DIY Watertight Junction Box For Serious Outdoor Sealing

September 10, 2019 by Donald Papp 32 Comments

Thingiverse user [The-Mechanic] shared a design for 3D printed enclosures that are made to house wire and cable junctions, which can then be rendered weatherproof by injecting them with a suitable caulking compound and allowing it to cure. It’s a cross between an enclosure and potted electronics. It’s also a one-way trip, because the result is sealed up like a pharaoh’s tomb. On the upside, it’s cheap, accessible, and easily customized.

The way it works is this: wires go through end caps which snap onto the main body, holding the junction inside. Sealant is then pumped in via the hole on the side, then the hole is plugged. Afterwards, all there is to do is wait until the sealant cures. [The-Mechanic] has a couple of companion designs, as well. For tubes of sealant that have threaded tops, one can more effectively save the contents of the tube for later with this design for screw-on caps. There are also 3D printed nozzles in a variety of designs.

One thing to keep in mind about silicone-based sealants is that thick gobs of it can take a really, really long time to cure fully. A thick gob of the stuff will tend to firm up on the outside but leave the inside gooey. If that will be a problem, maybe take a cue from Oogoo and mix in a bit of corn starch with the silicone sealant. The resulting mixture will be thicker, but it’ll cure throughout with no problems.

Cheese Grater Now Grates Cheese

September 9, 2019 by Bryan Cockfield 11 Comments

If you’ve been using Apple products since before they were cool, you might remember the Power Mac G5. This was a time before Apple was using Intel processors, so compatibility issues were high and Apple’s number of users was pretty low. They were still popular in some areas but didn’t have the wide appeal they have now. The high quality of the drilled aluminum design lived on into the Intel era and gained more popularity, but the case was still colloquially known as the “Cheese Grater”. Despite not originally being able to grate cheese though, this Power Mac actually does grate cheese.

Ungrated cheese is placed in the CD drive slot where it passes through a series of 3D printed gears which grate the cheese into small chunks. The cheese grating drive is automatically started when it detects cheese via a Raspberry Pi. The Pi 4 also functions as a working desktop computer within the old G5 case, complete with custom-built I/O ports for HDMI that integrate with the case to make it look like original hardware.

Funnily enough, the Pi 4 has more computing power and memory than Apple’s flagship Mac at the time, and consumes about 100 times less power. It’s a functional build that elaborates on an in-joke in the hardware community, which we can all appreciate. Perhaps the next build should be something that uses the blue smoke for a productive purpose. Meanwhile, regular readers will remember that this isn’t the first Apple related cheese grating episode we’ve shown you.

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One-Motor Domino Laying Machine Works For Tips

September 9, 2019 by Donald Papp 21 Comments

[Gzumwalt] did things a little differently with his Pink and Green Domino Machine II, a 3D printed device that drops dominoes in a neat row ready for toppling over. Unlike his earlier version, this one holds dominoes laying flat in a hopper that’s accessible from the top for easy loading. The previous unit had an elegance to it, but it was more limited with respect to how many dominoes it could hold at a time. This new version solves that problem while also showing off a slick mechanism that gracefully slides a domino from the bottom of the hopper, then gently positions it standing on end before opening a rear door to let it out as it moves to the next position. One of the interesting things [gzumwalt] discovered when designing this device was that there isn’t really a “standard” size of domino. That’s one of the reasons the demo uses 3D printed blocks.

Pulling this off with a single small DC motor is a remarkable achievement; the mechanism even stably ejects a positioned domino from the rear without halting its forward motion in the process. An animation of how the mechanism works is embedded below, be sure to check it out!

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You Didn’t See Graphite Around This Geiger Counter

September 8, 2019 by Bryan Cockfield 19 Comments

Even if you don’t work in a nuclear power plant, you might still want to use a Geiger counter simply out of curiosity. It turns out that there are a lot of things around which emit ionizing radiation naturally, for example granite, the sun, or bananas. If you’ve ever wondered about any of these objects, or just the space you live in, it turns out that putting together a simple Geiger counter is pretty straightforward as [Alex] shows us.

The core of the Geiger counter is the tube that detects the radiation. That’s not something you’ll be able to make on your own (probably) but once you have it the rest of the build comes together quickly. A few circuit boards to provide the tube with the high voltage it needs, a power source, and a 3D printed case make this Geiger counter look like it was ordered from a Fluke catalog.

