Make A Non-Contact Voltage Probe

April 1, 2019 by Al Williams 10 Comments

You’ve probably seen probes that detect live wires in, for example, home wiring, without having to actually probe the wire. These are sometimes used to test strings of Christmas lights, too. We’ve even seen the sensors built into a voltmeter. [Crazy Couple] has a few do-it-yourself versions that can do the job. You can see the circuits in the video below.

A contactless probe picks up the changing magnetic field around an unshielded wire with an AC voltage on it. Current doesn’t have to be flowing since it picks up the voltage (for example, you can detect voltage on a switch that is turned off or a Christmas tree light that is burned out. There are several different circuits using chips ranging from a CMOS IC to a 555. There’s also a version with three bipolar transistors.

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Build Your Own Metal Roller

March 31, 2019 by Zoe Skyforest 26 Comments

Metal fabrication is a useful skill to have. There’s plenty you can achieve in your workshop at home, given the right tools. There’s lathes for turning, mills for milling, and bandsaws and dropsaws for chopping it all to pieces. But what do you do if you need to make hoops and bends and round sections? You build a metal roller, of course – and that’s precisely what [James Bruton] did.

The main body of the tool is built out of box section, chosen largely as it’s what [James] had lying around. Bearings are of the familiar pillow block variety, with 20 mm bright steel serving as the rollers due to its better tolerance than mild steel stock. Set screws hold the shafts in place to avoid everything sliding around the place. A 10-ton bottle jack then provides the force to gently bend the workpiece as it passes through the rollers.

Initial tests were positive, with the roller producing smooth curves in 4 mm thick steel bar. There were some issues with runout, which were easily fixed with some attention to the parallelism of the shafts. It’s a tidy build, and can serve as a basis for further upgrades in future if necessary.

We’ve seen DIY roll benders before, too. Video after the break.

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Grab An Image From Your O-scope The Easy Way

March 30, 2019 by Brian Benchoff 34 Comments

The Rigol DS1054Zed is the oscilloscope you want. If you don’t have an oscilloscope, this is the scope that has the power and features you need, it’s cheap, and the people who do hardware hacks already have one. That means there’s a wealth of hardware hacks for this oscilloscope. One small problem with the ‘Zed is the fact that capturing an image from the screen is overly complicated, and the official documentation requires dedicated software and a lot of rigolmarole. Now there’s a simple python script that grabs a screen cap from a Rigol scope.

The usage of this python script is as simple as plugging the DS1054Z into your USB port and running the script. A PNG of whatever is on the screen then appears on your drive. Testing has been done on OS X, and it probably works on Linux and Windows. It’s a simple tool that does one job, glory and hallelujah, people are still designing tools this way.

This work was inspired by the efforts of [cibomahto], who spent some time controlling the Rigol with Linux and Python. This work will plot whatever is being captured by the scope in a window, in Linux, but sometimes you just need a screencap of whatever is on the scope; that’s why there were weird Polaroid adapters for HP scopes in the day.

Yes, it’s a simple tool that does one job, but if you need that tool, you really need that tool. [rdpoor] is looking for a few people to test it out, and of course pull requests are accepted.

Building An Artisanal Tape Measure

March 27, 2019 by Tom Nardi 13 Comments

Some tools are so common, so basic, that we take them for granted. A perfect example is the lowly tape measure. We’ve probably all got a few of these kicking around the lab, and they aren’t exactly the kind of thing you give a lot of thought to when you’re using them. But while most of us might not give our tape measure a second thought, [Ariel Yahni] decided to create an absolutely gorgeous new enclosure for his. Because if you’re going to measure something, why not look good doing it?

A CNC router is used to carve the body of the new tape measure out of a solid block of wood and cut a top plate out of clear acrylic. [Ariel] then used an angle grinder to cut off a small section of steel rod which he secured into a carved pocket in the base using epoxy. Finally, the internals of a commercial tape measure were inserted into this new enclosure, and the acrylic top was screwed down into place.

