How To Get Good With Wood

September 6, 2021 by Tom Nardi 6 Comments

It’s perhaps unsurprising that we don’t see much in the way of woodworking here at Hackaday; after all, this is a plastics and metal community if there ever was one. But that doesn’t mean you’ll never come across a situation where a dead tree needs to be cut or shaped to your will, so we appreciate [Eric Strebel] demonstrating some tips and best practices for working with this exceptionally versatile building material.

The first video assumes you’re a lumber neophyte, and goes over topics such as the different species of wood you’re likely to find at the hobby shop, proper sanding technique, and the differences between cutting with and against the grain. Some of the different cutting tools you can use are also covered, ranging from the humble hobby knife to the band saw. As always, [Eric] sprinkles the video with tips and tricks gained from his considerable professional experience, such as using some glue and a bit of sawdust to fill in any gaps left behind by an uneven joint.

In the second video, things start getting more advanced. [Eric] demonstrates how you can create custom laminates, and how wood can be permanently bent into arbitrary shapes with sufficient steam and clamping pressure. By combining these new techniques with the basic concepts covered in the first video, surprisingly complex shapes can be formed with minimal effort.

[Eric] previously put together a similar series of videos on working with acrylic, a material that’s arguably far more familiar to the Hackaday readership. But whatever material you use, the takeaway message from this series is clear: get the right tools, learn the techniques, and professional results are well within your reach.

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See The Unseen With This Magnetic Field Visualizer

September 1, 2021 by Tom Nardi 8 Comments

The average Hackaday reader likely knows, at least in the academic sense, what a magnetic field looks like. But as the gelatinous orbs in our skull can perceive only a tiny fraction of the EM spectrum, we have to take those textbook diagrams at face value. That is, unless you’ve got one of these nifty magnetic field visualizers developed by [Dr.Stone].

Using an XMC1100 microcontroller development board and a TLV49 3D magnetic sensor, the device is able to track the poles of a magnet in real-time and produce an approximation of what the field lines would look like on its electronic paper display. Relative field strength is indicated by the size of the visualization, which allows the user to easily compare multiple magnets. Incidentally, [Dr.Stone] notes that the current version of the hardware and software can only handle one magnet at a time; visualizing complex magnetic fields and more than two poles would take an array of sensors and likely a more powerful processor.

Do you need to visualize the field lines around a magnet? Perhaps not. But being able to quickly get an idea of how strong a magnet is and identify where its poles are could certainly come in handy. We’d like to see [Dr.Stone] take the project to the next phase and turn this into a handheld device for convenient workbench use. It would be a lot less messy than some of the previous methods we’ve seen for visualizing magnetic fields, though if you’re only worried about field strength, there’s arguably more straightforward ways to display it.

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Better 3D Scans Through A Slowed Down Turntable

August 31, 2021 by Tom Nardi 6 Comments

3D scanners aren’t cheap, and the last thing you want to see after purchasing one is bad data. But that’s what [Dave Does] and others were getting from their Revopoint POP scanners until some communal brainstorming uncovered the reason: the motorized turntable that came with the Kickstarter edition of the product was spinning too fast for the software to accurately keep track of the object. So he decided to replace the stepper motor controller in his turntable and document the process for anyone else who’s scanner might be struggling.

In the video below, [Dave] pops open the plastic case of the turntable and reveals a pretty sparse interior. There’s an incredible amount of empty space inside, and even some mounting studs to screw down new components, should you want to get into some hardcore upgrades. But for his purposes, a generic stepper motor controller that featured a potentiometer to adjust the speed was enough. He found a suitable board online for around $5 USD, and got to designing a 3D printed bracket that mates up to the existing screw holes on the turntable.

But it’s not exactly a drop-in replacement. For one thing, you’ve got to pop a hole in the side of the enclosure for the potentiometer knob to stick out of. You’ve also got to solder wires coming from the original DC jack and power switch to the new board to get it hooked up, but at least the motor plugs right in. In the video below, you can see [Dave] demonstrate the impressively deep throttle capability of the new driver.

If you’d rather build than buy, we’ve covered some impressive DIY turntables in the past that could fit the bill nicely, from automatic models that handle camera control to fully 3D printed versions that you’ve got to crank yourself.

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Impromptu Metal Detector Built From The Junk Bin

August 30, 2021 by Tom Nardi 12 Comments

Have you ever found yourself suddenly in need of finding a small metal object hidden in the woods? No? Well, neither have we. But we can’t say the same thing for [zaphod], who’s family was hoping to settle a dispute by finding the surveyor stakes that marked the corners of their property. It was a perfect job for a metal detector, but since they didn’t own one, a serviceable unit had to be assembled from literal garbage.

To start with, [zaphod] had to research how a metal detector actually works. After reviewing the pros and cons of various approaches, the decision was made to go with a beat frequency oscillator (BFO) circuit. It’s not the greatest design, it might even be the worst, but it could be built with the parts on hand and sometimes that’s all that matters. After packing a 2N3904 transistor, an LM386 amplifier, and every Hackaday reader’s favorite chip the 555 timer into an enclosure along with some of their closest friends, it was time to build the rest of the metal detector.

The sensor coil was made by salvaging the wire from an old fluorescent lamp ballast and winding it around the lid of a bucket 27 times. This was mounted to the end of a broom handle with some angle pieces made from PVC sheet material, being careful not to use any metal fasteners that would throw off the detector. With the handle of an old drill in the middle to hold onto, the metal detector was complete and actually looked the part.

