Forming Sheet Metal Parts With 3D Printed Dies

March 10, 2020 by 27 Comments

Using 3D printed forms to bend sheet metal isn’t exactly new. We’ve seen several people create custom dies for their brakes, and the results have shown the concept has merit for small-scale production. But that’s usually where the process ends. A bend here or there is one thing, but the ability to form a complex shape with them has always seemed like asking too much. But judging by his recent experiments, [Shane Wighton] is very close to changing that perception.

The process at work here is, relatively speaking, pretty simple. You print out the upper and lower die, put a piece of sheet metal between them, and then smash them together with a hydraulic press. If everything works correctly, and your CAD skills hold true, the metal will take the desired shape.

Of course, that’s vastly oversimplifying things. As [Shane] explains in the video after the break, there are many nuances to forming sheet metal like this that need to be taken into account, and iteration and experimentation are basically unavoidable. So it’s a good thing you can rapidly redesign and reprint the dies.

Which isn’t to say that the dies themselves didn’t come with their own unique set of challenges. The first ones shattered under the pressure, and it took a few design revisions and eventually a switch to a stronger resin before [Shane] got a set of dies that could form the desired piece. Even still, he’s had a lot of trouble getting the printed parts to survive multiple uses. But he’s confident with some more refinements he could get a repeatable process going, and thinks ultimately producing runs of up to 100 parts on a set of printed dies isn’t out of the question.

Logically, it would seem plastic isn’t an ideal choice for punching and shaping metal. Frankly, it’s not. But if you’re doing in-house manufacturing, the ability to produce complex tooling quickly and easily can help make up for any downsides it might have.

Continue reading “Forming Sheet Metal Parts With 3D Printed Dies” →

EU Duty Changes, A Whole VAT Of Trouble For Hackers?

March 10, 2020 by 105 Comments

It could be said that there are a number of factors behind  the explosion of creativity in our community of hardware hackers over the last couple of decades, but one in particular that is beyond doubt is the ease with which it has been possible to import small orders from China. See something on AliExpress and it can be yours for a few quid, somewhere in a warehouse on the other side of the world it’s put into a grey shipping bag, and three weeks later it’s on your doorstep. This bounty has in no small part been aided by a favourable postage and taxation environment in which both low postage costs and a lack of customs duties on packages under a certain value conspire to render getting the product in front of you a fraction of the cost of buying the thing in the first place. Continue reading “EU Duty Changes, A Whole VAT Of Trouble For Hackers?” →

Bolts, Brass, And Machining Chops Make Up This Tiny Combination Safe

March 10, 2020 by 8 Comments

Another day, another video that seriously makes us doubt whether eschewing the purchase of a lathe in favor of feeding the family is a value proposition. This time, [Maker B] shows us what the queen of machine tools can do by turning a couple of bolts into a miniature safe.

We’ll state right up front that this build doesn’t source all its material from a single bolt. It’s more like two bolts and a few odd pieces of brass, but that doesn’t detract from the final product one bit. [Maker B] relieves the two chunky stainless steel bolts of their hex heads and their threads on the lathe, forming two nesting cylinders with a satisfyingly tight fit. A brass bar is machined into a key that fits between slots cut in the nesting cylinders, while discs of brass form the combination dials. Each disc is stamped around its circumference with the 26 letters of the alphabet; we thought the jig used for stamping was exceptionally clever, and resulted in neat impressions. The combination, which is set by placing a pin next to a letter in each disc, protects the admittedly limited contents of the tiny safe, but functionality is hardly the point. This is all about craftsmanship and machining skills, and we love it.

If you’ve sensed an uptick in resource-constrained builds like this lately, you’re not alone. The “one bolt challenge” has resulted in this wonderfully machined combination lock, as well as the artistry of this one-bolt sculpture. We’re all in favor of keeping the trend going. Continue reading “Bolts, Brass, And Machining Chops Make Up This Tiny Combination Safe” →

How To Get Into Cars: Handling Mods

March 10, 2020 by 31 Comments

As a budding automotive enthusiast, you finally took the plunge and scored yourself a sweet project car. After going through it from top to toe, you’ve done your basic maintenance and it’s now running like a top. Now you’re getting comfortable, you’ve set your sights on turning your humble ride into a corner carving machine. Here’s a guide to get yourself started.

