Open Source Multimeter Raises The Bar For DIY Tools

December 25, 2024 by Tom Nardi 39 Comments

Whether you only dabble in electronics as a hobby or it’s your full-time job, there are few tools as indispensable as the multimeter. In fact, we’d be willing to bet nearly everyone reading this site owns at least one of them. But as common and mindbogglingly useful as they may be, they aren’t perfect. Even the high-end models will invariably have some annoyance that only reveals itself once you become intimately acquainted with it.

Most people would just live with those quirks, especially when dealing with a cheaper model. But not [John Duffy]. Deciding nothing but perfection would do, he took every favorite feature he’d ever run into while using other multimeters and combined them into his scratch-built HydraMeter. In the process, he managed to come up with a few new ideas that push this device into a league of its own.

Some of the features of the HydraMeter will look familiar. You might even have them on your own personal meter, such as the wireless removable display module. Other features you’ll wish your meter had, such as the removable cartridge on the front of the device that lets you rapidly swap out a burned fuse. On the other side of the spectrum, there are some esoteric features that might leave you scratching your head. The ability to tell exactly how the meter is configured at a glance thanks to its exclusive use of toggle switches has a certain hacker appeal, but it’s a tricky user interface for most folks.

While the overall design of the HydraMeter may be divisive, one thing we can all agree on is that getting the project to this state took incredible determination. Over the years we’ve only seen a handful of individuals attempt to develop their own multimeters, and even then, none of them approached this level of fit and finish. The fact that [John] has turned all that effort over to the community by releasing his design under the CERN license is truly admirable.

[John] brought the HydraMeter out to Pasadena back in November for Supercon, and it got quite a reaction. And if you don’t like the user interface, it’s not hard to imagine how you could change it. This project has unquestionably pushed the state of the art for open source multimeters forward, and we’re eager to see where it goes from here.

Continue reading “Open Source Multimeter Raises The Bar For DIY Tools” →

Break Me Off A Piece Of That Open Source Serial Adapter

December 25, 2024 by Tom Nardi 12 Comments

We know, you’ve already got a USB to serial adapter. Probably several of them, in fact. But that doesn’t mean you couldn’t use one more — especially when it’s as as cleverly designed as this one from [Anders Nielsen].

The first thing you notice about this adapter, and the big departure from the ones that are likely littering your parts bin, is that it terminates in a full-size male DSUB9 connector. With the ability to be directly plugged into a RS-232 port, this adapter will certainly catch the eye of retrocomputer enthusiasts. With a clever arrangement of jumpers, you can even reconfigure the RX and TX lines to be straight-through or cross over as needed.

But if you’re working with something that doesn’t have a literal serial port, no worries. All of the lines coming from the CH340G chip are broken out to a header so you can connect it up to whatever device you’re working with via jumpers.

In fact, if you’re really sure you’ll never need that RS232 feature, the PCB is even designed in such a way that you can simply snap it off. Admittedly it might seem a little odd to get a device like this if you didn’t want that capability. But once broken off, it’s not like the components go to waste. [Anders] has designed the board in such a way that if you flip it over and install a right-angle header, you can use the RS232 segment on a breadboard.

But the list of features doesn’t stop there. There’s also a 3.3 V regulator on board that you can use to power external circuits, as well as breakouts for the data lines in the USB-C connector. In keeping with the theme of the device, that part of the PCB can also be snapped off if you want to use it elsewhere.

Most folks probably’ won’t need all the capabilities offered by this particular serial adapter, and that’s fine. We’re still happy that it’s out in the wild and available for the community to use and adapt as an open source project.

Continue reading “Break Me Off A Piece Of That Open Source Serial Adapter” →

Building A Custom Swiss Army Knife

December 21, 2024 by Lewin Day 15 Comments

The Swiss Army knife is the most well-known multitool, combining a bunch of functionality into a compact package. [Jeff Gough] decided to build a custom example featuring a selection of his favorite tools.

He documents the build in a video series on YouTube (see below). [Jeff] decided to take on the project as a gift for his mother after she’d mentioned she’d wanted a Swiss Army-style knife with a horse’s hoof tool and finished in the classic shade of British Racing Green.

[Jeff] starts by disassembling an existing knife, taking care not to damage it in the process. He then makes and installs multiple custom tools, including the aforementioned horse hoof tool and a RADAR/NKS key for opening disabled toilets in the UK. He even crafts a bespoke Philips head screwdriver, too. Finally, he assembles everything back together and gives the build a beautiful green finish.

A Swiss Army knife can be a neat gift, but it’s even nicer when it’s got a personal touch like this one. We’ve featured some other nifty multitools before, too. Not all Swiss Army knives actually contain a, you know, knife. No kidding.