So did [zaphod] save the day by finding the surveyor stakes and reconnoitering the family’s plot? Unfortunately, no. It wasn’t a technical failure though; the metal detector did appear to work, although it took a pretty sizable object to set it off. The real problem was that, after looking more closely into it, the surveyors only put down one stake unless they are specifically instructed otherwise. Since they already knew where that one was…

If your homemade metal detector can’t find something that was never there, did it really fail? Just a little something to meditate on. In any event, when even the cheapest smart bulb is packing a microcontroller powerful enough to emulate early home computers, we’re always happy to see somebody keep the old ways alive with a handful of ICs.

Custom Soldering Fume Fan Doesn’t Skimp On Features

August 27, 2021 by Tom Nardi 8 Comments

Prolific maker [sjm4306] tells us the first iteration of his soldering fan was little more than some cardboard, electrical tape, and a hacked up USB cable. But as we all know, these little projects have a way of evolving over time. Fast forward to today, and his custom fan is a well-polished piece of kit that anyone with a soldering iron would be proud to have on their workbench.

Cardboard has given way to a 3D printed enclosure that holds the fan, electronics, a pair of 18650 cells, and a easily replaceable filter. Between the marbled filament, debossed logo, properly countersunk screw holes, and rounded corners, it’s really hard to overstate how good this case looks. We’ve shamefully produced enough boxy 3D printed enclosures to know that adding all those little details takes time, but the end result really speaks for itself.

Fan internals, with a look at the custom PCB.

The user interface running on the OLED is also an exceptionally nice touch. Sure the fan doesn’t need a graphical display, and [sjm4306] could have saved a lot of time and effort by using a turn-key speed controller, but the push-button configuration complete with graphical indications of fan speed and battery life really give the final product a highly professional feel.

In the video below, [sjm4306] reveals that while the finished product might look great, there were a few bumps in the road. Issues with clearance inside the case made him rethink how things would be wired and mounted, leading to a far more cramped arrangement than he’d anticipated. Part of the problem was that he designed the case first and tried to integrate the electronics later, rather than the other way around; a common pitfall you’d be wise to watch out for.

It’s been proven that, without some external input, solder smoke is going to go right in your face. Whether or not you need to do something this complex is naturally up for debate, but if you want to keep all that nasty stuff out of your lungs, you’d do well to outfit your workbench with some kind of fan.

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Making High Quality Copies Of Existing Parts Using A Silicone Mold

August 26, 2021 by Danie Conradie 4 Comments

3D printing has made it incredibly easy to produce small runs of plastic parts, but getting rid of the 3D printed look can be tricky and time-consuming. When you need a smooth and polished finish, or you want to make exact copies of an existing injection molded part, casting resin parts in silicone molds is an excellent option. [Eric Strebel] has plenty of experience with the process, and demonstrates it in detail while creating copies of violin chin rests that are no longer in production. It’s an interesting application, where 3D-printed layer lines are not just an aesthetic issue, but something that would irritate the user’s skin if present.

Creating silicone molds requires a bit of forethought about the mold design. You want to select the split line to make it as easy as possible to remove the finished parts, while also placing the resin pouring sprue and vents to prevent air bubbles from getting trapped in the mold. In [Erics] case, it’s impossible to use a simple planar split line, so he mounts the master part on a block of wood and uses cardboard and modeling clay to create a volume where the second side of the mold will protrude in the first side. It’s important to note that sulfur-free clay must be used, otherwise the silicone might not cure.

One side of the silicon mold is cast first, and after curing it is placed back in the mold box with the master part to allow casting the other side of the mold. At this point [Eric] super glues the sprue-former and vent rods to the master parts before molding the second side. A release agent consisting of petroleum jelly and naphtha is added wherever the two sides of the mold will touch, to prevent them from sticking together.

Bubbles are your enemy while resin casting, so ideally you need a vacuum chamber to degas the silicone and resin before casting, and a pressure chamber to allow the resin part to cure. While pouring the silicone for the molds, the mold box is placed on a vibration table to allow any bubbles to rise to the surface. While the entire mold-making and molding process is time-consuming, the copied parts are almost indistinguishable from the original.

[Eric] has also shown us how to make much larger silicone molds in the past. If you find yourself making lots of different-sized mold boxes, it might be worth building an adjustable mold box.

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Automatic Nut Sorter For A Tidy Workspace

August 23, 2021 by Al Williams 28 Comments

We all have that one drawer or box full of random hardware. You don’t want to get rid of anything because as soon as you do, that’s the one thing you’ll need. But, honestly, you’ll be lucky to find what you need in there, anyway. Enter [Mr. Innovative’s] nut sorting machine. As you can see in the video below, it will make order out of the chaos, at least for nuts.

You might think the device would need optical recognition software or some other high-tech mechanism. But, in fact, it is nothing more than a motor with a speed controller. The sorting is done by a plastic piece built like stairs. When a nut is too tall to fit under the next step, it slides out into the output hopper. You could probably turn the whole thing with a crank and no electricity at all if you wanted to.

Drilling out the shaft required a bit of machine tool usage, so this might not be a great weekend project without a lathe. Like many of the commenters on the video mentioned, we probably wouldn’t have used a rod holder as a rotating bearing, either, but for as little as something like this would probably operate, it is likely to last a fair amount of time. It would be easy to replace it or even affix a shaft to the motor with a coupler, sidestepping several issues.

Apparently, the device isn’t perfect. You do get some missorts. We imagine that’s from a larger nut pushing a smaller nut on the way to the hopper. The Thingiverse files seem to be missing, but this is something you’d probably adapt to your own design, anyway.

It isn’t as automated, but we’ve seen a gadget that can help sort drill bits, too. Sometimes you want to sort little parts by color, too.

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