Reverse Engineering Teaches An Old Scope New Tricks

July 18, 2020 by Adil Malik 8 Comments

[PMercier] clearly loves his old Tektronix TDS3014 scope, which did however lack essentially modern connectivity such as an Ethernet port for control and a USB port for a convenient way to capture screenshots. So he decided to do some in-depth reverse engineering and design his own expansion card for it. The scope already has an expansion port and an expansion card, but given this model was first released in 1998, purchasing an OEM part was not going to be an option.

They don’t make ’em like they used to. Test equipment is today is built to last a decade — but usually lives on much longer. This is certainly true for the previous generations of kit. It’s no surprise that for most of us, hand-me-downs from universities, shrewd eBay purchasing, and even fruitful dumpster dives are a very viable way to attain useful and relevant test equipment. Now, while these acquisitions are more than adequate for the needs of a hobbyist lab, they are admittedly outdated and more to the point, inaccessible from a connectivity and communication standpoint. A modern lab has a very high degree of automated data acquisition and control over ethernet. Capturing screen dumps on a USB is a standard feature. These modern luxuries don’t exist on aging equipment conceived in the age of floppy disks and GPIB.

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Touch Screen Reflow Oven Pulls Out All The Stops

July 16, 2020 by Tom Nardi 17 Comments

We’ve seen plenty of simple reflow ovens, and there’s an excellent chance that some of the people reading these words have even thrown their own together. A minimal example isn’t much more than a old toaster oven, a Solid State Relay (SSR), a thermocouple, and a microcontroller to get them all talking. But if you’re like [Mangy_Dog] and willing to put in a bit more effort, the final result can be a capable piece of equipment that will be the envy of the hackerspace.

This build started as most do, with a search for a used toaster oven. But in the end he actually found a German model cheap enough that he could buy it new without going over budget for the project. Though he soon found out why: when it arrived, the so-called “pizza oven” was far smaller than he’d imagined. Luckily, it ended up being the perfect size for PCBs.

Unfortunately, the heating elements weren’t quite where he wanted them. Even after wrapping the heating chamber with ceramic insulation, a feature that was likely left off the original oven to cut costs, he says the temperature would only rise about 1 degree per second. So he added an additional halogen heating element at the top of the oven which pushed that rate up to 6 degrees per second.

Control is provided by an Arduino Pro Mini and a touch screen display with some very slick graphics. There’s the expected thermocouple to detect the current temperature, but while the earlier versions of the electronics used the aforementioned SSR to control the heating elements, [Mangy_Dog] eventually replaced it with a dimmer module rated for 4000 watts. After coming up with a circuit that allowed him to control the dimmer with the Arduino, this module gave for much finer control over the chamber temperature. Plus it apparently kept all the lights in his house from flickering when the elements kicked in at 100%, which was a nice bonus.

This isn’t the first time we’ve seen somebody shoehorn an LCD into an off-the-shelf toaster oven, but it’s certainly one of the most polished examples to ever come our way. When even commercially available units need some hacking to reach feature parity with DIY versions, building your own reflow oven still seems like the way to go in 2020.

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No Assembly Required For This Compliant Mechanism Dial Indicator

July 15, 2020 by Dan Maloney 10 Comments

If you’ve ever had the good fortune — or, after a shop mishap, the misfortune — to see the insides of a dial indicator, you’ll know the workings of these shop essentials resemble nothing so much as those of a fine Swiss watch. The pinions, gears, and springs within transmit the slightest movement of the instrument’s plunger to a series of dials, making even the tiniest of differences easy to spot.

Not every useful dial indicator needs to have those mechanical guts, nor even a dial for that matter. This compliant mechanism 3D-printed dial-free indicator is perfect for a lot of simple tasks, including the bed leveling chores that [SunShine] designed it for. Rather than print a bunch of gears and assemble them, [SunShine] chose to print the plunger, a fine set of flexible linkage arms, and a long lever arm to act as a needle. The needle is attached to a flexible fulcrum, which is part of the barrel that houses the plunger. Slight movements of the plunger within the barrel push or pull on the needle, amplifying them into an easily read deflection. When attached to the head of a 3D-printer and scanned over the bed, it’s easy to see even the slightest variation in height and make the corresponding adjustments. Check it out in the video below.

We’re big fans of compliant mechanisms, seeing them in everything from robot arms and legs to thrust vectoring for an RC plane. This might look like something from a cereal box, and it certainly doesn’t have the lasting power of a Starrett or Mitutoyo, but then again it costs essentially nothing, and we like that too.

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Printed It: Print-in-Place PCB Gripper

July 15, 2020 by Tom Nardi 10 Comments

The goal of Printed It is to showcase creations that truly embrace the possibilities offered by desktop 3D printing. The most obvious examples are designs that can be printed quickly and cheaply enough that they’re a valid alternative to commercially available products. But as previous entries into the series have shown, there are also technical considerations. Is it simply a duplicate of something that could be produced via traditional means, or does the design really benefit from the unique nature of 3D printing?