Continue reading “Building A Custom Swiss Army Knife” →

Embossing Leather With A Pipe Bender And 3D Printed Tooling

December 20, 2024 by Lewin Day 12 Comments

Embossed leather belts can be deliciously stylish. However, the tooling for making these fashionable items is not always easy to come by, and it rarely comes cheap. What do we do when a tool is expensive and obscure? We 3D print our own, as [Myth Impressions] demonstrates.

The build is based around a Harbor Freight pipe bender. However, instead of the usual metal tooling, it’s been refitted with a printed embossing ring specifically designed for imprinting leather. The tool features raised ridges in an attractive pattern, and the pipe bender merely serves as a straightforward device for rolling the plastic tooling over a leather belt blank. Once cranked through the machine, the leather belt comes out embossed with a beautiful design.

It’s a neat project, and the 3D printed tooling works surprisingly well. The key is that leather is relatively soft, so it’s possible to use plastic tools quite effectively. With that said, you can even form steel with printed tooling if you use the right techniques.

We’ve seen some other neat leatherworking hacks before, like this nicely-modified Singer sewing machine.

Continue reading “Embossing Leather With A Pipe Bender And 3D Printed Tooling” →

Multimeter Gets Socket Upgrade To Use Nicer Probes

December 20, 2024 by Lewin Day 11 Comments

[Piffpaffpoltrie] had a problem. They found the InLine VA40R to be a perfectly usable multimeter, except for a couple of flaws. Most glaring among these were the tiny sockets for the test probes. These proved incompatible with the probes they preferred to use, so naturally, something had to be done.

The desire was to see the multimeter work with [Piffpaffpoltrie]’s connector of choice: the 4 mm Multi Contact banana plug from Stäubli. Swiss-made, gold-plated, and highly reliable, nothing else would do. The original sockets on the multimeter were simply too small to properly accept these, so to make them work, they were machined down, drilled, tapped, and then fitted with a short M3 screw which was then soldered in place. This short length of thread then allowed the new sockets to bolt right into the PCB in place of the original sockets.

Ultimately, many would just buy a new multimeter. This hack is a fiddly and time-consuming one, but it’s kind of neat to see someone go to such lengths to customize their tools to their own satisfaction.

We don’t see a lot of multimeter hacks, because these tools usually get all the necessary features from the manufacturer. Still, the handful we’ve featured have proven most interesting. If you’re tinkering away at customizing your own test gear, don’t hesitate to drop us a line!

A Compass That Looks To The Stars

December 17, 2024 by Bryan Cockfield 19 Comments

Although a lot of tools have been digitized and consolidated into our smartphones, from cameras, music players, calendars, alarm clocks, flashlights, and of course phones, perhaps none are as useful as the GPS and navigational capabilities. The major weakness here, though, is that this is a single point of failure. If there’s no cell service, if the battery dies, or you find yourself flying a bomber during World War II then you’re going to need another way to navigate, possibly using something like this Astro Compass.

The compass, as its name implies, also doesn’t rely on using the Earth’s magnetic field since that would have been difficult or impossible inside of an airplane. Instead, it can use various celestial bodies to get a heading. But it’s not quite as simple as pointing it at a star and heading off into the wild blue yonder. First you’ll need to know the current time and date and look those up in a companion chart. The chart lists the global hour angle and the declination for a number of celestial bodies which can be put into the compass. From there the latitude is set and the local hour angle is calculated and set, and then the compass is rotated until the object is sighted. After all of that effort, a compass heading will be shown.

For all its complexity, a tool like this can be indispensable in situations where modern technology fails. While it does rely on precise tabulated astrometric data to be on hand, as long as that’s available it’s almost failsafe, especially compared to a modern smartphone. Of course, you’ll also need a fairly accurate way of timekeeping which can be difficult in some situations.

Continue reading “A Compass That Looks To The Stars” →

Tech In Plain Sight: Table Saw Safety

December 17, 2024 by Al Williams 76 Comments

If you ask around a wood shop, most people will agree that the table saw is the most dangerous tool around. There’s ample evidence that this is true. In 2015, over 30,000 ER visits happened because of table saws. However, it isn’t clear how many of those are from blade contact and how many are from other problems like kickback.

We’ve seen a hand contact a blade in a high school shop class, and the results are not pretty. We’ve heard of some people getting off lucky with stitches, reconstructive surgery, and lifelong pain. They are the lucky ones. Many people lose fingers, hands, or have permanent disfiguration and loss of function. Surgeons say that the speed and vigor of the blade means that some of the tissue around the cut vanishes, making reconstruction very difficult.

Modern Tech

These days, there are systems that can help prevent or mitigate these kinds of accidents. The most common in the United States is the patented SawStop system, which is proprietary — that is, to get it, you have to buy a saw from SawStop.

Continue reading “Tech In Plain Sight: Table Saw Safety” →