It’s All About Grip

When it comes to creating a handling monster, the aim is to create a car that sticks to the road like glue, and is controllable when it does break loose. Having a car that handles predictably at the limit is a big help when you’re pushing hard on track, particularly for an inexperienced driver. And, whether you’re hitting the canyons on the weekend or trying to slash your laptimes, it’s always nice to have more grip. Through selecting the right parts and getting the set up right, it’s possible to hone your car’s cornering ability to make it a rewarding experience to drive fast and hard. Continue reading “How To Get Into Cars: Handling Mods” →

Solar Panel Keeps Car Battery Topped Off Through OBD-II Port

March 10, 2020 by 47 Comments

Up until the 1980s or so, a mechanic could check for shorts in a car’s electrical system by looking for sparks while removing the battery terminal with everything turned off in the car. That stopped being possible when cars started getting always-on devices, and as [Kerry Wong] learned, these phantom loads can leave one stranded with a dead battery at the airport after returning from a long trip.

[Kerry]’s solution is simple: a solar trickle charger. Such devices are readily available commercially, of course, and generally consist of a small photovoltaic array that sits on the dashboard and a plug for the lighter socket. But as [Kerry] points out in the video below, most newer model cars no longer have lighter sockets that are wired to work without the ignition being on. So he chose to connect his solar panel directly to the OBD-II port, the spec for which calls for an always-on, fused circuit connected directly to the positive terminal of the vehicle battery. He had to hack together an adapter for the panel’s lighter plug, the insides of which are more than a little scary, and for good measure, he added a Schottky diode to prevent battery discharge through the panel. Even the weak winter sun provides 150 mA or so of trickle charge, and [Kerry] can rest assured his ride will be ready at the end of his trip.

We used to seeing [Kerry] tear down test gear and analyze unusual devices, along with the odd post mortem on nearly catastrophic failures. We’re glad nothing burst into flames with this one.

Continue reading “Solar Panel Keeps Car Battery Topped Off Through OBD-II Port” →

The Best Voltage And Current Reference This Side Of A Test Lab

March 10, 2020 by 16 Comments

When you measure a voltage, how do you know that your measurement is correct? Because your multimeter says so, of course! But how can you trust your multimeter to give the right reading? Calibration of instruments is something we often trust blindly without really thinking about, but it’s not always an impossible task only for a high-end test lab. [Petteri Aimonen] had enough need for a calibrated current source to have designed his own, and he’s shared the resulting project for all to see.

The cost of a reference source goes up with the degree of accuracy required, and can stretch into the many millions of dollars if you are seeking the standards of a national metrology institute, but fortunately [Petteri]’s requirements were considerably more modest. 0.02% accuracy would suffice. An Analog Devices precision voltage reference driving a low-offset op-amp with a driver transistor supplies current to a 0.01% precision resistor, resulting in a reference current source fit for his needs. The reference is available in a range of voltages, his chosen 2.048 volts gave a 2.048 mA current sink with a 100 ohm resistor.

In a way it is a miracle of technology that the cheapest digital multimeter on the market can still have a surprisingly good level of calibration thanks to its on-chip bandgap voltage reference, but it never hurts to have a means to check your instruments. Some of us still rather like analogue multimeters, but beware — calibration at the cheaper end of that market can sometimes be lacking.

Divvy Out The Crypto With This Physical Bitcoin Faucet

March 9, 2020 by 3 Comments

For those unfamiliar with the term, a “Bitcoin Faucet” is usually used as an incentive in software that wants your attention. Complete a captcha or look at and advertisement and you get one millionth of a BTC, that sort of thing. You’re never going to get rich off of one of them, but most people aren’t going to turn down free money either. The latest project from [TJ Bruno] follows that same concept and brings it into the physical world. But you still aren’t going to get rich off of it.

The hardware used for this corporeal Bitcoin Faucet is pretty simple. All you need is a Raspberry Pi, a camera module, and a 2.8″ touch LCD. Naturally you could use a larger screen if you wanted, but then it wouldn’t fit inside of the very slick 3D printed stand that [TJ] developed. We might consider upgrading to a slightly speedier Pi though, in the demonstration video it looks like the Zero is struggling pretty hard to handle the GUI.

Using the Faucet is straightforward enough. You tap the screen and place a QR code representing your Bitcoin wallet on the device’s tray, where it’s scanned by the camera. In a few seconds the Faucet shows a QR code on its own screen that will point your phone’s browser to the transaction details so you can verify your digital coinage is on the way.

You might be wondering why you’d want to have a device that sits there waiting to pay out fractions of a BTC to anyone who’s willing to flash their wallet at it. We’re not entirely sure, though it might make for an interesting way to raise awareness about cryptocurrency. In this particular case though, [TJ] says he was just looking for a project that would give him an excuse to hone his Python skills. Nothing wrong with that around these parts.

Watching the growth of cryptocurrency from our unique vantage point, we can see how the hacker’s interest in Bitcoin as changed over the years. Where we once saw people excited about building custom mining rigs, we now see counters that tick down as the last coins are put into circulation. Looking at projects like this, it seems hackers are happy enough to just give the things away in an interesting way.