Pico Logic Analyzer Gets New Version

[Happy Little Diodes] built a Pi Pico logic analyzer designed by [El Dr. Gusman] using the original design. But he recently had a chance to test the newest version of the design, which is a big upgrade. You can see his take on the new design in the video below.

The original design could sample 24 channels at 100 MHz and required two different PCBs. The new version uses a single board and can operate up to 400 MHz. There’s also a provision for chaining multiple boards together to get more channels. You can set the level shifters to use 5 V, 3.3 V, or an external voltage. Since [Happy] is working on a ZX Spectrum, the 5 V conversion is a necessity.

The code is on GitHub, although it warns you that version six — the one seen in the video — isn’t stable, so you might have to wait to make one on your own. The software looks impressive and there may be some effort to integrate with Sigrok.

If you missed our coverage of the earlier version, you can still catch up. Dead set on Sigrok support? [Pico-Coder] can help you out.

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3D Printed Caliper Extensions Make Hole Measurement Easier

If there’s anything more frustrating than mounting holes that don’t line up with the thing you’re mounting, we don’t know what it could be. You measure as carefully as possible, you drill the holes, and yet at least one hole ends up being just out of place. Sometimes you can fudge it, but other times you’ve got to start over again. It’s maddening.

Getting solid measurements of the distance between holes would help, which is where these neat snap-on attachments for digital calipers come in. [Chris Long] came up with the 3D printed tools to make this common shop task a little easier, and they look promising. The extensions have cone-shaped tips that align perfectly with the inside edge of the caliper jaws, which lines the jaws up with the center of each hole. You read the center-to-center distance directly off the caliper display, easy peasy.

Of course, there’s also the old machinist’s trick (last item) about zeroing out the calipers after reading the diameter of one of the holes and then measuring the outside-to-outside distance between the two holes. That works great when you’ve got plenty of clearance, but the shorter inside jaws might make measuring something like a populated PCB with this method tricky. For the price of a little filament and some print time, these might be just the tool to get you out of a bind.

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VNAs And Crystals

Oscillators may use crystals as precise tuned circuits. If you have a vector network analyzer (VNA) — or even some basic test equipment — you can use it to learn the parameters of a crystal. [All Electronics Channel] has the details, and you can see how in the video below.

There was a time when a VNA was an exotic piece of gear, but these days they are relatively common. Crystal parameters are important because crystals have a series resonance and a parallel resonance and they are not at the same frequency. You also may need to know how much loading capacitance you have to supply to get the crystal at the right frequency.

Sometimes, you want to pull the crystal frequency, and the parameters will help you figure that out, too. It can also help if you have a crystal specified as series in a parallel-mode oscillator or vice versa.

If you don’t have a VNA, you can use a tracking signal generator, as [GrĂ©gory] shows towards the middle of the video. The quality of a tuned circuit depends on the Q factor, and crystals have a very high Q factor.

We did something similar in 2018. The other way to pull a crystal frequency is a bit extreme.

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OSHW Battery Tester Aims To Help Tame Lithium Cells

It’s no exaggeration to say that the development of cheap rechargeable lithium-ion batteries has changed the world. Enabling everything from smartphones to electric cars, their ability to pack an incredible amount of energy into a lightweight package has been absolutely transformative over the last several decades. But like all technologies, there are downsides to consider — specifically, the need for careful monitoring during charging and discharging.

As hardware hackers, we naturally want to harness this technology for our own purposes. But many are uncomfortable about dealing with these high-powered batteries, especially when they’ve been salvaged or come from some otherwise questionable origin. Which is precisely what the Smart Multipurpose Battery Tester from [Open Green Energy] is hoping to address.

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Torque Testing 3D Printed Screws

Unless you’ve got a shop with a well-stocked hardware bin, it’s a trip to the hardware store when you need a special screw. But [Sanford Prime] has a different approach: he prints his hardware, at least for non-critical applications. Just how much abuse these plastic screws can withstand was an open question, though, until he did a little torque testing to find out.

