Frequency Counting A Different Way

September 12, 2019 by Al Williams 9 Comments

Counting frequency is one of those tasks that seems simple on the face of it, but actually has quite a bit of nuance. There are two obvious methods, of which the first is to count zero crossings for some period. If that period is one second you are done, otherwise it’s a simple enough case of doing the math. That is, if you count for half a second, multiply the result by 2, or if you count for 10 seconds, divide by 10. The other obvious method is to measure the period of a single cycle as accurately as you can. Then there’s this third method.from [WilkoL], which simultaneously counts a known reference clock alongside the frequency to be measured. You can see the result in the video, below.

The first method is easy but the lower the frequency you want to measure, the longer you have to count to get any real resolution. Also, you need the time base to be exact. For the second method, you need to be able to make a highly precise measurement. The reason [WikolL] chose the third method is that it doesn’t require a very precise time base — a moderately accurate reference oscillator will do. The instrument gets good resolution quickly at both high and low frequencies. Continue reading “Frequency Counting A Different Way” →

Modified Tombstone Welder Contains A Host Of Hacks

September 12, 2019 by Dan Maloney 30 Comments

State-of-the-art welding machines aren’t cheap, and for good reason: pushing around that much current in a controlled way and doing it over an entire workday takes some heavy-duty parts. There are bargains to be found, though, especially in the most basic of machines: AC stick welders. The familiar and aptly named “tombstone” welders can do the business, and they’re a great tool to learn how to lay a bead.

Tombstones are not without their drawbacks, though, and while others might buy a different welder when bumping up against those limits, [Greg Hildstrom] decided to hack his AC stick welder into an AC/DC welder with TIG. He details the panoply of mods he made to the welder, from a new 50 A cordset made from three extension cords where all three 12 gauge wires in each cord are connected together to make much larger effective conductors, to adding rectifiers and a choke made from the frame of a microwave oven transformer to produce DC output at the full 225 A rating. By the end of the project the tombstone was chock full of hacks, including a homemade foot pedal for voltage control, new industry-standard connectors for everything, and with the help of a vintage Lincoln “Hi-Freq” controller, support for TIG, or tungsten inert gas welding. His blog post shows some of the many test beads he’s put down with the machine, and the video playlist linked below shows highlights of the build.

This isn’t [Greg]’s first foray into the world of hot metal. A few years back we covered his electric arc furnace build, powered by another, more capable welder.

Continue reading “Modified Tombstone Welder Contains A Host Of Hacks” →

Using Machinery To Make Factory-Fresh Industrial Music

September 11, 2019 by Kristina Panos 5 Comments

Many machines make music as a side effect, as anyone who owns a 3D printer can confirm. [工場音楽レーベルINDUSTRIAL JP] is working on a project to meld music and machinery in new ways. They are building a record label and a playlist based on the sights and sounds of small factories in Japan. Their videos combine the hypnotizing, rhythmic beauty of precision manufacturing process with music from local artists, and the result is like r/SoundsLikeMusic met up with How It’s Made and created a series of un-narrated industrial fever dreams.

While the focus is on high-tech factories, the content of these moodily-lit videos is pretty diverse. Never before have we been so mesmerized by the folds of an air filter or the pressing of vinyl records. Our favorite might be GOKO BANE, which takes a bumpin’ look around the Goko Spring factory. It makes us want to throw on some rags and dance like they do down in Zion.

Once in a while they will play around with the video speed of the factory process for effect, and it works nicely. If there’s any downside, it’s that no one process is shown from start to finish. But that’s not the point, anyway.

Don’t have access to a factory? Us either. But if you can get stepper motors, it’s pretty easy to make music by driving them forward, or even backward.

Thanks for the tip, [KILLERGEEK].

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.

Digital Oscilloscope Does Its Best Analog Impression

September 10, 2019 by Tom Nardi 48 Comments

Do you ever find yourself yearning for the days before digital storage oscilloscopes (DSOs)? Where even the basic scopes commanded four figures, and came in a bench-dominating form factor? No, of course you don’t. The DSO is a wonder of modern technology: for a couple hundred bucks you can have capabilities that previously would have been outside the reach of hobbyists, all in a package that’s small enough to fit on even the most cramped workbenches.

Which is why the good folks of the EEVblog forums are so confused about the OWON AS101, a modern digital oscilloscope that’s designed to look and operate like the analog CRT monsters of old. Despite the 3.7 inch LCD, users are treated to the classic analog scope look, and the switches and knobs on the front should trigger a wave of nostalgia for hackers of a certain age.

But this isn’t just some “retro” look-alike, OWON is committed to delivering on that analog experience by taking away all those modern digital features we’ve become so dependant on. This single-channel scope can’t save data to USB, doesn’t have any sort of protocol decoding capabilities, and forget about automatic…well, anything. It’s even limited to 20 MHz, just like the old-school CRT scopes that you pick up for a song at any swap meet. All for the low, low, price of $150 USD from the usual importers.

In the EEVblog thread, the best idea anyone can come up with is that the OWON AS101 is designed for educational markets in developing countries, where outdated equipment is so common that there may actually be a need for faux-analog oscilloscopes to match what’s already in use. These new-manufactured “analog” trainers can be used to get students ready for a professional life of using antiquated technology. It’s hard to believe, but sometimes we can forget how fortunate many of us are to have easy access to cheap tools and equipment.

Even still, when you can get a pocket-sized 10 MHz DSO for around $50, it’s difficult to imagine how this analog-digital hybrid could possibly attract any takers at 3x times the price. If any of our readers would care to shed some light on this unusual piece of gear, we’d love to hear it.

Continue reading “Digital Oscilloscope Does Its Best Analog Impression” →

Cheap Stereo Microscope Helps With SMD

September 8, 2019 by Al Williams 22 Comments

Soldering is best done under magnification. Parts become ever smaller and eyes get weaker, so even if you don’t need magnification now, you will. [Makzumi] didn’t want to shell out $400 or more for a good microscope so he hacked one from some cheap binoculars from the toy section on Amazon.

A lot of magnifiers aren’t really good for soldering because the distance between the work and the lens isn’t very large. The hacked ‘scope has about 4 inches of working distance, which is plenty of room to stick some solder and a hot iron under there. The resulting magnification is about 12 or 15X and he claims that the cell phone pictures he’s included aren’t as good as really looking through the eyepieces yourself.

Continue reading “Cheap Stereo Microscope Helps With SMD” →

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.