Addison] for the tip!

New Part Day: The Smallest Batteries You Have Ever Seen

November 15, 2022 by 18 Comments

We’re used to some pretty small batteries in miniaturized electronics, thanks to the manufacture of lithium-polymer pouch cells. But they’re still pretty big, and they’re hardly the most stable power storage solution. The French company ITEN may have an answer for designers of micro-power devices though, in the form of a range of tiny surface-mount solid-state rechargeable lithium batteries. These come in a range of capacities from 0.1 mAh to 0.5 mAh, and in a 3.2 by 2.5 mm package look very much like any other slightly larger SMD chip component.

These devices are most likely to be found in applications such as remote wireless sensors, where they can store the energy from a small solar cell or similar to produce the burst of power required to transmit a packet of data as well as the tiny current required to keep things ticking over. The solid state chemistry should provide a long life and lack of leaks. For now they have some evaluation kits on offer, and unless we missed something, no full data sheet. We’d be particularly interested to learn about their temperature sensitivity when it comes to soldering, as we’ve taken to heart the  warnings about soldering to more traditional lithium cells.

Via CNX Software.

Several shelf boxes of various widths are held together by brightly-colored plus-sign-shaped connectors.

3D Printed Shelf Connector

November 8, 2022 by 15 Comments

Sometimes, you really need a custom shelf. Whether you have a weird-shaped space, weird-shaped stuff, or just want something different, making your own shelving can make your place more like home. The Plus Shelf by [shurly] aims to make building your own shelves a little easier with a 3D printed bracket.

These connectors aren’t just sitting flush against the wood of the shelf. Each end of the + sign actually sits in a 3/8″ drilled recess, giving a more secure fit. The pieces were printed on an Objet and then dyed in various bright shades to really make the shelving pop. The cubbies were assembled with biscuits after cutting down a sheet of plywood to the appropriate sizes. The 45˚ angles around the edges of the cubbies make the whole shelf system that much nicer.

The final shelf has a little wobble, but that’s probably because dying the shelf connectors made them “bendy.” Because of the instability with the friction fit, the shelf connectors were super glued into the shelf boxes. [shurly] hopes that a metal version of the connectors might be able to eliminate these problems in the future.

This shelving system not your cup of tea? Maybe you’d prefer this Vintage Adjustable Shelving Method or this MP3 Player Shelf.

When Only A TO92 Will Do

November 5, 2022 by 17 Comments

As through-hole components are supplanted by their surface-mount equivalents, we’re beginning to see the departure of once-common component form factors. Many such as the metal can transistors became rare years ago, while others still hang on albeit in fewer and fewer places. One of these is the once-ubiquitous TO92 moulded plastic transistor, which we don’t see very much of at all in 2022. [Sam Ettinger] is a fan of the D-shaped plastic blobs, and has gone as far as to recreate them for a new generation to enjoy.

Though a TO92 was a relatively miniature package in its day, it’s still large enough to easily fit a SOT23 or similar SMD packaged device on a small PCB. So the tiny board with just enough space for the part and the three wires was fabricated, ready for encapsulating. Epoxy moulding a TO92 gave very poor results, so instead an SLA print of a T092 shell was made. It fits neatly over the PCB, producing a perfect TO92 package. We’re sure a translucent pink package would have raised a few eyebrows back in the 1960s though.

There will come a time when restorers of old electronics will use and refine this technique to replace dead components. We’ve seen the technique before, after all.

Scripting Coils For PCB Motors

October 25, 2022 by 12 Comments

PCB inductors are a subject that has appeared here at Hackaday many times, perhaps most notably in the electromagnetic exploits of [Carl Bugeja]. But there is still much to be learned in the creation of the inductors themselves, and [atomic14] has recently been investigating their automatic creation through scripting.

A simple spiral trace is easy enough to create, but when for example creating a circular array of coils for an electric motor there’s a need for more complex shapes. Drawing a trapezoidal spiral is a surprisingly difficult task for a script, and we’re treated to a variety of algorithms in the path to achieving a usable design.

Having perfected the algorithm, how to bring it into KiCAD?  The PCB CAD package has its own Python environment built-in, but it’s not the most flexible in which to develop. The solution is to write a simple JSON interpreter in KiCAD, and leave the spiral generation to an external script that passes a JSON. This also leaves the possibility of using the same code in other PCB packages.

You can watch the whole video below the break. Meanwhile for more PCB electromagnetics, watch [Carl Bugeja]’s 2019 Supercon interview.

Continue reading “Scripting Coils For PCB Motors” →

3D Printed Sorter Separates Spare Hex Nuts With A Shake

October 13, 2022 by 14 Comments

Got a pile of mixed hex nuts? Sort them in no time by printing [jonafriendj]’s nut sorter, which has options for pretty much any nut size you’d be after (it’s labeled metric, but actually includes Imperial sizes as well.)

Something to admire about the design is the handy little raised labels on each of the sieves, and the fact that all the parts print entirely without supports. Designing a part to play to a manufacturing method’s strengths (and avoid its weaknesses) is good DFM, or Design for Manufacturing.

With 3D printing being the boon that it is to workshops and hobbyists everywhere, it certainly pays to strive for good DFM, especially for designs meant to be shared with others. Sometimes good DFM takes a page from other manufacturing methods like injection molding, and we end up with things like using crush ribs on printed parts.

Want to see a demonstration of [jonafriendj]’s nut sorting design? Check out the short video embedded below the page break. If that leaves you wanting, take a look at a motorized, automated DIY solution.

Continue reading “3D Printed Sorter Separates Spare Hex Nuts With A Shake” →

A tiny CRT showing an eye, inside a plexiglass enclosure

This Eye Is Watching You From Its Tiny CRT

October 9, 2022 by 25 Comments

The days of cathode ray tubes, or CRTs, are firmly behind us, and that’s generally a good thing. Display tubes were heavy, bulky and fragile, and needed complicated high-voltage electronics in order to work. But not all of them were actually large: miniature display tubes were also produced, for things like camcorder viewfinders, and [Tavis] from Sideburn Studios decided to turn one of those into a slightly creepy art project.

The heart of this build is a one-inch CRT that was salvaged from an RCA video camera. [Tavis] mounted the tiny tube inside an acrylic box on a 3D printed base. Inside that base sits a Raspberry Pi along with a high-voltage driver and a power management board. The Pi continuously plays a video that shows a human eye blinking and looking in various directions. Just an eye, floating in space, looking at the world around it.

The magic is briefly lost when the Pi starts up, because it then shows a microscopic version of the Pi’s standard bootup sequence, but once the thing is running it adds a weird vibe to a room. It actually looks like something you’d find in an avant-garde art exhibition — in the video (embedded below) it’s accompanied by eerie music that gives it an even more unsettling feel. Electronic eyes are always a bit scary, especially when they’re actually looking at you.

Continue reading “This Eye Is Watching You From Its Tiny CRT” →