A perfect example is the Print-in-Place PCB Holder/Gripper created by SunShine. This design is able to hold onto PCBs (or really, whatever you wish) without any additional components. Just pull it off the bed, and put it to work. While having to add a rubber band or generic spring would hardly be an inconvenience, there’s always something to be said for a design that’s truly 100% printable.

The secret is the dual flat spiral springs integrated into the device’s jaws. While most of the common thermoplastics used in desktop 3D printing are relatively stiff, the springs have been designed in such a way that they can be printed in standard PLA. The backside of the jaws have teeth that mesh together, so the energy of the springs is combined to provide a clamping force. Serrations have been added to the jaws to catch the edge of the PCB and help stabilize it.

Visually, it’s certainly striking. The design largely eschews right angles, giving it an almost biological appearance. Many have compared it to the head of a mantis, or perhaps some piece of alien technology.

There’s no question that the design leverages the strengths of 3D printing either; there’s no other way to produce its intricate interlocking components, especially without the use of any sort of fasteners. In short, this design is an ideal candidate for Printed It. But there’s still one question to answer: does it actually work?

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Build An Everlasting Continuity Tester

July 13, 2020 by Kristina Panos 34 Comments

When you need a continuity tester at the bench, what do you reach for? Probably your multimeter, right? It may surprise you to know that the continuity tester in the meter isn’t all that sensitive, even if it’s the yellow expensive kind. [Leo]’s will beep even if there is 50Ω of resistance in the line.

Disgusted by modern commercial testers, [Leo] set out to make the ideal continuity tester in the spirit of old school tools that do one thing and do it really well. It had to be simple to use, always ready to go, and capable of measuring continuity at 5Ω or less resistance (video, embedded below).

There’s no power switch or even labels, because it doesn’t need any. Just put the probes where you want ’em, and it either beeps and lights the LED or it doesn’t. It looks simple, but inside that blast-resistant enclosure are lots of cool features that certainly make it seem like the ideal tester to us.

Our favorite has to be the transient blocking unit that works like a little circuit breaker. They’re used to protect circuits from lighting and electrostatic discharge by way of depletion-mode MOSFETs and switches to protected mode in under a microsecond. Watch [Leo] build this workbench necessity and then abuse test it with mains power after the break.

Making your own tools, however simple or complex is a great experience. If you want to up your speedy prototyping game, [Leo]’s got you covered there with a special scratching tool for hand-scribing copper PCBs. Continue reading “Build An Everlasting Continuity Tester” →

Printed TS100 Case Beats The Heat With A Bearing

July 12, 2020 by Tom Nardi 55 Comments

As we’ve said many times in the past, the creation of custom cases and enclosures is one of the best and most obvious applications for desktop 3D printing. When armed with even an entry-level printer, your projects will never again have to suffer through the indignity of getting hot glued into a nondescript plastic box. But if you’re printing with basic PLA, you need to be careful that nothing gets too hot inside.

Which was a problem when [Oleg Vint] started work on this 3D printed case for the popular TS100 soldering iron. But with the addition of a standard 608 bearing, the case provides a safe spot for the iron to cool off before it gets buttoned back up for storage. Of course, you can also use the flip-out perch to hold the iron while you’re working.

The bearing stand that served as inspiration for the case.

As [Oleg] explains on the Thingiverse page for the case, he actually blended a few existing projects together to arrive at the final design. Specifically, the idea of using the 608 bearing came from a printable TS100 stand originally designed in 2017 by [MightyNozzle]. Released under Creative Commons, [Oleg] was able to mash the bearing stand together with elements from several other printable TS100 cases to come up with his unique combined solution.

In a physical sense, this project is a great example of the sort of bespoke creations that are made possible by desktop 3D printing. But it’s also a testament to the incredible community that’s sprung up around this technology. While the logistics of it still could use some work, seeing hackers and makers swap and combine their designs like this is extremely inspiring.

[Thanks Arturo182]

Tablet Oscilloscope Claims 100 MHz, But Is It?

July 9, 2020 by Al Williams 35 Comments

[LearnElectronics] grabbed a FNIRSI tablet oscilloscope from a vendor from China. The device has a seven-inch touchscreen and claims to be a two-channel 100 MHz scope. But is it? Watch the video below and you’ll see.

Spoiler alert: [LearnElectronics] was skeptical of the 100 MHz claim and it looks like it is more like a 30 MHz analog bandwidth. Despite that, it does seem like a pretty capable 30 MHz scope in a very handy form factor and a very cheap price: as little as $120 or so, depending on where you shop.

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