To run the experiments, [Sanford]’s first stop was Harbor Freight, where he procured their cheapest digital torque adapter. The test fixture was similarly expedient — just a piece of wood with a hole drilled in it and a wrench holding a nut. The screws were FDM printed in PLA, ten in total, each identical in diameter, length, and thread pitch, but with differing wall thicknesses and gyroid infill percentages. Each was threaded into the captive nut and torqued with a 3/8″ ratchet wrench, with indicated torque at fastener failure recorded.

Perhaps unsurprisingly, overall strength was pretty low, amounting to only 11 inch-pounds (1.24 Nm) at the low end. The thicker the walls and the greater the infill percentage, the stronger the screws tended to be. The failures were almost universally in the threaded part of the fastener, with the exception being at the junction between the head and the shank of one screw. Since the screws were all printed vertically with their heads down on the print bed, all the failures were along the plane of printing. This prompted a separate test with a screw printed horizontally, which survived to a relatively whopping 145 in-lb, which is twice what the best of the other test group could manage.

[Sanford Prime] is careful to note that this is a rough experiment, and the results need to be taken with a large pinch of salt. There are plenty of sources of variability, not least of which is the fact that most of the measured torques were below the specified lower calibrated range for the torque tester used. Still, it’s a useful demonstration of the capabilities of 3D-printed threaded fasteners, and their limitations.

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Modular Breadboard Snaps You Into Benchtop Tidiness

Solderless breadboards are a fantastic tool for stirring the creative juices. In a few seconds, you can go from idea to prototype without ever touching the soldering iron. Unfortunately, the downside to this is that projects tend to expand to occupy all the available space on the breadboard, and the bench surrounding the project universally ends up cluttered with power supplies, meters, jumpers, and parts you’ve swapped in and out of the circuit.

In an attempt to tame this runaway mess, [Raph] came up with this neat modular breadboard system. It hearkens back to the all-in-one prototyping systems we greatly coveted when the whole concept of solderless breadboards was new and correspondingly unaffordable. Even today, combination breadboard and power supply systems command a pretty penny, so rolling your own might make good financial sense. [Raph] made his system modular, with 3D-printed frames that lock together using clever dovetail slots. The prototyping area snaps to an instrumentation panel, which includes two different power supplies and a digital volt-amp meter. This helps keep the bench clean since you don’t need to string leads all over the place. The separate bin for organizing jumpers and tidbits that snaps into the frame is a nice touch, too.

Want to roll your own? Not a problem, as [Raph] has thoughtfully made all the build files available. What’s more, they’re parametric so you can customize them to the breadboards you already have. The only suggestion we have would be that making this compatible with [Zack Freedman]’s Gridfinity system might be kind of cool, too.

A pair of hands hold two dark brown boards perpendicular two each other on a light brown benchtop. There are two light brown oval dowels in the end of one board that then project toward holes in the opposite board. Circular holes in the oval dowels are visible perpendicular to the second board, and will match up with holes in the board once pressed in. A cylindrical dowel is laying next to the joint and will be placed into the circular holes once assembled.

Creating A Signature Wood Joint

We really love when makers make their construction techniques evident in an aesthetically-pleasing way, and [Laura Kampf] has created a clever joint that reveals how a piece is made.

[Kampf] is a big fan of using her domino joiner, which is similar to biscuits or dowel joinery, but she didn’t love how it hid the construction of the joint. She first figured out an “off label” use of the joiner by running it from the outside of the joint to show the exposed domino from one end.

Building on the concept to show an interesting contrast on both sides of the joint, she drilled a hole perpendicular the domino and placed a dowel through it, creating a locking joint. The choice looks great once a finish is applied to really accentuate the contrast, and another bonus is that if glue is only applied to the dowel and domino, it becomes trivial to separate the joint if needed by drilling out the dowel.

If you’d like to see some other interesting ways to join wood, how about this laser-cut wedge tenon, soda bottle heat shrink, or this collection of CNC joints.

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