The project isn’t quite finished ([Alex] is still waiting on a BNC connector to arrive) but seems to work great and isn’t too complicated to put together, as far as Geiger counters go. He did use a lathe for some parts which not everyone will have on hand, but a quick trip to a makerspace or machinist will get you that part too. We’ve seen some other parts bin Geiger counters too, so there’s always a way around things like this.

Putting 3D Printed Speaker Drivers To The Test

September 7, 2019 by Tom Nardi 15 Comments

Over the years, we’ve seen numerous projects that attempted to 3D print speaker enclosures that deliver not only a bit of custom flair, but hopefully halfway decent sound. Though as you’d probably expect, the drivers themselves are always standard run-of-the mill hardware mounted into the plastic enclosure. But given the research being conducted by [Paul Ellis], that might not be a safe assumption for much longer.

His quest to develop a full-range 3D speaker has taken him through several design revisions over the last two years, with each one being put through testing procedure that compared its frequency response to “real” speakers from manufacturers like Dayton and Bose. The project is very much ongoing, but a recently completed iteration of the driver design managed to exceed 80 dB at 1 W. In terms of audio quality, [Paul] reports they can hold their own against commercially available drivers. You can hear for yourself in the video after the break.

Ultimately, he hopes to be able to sell his 3D printed speakers in kit form to anyone who’s looking for the last word in bespoke audio hardware. The idea being that the drivers and enclosure will be completely modular, allowing the user to swap out individual components for ones printed (or not) in different materials so they can tune the in-person sound to their exact specifications. To facilitate this rapid reconfiguring of the drivers, the designs use some neat tricks like having the magnets be removable rather than glued in so they could be swapped out non-destructively.

This isn’t the first fully 3D printed speaker driver we’ve ever seen, Formlabs showed one off that was made on their SLA printer back in 2015, and we actually saw a rudimentary take on the same idea earlier this year. But the work that [Paul] has done here is certainly the most thorough, and dare we say practical, take we’ve ever seen on the concept.

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Print A Drill Press For Your Printed Circuit Boards

September 5, 2019 by Ted Yapo 14 Comments

If you make printed circuit boards the old fashioned way by etching them yourself, you may need to drill a lot of holes; even surface-mount converts still need header pins on occasion. But, drilling these holes by hand often leads to broken drill bits, which always seems to happen with one un-drilled hole and no spare bits left. [Daumemo] came up with a solution: a 3D printed drill press for a Dremel or similar rotary tool.

While you can buy commercial presses designed to fit these tools, there’s a certain satisfaction to building your own, and if you have a well-stocked parts bin you might even finish it before a mail-ordered version could arrive. Certainly you could do it at lower cost. The design is straightforward, and uses printed parts augmented with “reprap vitamins” (i.e. the non-printable, typically metal, components). If you’ve ever built — or repaired — a 3D printer, you may have these pieces already: a couple of LM8UU bearings, some 8 mm steel rod, and a pair of springs seem like the most esoteric parts required, although even these could probably be substituted without much trouble.

Only a few pieces need to be printed: a base is outfitted with a removable table for holding the workpiece, while a lever actuates the frame holding the tool. [Daumemo] chose to print the design in ABS, but found that it flexes a little too much, occasionally requiring some care during use — a stiffer filament such as PLA might yield better results. Overall, though, this seems like a great project for that 3D printer you haven’t used in a while.

Be sure to check out the video of the press in action, after the break.

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A Teeny Tiny 3D Printed Macro Extension Tube

September 4, 2019 by Tom Nardi 10 Comments

When you hear the term “extension tube”, you probably think of something fairly long, right? But when [Loudifier] needed an extension tube to do extreme close-ups with a wide-angle lens on a Canon EF-M camera, it needed to be small…really small. The final 3D printed extension provides an adjustable length between 0 and 10 millimeters.

But it’s not just an extension tube, that would be too easy. According to [Loudifier], the ideal extension distance would be somewhere around 3 mm, but unfortunately the mounting bayonet for an EF-M lens is a little over 5 mm. To get around this, the extension tube also adapts to an EF/EF-S lens, which has a shorter mount and allows bringing it in closer than would be physically possible under otherwise.

[Loudifier] says the addition of electrical connections between the camera and the lens (for functions like auto focus) would be ideal, but the logistics of pulling that off are a bit daunting. For now, the most reasonable upgrades on the horizon are the addition of some colored dots on the outside to help align the camera, adapter, and lens. As the STLs and Fusion design file are released under the Creative Commons, perhaps the community will even take on the challenge of adapting it to other lens types.

For the polar opposite of this project, check out the 300 mm long 3D printed extension tube we covered a few weeks back that inspired [Loudifier] to send this project our way.