Scopetrex Is A Game Console… For Your Oscilloscope!

May 7, 2020 by Jenny List 35 Comments

You’ve always wanted a game console at your bench, but maybe you haven’t had space for a monitor or TV set? Wouldn’t it be useful if the screen you do have on your bench could also play games? [Tube Time] has fixed this problem, with Scopetrex, a vector graphic console for your oscilloscope. In fact, it’s better than just a console, because it’s a clone of the legendary Vectrex, the vector-based console with built-in CRT screen from the 1980s.

The board itself is a slightly enhanced version of the original, offering not extra functionality but the ability to substitute some of the parts for more easily found equivalents. It gives full control over display size and brightness, can use the cheaper 6809E processor and AY-3-9810 sound chip if necessary, and only needs a single 5 volt supply. There’s also a custom controller board, which is handly Vectrex-compatible. All you will need to play Vectrex games on your ‘scope once you’ve built this board, are a copy of the Vectrex ROM, and some games.

The Vectrex holds an enduring fascination for our community, and has appeared here many times. Particularly memorable is a CRT replacement, and then of course there’s the never-released mini Vectrex prototype.

Thanks [Justin List] for the tip.

Scratch Built Magnetic Vise Stays Where You Need It

May 1, 2020 by Tom Nardi 19 Comments

For those who might not have run into one before, a magnetic vise is used when you want to quickly anchor something to a metal surface at an arbitrary position. They’re often used to hold the workpiece down when machining, and can be a real time saver if a lot of repositioning is involved.

[Workshop From Scratch] recently wanted to put together one of these handy pieces of gear, and as we’ve come to expect from his channel, the finished product is an absolute beast. Starting with little more than scraps of metal, the video after the break takes the viewer on a fascinating journey that ends with some demonstrations of the vise in action.

Conceptually, this build is relatively simple. Start with a vise, put a hollow base on it, and fit it with powerful electromagnets that will anchor it down once you flip the switch. Technically you could just build a magnetic base and bolt a commercially available vise onto it, but that’s not how [Workshop From Scratch] does things.

Every element of the build is done by hand, from the pattern cut into the jaws to the t-handle nut driver that gets adapted into a very slick crank. Of particular interest is how much effort is put into grinding down the surface of the electromagnets so they are perfectly flush with the base of the vise. Incidentally, these beefy electromagnets were salvaged from automotive air conditioning compressors, so you might want to add that to your junkyard shopping list.

Eagle-eyed readers might recognize the surface [Workshop From Scratch] uses the vise on as the custom drill press table he built a few months ago. These videos are not only reminders of what you can accomplish when you’ve mastered the use of a few common tools, but just how much design and thought goes into the hardware many of us take for granted.

Continue reading “Scratch Built Magnetic Vise Stays Where You Need It” →

A Custom Saw Designed For Close Quarters Making

April 29, 2020 by Tom Nardi 3 Comments

It probably goes without saying that we’d all love to have a huge, well-appointed, workshop. But in reality, most of us have to make do with considerably less. When trying to fit tools and equipment into a small space you need to get creative, and if you can figure out a way to squeeze multiple functions out of something, all the better.

Wanting to get as much use out of his space as possible, [Chris Chimienti] decided that his best bet would be to design and build his own folding combination table. Using interchangeable inserts it can switch between being a table saw and a router, and with its extendable arms, also serves as a stand for his miter saw. Of course when not cutting, it makes a handy general purpose work surface.

In the videos after the break, [Chris] takes viewers through the design and construction of what he calls the “Sinister Saw”, which is made somewhat more complicated by the fact that he obviously doesn’t have a table saw to begin with. Cutting out the pieces for the table itself and the panels that would eventually become home to the router and circular saw took some careful work with clamps and saw horses to make sure they were all perfectly square.

But the wooden components of the Sinister Saw are only half of the story. The table is able to extend by way of an aluminum extrusion frame, and there are numerous 3D printed parts involved for which [Chris] has provided the STL files. We particularly like the box that holds the emergency stop button and relocates the tool’s battery to the front panel, which looks to be an evolution of his previous work in 3D printing cordless tool adapters. We could certainly see this part being useful on other projects that utilize these style of batteries.

In the other extreme, where you want to build your own tools and have plenty of space, you could try making everything out of giant slabs of stone.

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Grace Under Pressure: Shelley Green Celebrates Crimped Connections

April 27, 2020 by Kristina Panos 18 Comments

We think it’s pretty safe to assume that most of the electrical connections our readers are making out there involve solder or solder paste. But we’ve all made a crimp connection or two in our lifetimes. Maybe you’ve squeezed a butt connector here and there, or made an Ethernet cable. Beyond getting the wiring order right in the Ethernet cable, how much did you wonder about what was happening inside the connector?