[Ariel] has made the DXF files for this project public for anyone else who wants to carve out their own heirloom tape measure, though it seems likely the designs will need some tweaking depending on the make and model of donor tape measure. While this might not be the most technically impressive project to run on Hackaday, it’s still a fantastic example of the sort of bespoke designs that are made possible with modern manufacturing methods.

This design reminds us of a similar project to turn a basic Honda key fob into a true conversation piece with the addition of some CNC’d hardwood and aluminum.

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Save An Old Drill From Landfill, With Some Lithium-Ion Magic

March 27, 2019 by Jenny List 39 Comments

What do you do, when your trusty cordless drill starts to lose battery capacity? You bought it a decade ago and parts are a distant memory, so there’s no chance of buying a new pack. If you are [Danilo Larizza], you strip away the old NiMh cells, and replace them with a custom pack (Italian, Google Translate link) made from 18650 Li-ion cells.

The build is a straightforward one to anyone familiar with lithium-ion packs, but to a battery newbie it should serve as a handy step-by-step description. He starts by selecting a range of matched cells from discarded laptop batteries and adds an off-the-shelf battery management board to keep everything safe. Interestingly he appears to have soldered his wires to the cells rather than the more usual spot-welding, sadly for many of us a spot-welder is beyond our means. It would be interesting to know both the mechanical integrity of the resulting connection and whether the heat of soldering might in some way affect the cells.

Firing up the drill with the new pack is not the immediate success he hoped it would be, the start-up current is so high that the battery management board goes into a fault condition. This situation is resolved with a model that can take more current, and he can take his drill out once more.

If you are annoyed by the rise of cordless tools, you’re in good company. Meanwhile if you lack a spot-welder for batteries, have a look at one of the nicer ones we’ve seen.

Testing A Battery-Powered Mini Spot Welder

March 25, 2019 by Donald Papp 27 Comments

Did you ever see a thin metal tab bonded to a battery terminal with little pock marks? That’s the work of a spot welder. Spot welding is one of those processes that doesn’t offer much in the way of alternatives; either one uses a spot welder to do the job right, or one simply does without. That need is what led [Erwin Ried] to purchase a small, battery-powered spot welder from a maker in Korea and test it out on nickel strips.

The spot welder [Erwin] used is the work of a user by the name of [aulakiria] (link is Korean, machine translation here) and is designed to be portable and powered by batteries commonly used for RC. [Erwin] is delighted with the results, and demonstrates the device in the video embedded below.

Spot welder projects see a lot of DIY, some of which are successful while others are less so. Our own [Sean Boyce] even gave making a solar-powered spot welder a shot, the results of which he described as “nearly practical!”

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Create Green, Soldermasked PCBs With Fritzing

March 22, 2019 by Brian Benchoff 12 Comments

Even though you can easily order a PCB from any one of a dozen board houses and have it on your desk in a few weeks, there’s still a need for home-made circuit boards. If it’s because you have very special or strange requirements, you want to save money, or you need to suffer for your art, you can make printed circuit boards at home. You can even apply soldermask. It’s easy, and [Renzo] is here to show you how.

The beginnings of this tutorial cover well-tread territory such as building a CNC router, laying out a circuit, and cutting a piece of single-sided, copper clad board. If you stopped right there, after milling traces into a board, you would have a functioning circuit. But it wouldn’t look good; a piece of copper does not a PCB make, and you need soldermask. That’s where the real work comes in.

Applying the soldermask meant there needed to be places without soldermask, mostly the vias and through-holes. For this, [Renzo] pulled the copper pad layer out of Fritzing, printed it on a transparency sheet, and finally applied the UV-curing soldermask. This came as a kit, and right now, you can get 10 ml of green, red, blue, yellow, and black UV-curing soldermask, and a UV flashlight for ten dollars on the usual Internet shops. This soldermask was lathered on, rolled out, and exposed with the UV flashlight. After a quick wash in acetone, the result is a perfect PCB.