Camera Sees Electromagnetic Interference Using An SDR And Machine Vision

It’s one thing to know that your device is leaking electromagnetic interference (EMI), but if you really want to solve the problem, it might be helpful to know where the emissions are coming from. This heat-mapping EMI probe will answer that question, with style. It uses a webcam to record an EMI probe and the overlay a heat map of the interference on the image itself.

Regular readers will note that the hardware end of [Charles Grassin]’s EMI mapper bears a strong resemblance to the EMC probe made from semi-rigid coax we featured recently. Built as a cheap DIY substitute for an expensive off-the-shelf probe set for electromagnetic testing, the probe was super simple: just a semi-rigid coax jumper with one SMA plug lopped off and the raw end looped back and soldered. Connected to an SDR dongle, the probe proved useful for tracking down noisy circuits.

[Charles]’ project takes that a step further by adding a camera that looks down upon the device under test. OpenCV is used to track the probe, which is moved over the DUT manually with the help of an augmented reality display that helps track coverage, with a Python script recording its position and the RF power measurements. The video below shows the capture process and what the data looks like when reassembled as an overlay on top of the device.

Even if EMC testing isn’t your thing, this one seems like a lot of fun for the curious. [Charles] has kindly made the sources available on GitHub, so this is a great project to just knock out quickly and start mapping.

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A Stylish Low Part Count Non-Contact Thermometer

A non-contact thermometer is a pretty common tool these days, and one that most of us probably have kicking around the lab. You can grab them online for as little as $10 USD, and while they’re nowhere near as capable as a thermal camera, they certainly have their uses. But even with their increased availability, there are at least two safe assumptions we can make about owners of said gadgets: they didn’t make it themselves, and they are probably pretty ambivalent about its aesthetics.

Which makes this project by [Ijon Tichy] particularly interesting. Not only is this a non-contact infrared thermometer that’s extremely easy to build should you be so inclined, but it’s actually quite attractive. In fact, if it wasn’t for the video of it in operation after the break, we would have assumed it was some kind of faux-retro cosplay prop. Even if you don’t have any use for an IR thermometer, you might just want to add one of these to your toolbox on principle.

The main components of the thermometer are a MLX90614 sensor, a gorgeous HP QDSP-6040 bubble display, and a ATtiny2313 microcontroller to tie it all together. The rest are passive components, with the exception of the TP4056 charging module that got tacked on to handle the 200 mAh lithium-ion battery. All of the components are arranged neatly in a line down the length of the thermometer, which is assembled on a piece of perfboard. Rather than go with a 3D printed enclosure that would cover it all up, [Ijon] decided to encapsulate everything in a clear epoxy resin. It looks fantastic, though you’re going to want to triple check all those solder joints before pouring on your “enclosure”.

[Ijon] has provided the diagrams and source code you need to build your own version of this artisanal thermometer, but we think with a custom PCB and perhaps a less liquid enclosure that still shows off the goods, this could be a very popular gadget for the discerning hacker. As we’ve seen, even the most basic of tools can benefit from a stylish makeover.

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KiCad Community Shines At First Ever KiCon

Last weekend was KiCon, a gathering of hardware developers from all over the world who use KiCad open source EDA software. This included many of the software engineers who drive development, people who use KiCad in their business, and those who simply love it for being a professional quality tool available for anyone to use.

From hardware show-and-tell, to the lineup of talks, and the social events each evening, there was so much packed into two (plus) days. Join me after the break for a whirlwind tour of the people and the hardware found at 2019 KiCon.

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OpenGL Shaders And An LED Cube

Back in February at the Hacker Hotel camp in the Netherlands, among the many pieces of work around the venue was a rather attractive LED cube. Very pretty, but LED cubes have been done many times before.

If a casual attendee had taken the time to ask though, they might have found something a little more interesting, for while the cube in question might have had the same hardware as the others it certainy didn’t have the same software. [Polyfloyd] had equipped his LED cube with OpenGL shaders to map arbitrary images to the cube’s pixels in 3D space.

Hardware-wise it’s the same collection of AliExpress LED panels and Raspberry Pi driver board that the other cubes use, in this case mounted on a custom laser-cut frame. Driver software comes from an open-source library round which he’s put a wrapper allowing input through a UNIX pipe. This can take the RGB output of an OpenGL shader, of which he has created both 2D to 3D and spherical projection versions. The must-see demo is a global map of light pollution, and the result is a rather impressive piece of work.