It may seem like solder is the superior option for making a low-resistance electrical connection. After all, you’re welding metals together with another metal. And this is usually all fine and good for circuit boards with sedentary indoor lives. But if a joint needs to be mechanically stable and survive in potentially harsh environments, you don’t want an alloy holding things together. You want metal to metal contact, and crimping is where it’s at.

A well-made crimp should last for several decades, but as Shelley Green explained in her talk at the 2019 Hackaday Superconference, good quality crimps don’t happen by accident. Good crimps are meticulously designed, and carefully executed from start to finish.

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Defocused Laser Welding Fabric Proves There’s Many Ways To Slice It

April 27, 2020 by Sonya Vasquez 15 Comments

Laser cutters are certainly a Hackerspace staple for cutting fabrics in some circles. But for the few fabrics derived from non-woven plastics, why not try fusing them together? That’s exactly what [Dries] did, and with some calibration, the result is a speedy means of seaming together two fabrics–no needles necessary!

The materials used here are non-woven goods often used in disposable PPE like face masks, disposable aprons, and shoe coverings. The common tool used to fuse non-woven fabrics at the seams is an ultrasonic welder. This is not as common in the hackerspace tool room, but laser cutters may be a suitable stand-in.

Getting the machine into a production mode of simply cranking out clothes took some work. Through numerous sample runs, [Dries] found that defocusing the laser to a spot size of 1.5mm at low power settings makes for a perfect threadless seam. The resulting test pockets are quite capable of taking a bit of hand abuse before tearing. Best of all, the fused fabrics can simply be cut out with another pass of the laser cutter. For fixtures, [Dries] started with small tests by stretching the two fabrics tightly over each other but suggests fixtures that can be pressed for larger patterns.

It’s great to see laser-cutters doubled-up as both the “glue” and “scissors” in a textile project. Once we get a handle on lasering our own set of scrubs, why not add some inflatables into the mix?

KiCad Panelization Made Easy

April 25, 2020 by Mike Szczys 14 Comments

There’s a new Python-based script that will panelize your KiCad circuit boards from the command line. The project by [Jan Mrázek] is called KiKit and works on .kicad_pcb files to arrange them in a grid with your choice of mousebites or v-cuts for separating the boards after production.

When working with smaller boards it’s common practice to group them together into panels. This is done to speed up PCB assembly as multiple boards can have solder paste applied, go through a pick and place machine, and be sent into the reflow oven as a single unit. Often this is done manually, but in many cases this script will save you the time while delivering the results you need.

Let’s say you really wanted to make a whole bunch of those Xling open source Tamagotchi-like key fobs we saw a couple of weeks back. Using KiKit you can gang up six of the boards at a time, using “mousebites” to keep them together during production but make it easy to separate them after all the components are soldered:

/usr/local/bin/kikit panelize grid --space 3 --gridsize 2 3 --tabwidth 3 --tabheight 3 --htabs 2 --vtabs 1 --mousebites 0.5 1 0.25 --radius 1 Xling/hardware/xling.kicad_pcb xling_panel.kicad_pcb

You can see that the parameters let you set space between the boards, number of boards in the grid, width of the tabs, tab dimensions, number of tabs between boards, and even the radius of the curve where the tabs meet the board. These settings were pulled from the examples page, which demonstrates outcomes for many different settings options.

If you want to give this a try, we suggest installing directly from the repository, as improvements are ongoing and the pip3 version didn’t have all of the options shown in the examples. For us this was as easy as sudo python3 setup.py install and then calling the script with the full path /usr/local/bin/kikit.

Results from this board are both impressive and cautionary. You can see the top edge of the design is recessed yet the most up-to-date version of KiKit was still able to make the connection. However, how this affects the USB connector on the bottom of the board design may be something to consider before pulling the trigger on your panel order.

So. You Bought A VNA. Now What?

April 23, 2020 by Jenny List 33 Comments

It’s never too late in life for new experiences, but there’s a new experience I had a few weeks ago that I wasn’t expecting. I probably received my first piece of test equipment – a multimeter – in the early 1980s, and since then every time I’ve received a new one, whether an oscilloscope, logic analyser, spectrum analyser or signal generator, I’ve been able to figure out how to use it. I have a good idea what it does, and I can figure out whatever its interface may be to make it do what I want it to. My new experience came when I bought a piece of test equipment, and for the first time in my life didn’t have a clue how to use it.

That instrument is a Vector Network Analyser, or VNA, and it’s worth spending a while going through the basics in case anyone else is in the same position. My VNA is not a superlative piece of high-end instrumentation that cost the GDP of a small country, it’s the popular $50 NanoVNA that has a fairly modest frequency range and performance, but is still a functional VNA that can take useful measurements. But I’m a VNA newbie, what does a VNA do? Continue reading “So. You Bought A VNA. Now What?” →