If LED cubes are your thing, don’t forget this recent Hackaday Prize entry.

Teardown: Refuel Propane Tank Monitor

Regular Hackaday readers will know that the clearance section of your local big box retailer is a great place to pick up oddball gadgets and gizmos for dirt cheap. In an era where manufacturers are rushing to make their products “smart” whether they need to be or not, the occasional ideas which fail to gain traction are just the cost of doing business. If you keep an eye out, you’re almost guaranteed to see one of these Internet of Things rejects collecting dust on a back aisle, often selling for pennies on the dollar.

Case in point, the “Refuel” propane tank monitor from Wink. Though there’s also logos for Quirky and GE on the package as well, and even a picture of the guy who came up with the idea. Essentially what we have here is a digital scale that reports the current weight of your grill’s propane tank to your phone via the Internet. A trick we might consider a fairly simple hack with a load cell and an ESP8266 under normal circumstances, but as this is a commercial product with an MSRP of $49.99 USD, its naturally been over-complicated to the point of absurdity.

Of course, one could simply lift the propane tank and get a decent estimate of its contents; a trick mastered by weekend grill masters since time immemorial. But then you wouldn’t have to make an account with Wink, or go through the very strange process of attempting to configure the device by using the flashing light of your smartphone’s screen (seriously). All so you can check how much propane is left in your grill while you’re away from home. You know, as one does.

Frankly, it’s hard for me to imagine who would actually have purchased such a thing at full retail. But of course, that’s likely why I was able to pick it up for the princely sum of $5. At that price, we can’t afford not to take a peek into this gizmo from Wink, Quirky, GE, and Anthony from Boston.

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Fritzing Is Back, And This Time It’s Written In JavaScript!

Fritzing has been stuck in the mud for just over a year now. There were no updates for many months, and members of the community wondered what was going on. Now, things might be turning around: Fritzing is being rebooted by community members, and there’s a roadmap of upcoming features.

The biggest takeaway from the GitHub discussion is that there simply aren’t enough developers for Fritzing. Fritzing is written in C++ and Qt, and there simply aren’t enough skilled devs to work on it. Future versions of Fritzing will be written in JavaScript.

Other developments in store for Fritzing include clearing out the number of open issues, making a new alpha, generally clean up the entire codebase, and prepare for a release. To that end, there’s also the Freetzing community to rebase the entire project with an emphasis on modularity.

Yes, Fritzing died a terrible death due to legal and funding issues. That still doesn’t mean Fritzing isn’t a valuable tool, though. With these new developments, and entirely new generation of hardware makers can dip their toes into the world of hardware development the easy way, and an entirely new generation of Open Source developers can work on making Fritzing the best tool it can be. There’s never been a better time to get started in Fritzing.

Hacking A Cheap EBay Frequency Counter

eBay is a wondrous land, full of Star Wars memorabilia in poor condition, old game consoles at insane markups, and a surprising amount of DIY electronics. [TheHWCave] found himself tinkering with a common frequency counter kit, and decided to make a few choice improvements along the way (Youtube link, embedded below).

The frequency counter in question is a common clone version of [Wolfgang “Wolf” Büscher]’s minimalist PIC design. Using little more than a PIC16F628 and some seven-segment displays, it’s a competent frequency counter for general use. Clone versions often add a crystal oscillator tester and are available on eBay for a fairly low price.

[TheHWCave] found that the modifications were less than useful, and developed a way to turn the tester components into a more useful signal preamp instead. Not content to stop there, custom firmware was developed to both improve the resolution and also add a tachometer feature. This allows the device to display its output in revolutions per minute as opposed to simply displaying in hertz. By combining this with an optical pickup or other RPM signal, it makes a handy display for rotational speed. If you’re unfamiliar with the theory, read up on our phototachometer primer. If you’re looking to modify your own kit, modified firmware is available on Github.

We’ve seen other eBay kit specials modified before. Being cheap and using commodity microcontrollers makes them a ripe platform for hacking, whether you just want to make a few tweaks or completely repurpose the device.

[Thanks to Acesoft for the tip!]

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