Aesthetic PCB Design Tips For Improved Functionality

Those of us hardware types that spend a lot of time designing PCBs will often look at other peoples’ designs with interest, and in some cases, considerable admiration. Some of their boards just look so good. But are aesthetics important? After all, for most products, the delicate electronic components on that PCB are tucked safely inside a protective enclosure. But, as [Phil’s Lab] explains, aesthetic PCB designs can lead to functional improvements, such that better-looking designs are also better performing, in terms of manufacturability (and therefore yield), electromagnetic compatibility (EMC), and several other factors that can be important.

First off, making a PCB easy to read and using sane placement of components and connections will speed up debugging by reducing errors. Keeping a consistent and not too-tight placement grid can give the pick and place machine an easier task, and reduce solder issues during reflow. But there are also more serious concerns, such as the enforcement of design partitionings — such as keeping analog circuits together and away from noisy power and digital areas — which can make the difference between functioning within specification, and failure.

The video goes into a few other interesting tips, one highlight is using a ground-tied PCB perimeter zone, with wavelength-of-interest via stitching. This will reduce EMC side emissions from the power plane, but also if you select an appropriate surface finish, and keep the solder mask open, you’ve got a free, full perimeter contact to ground your scope probe. Oh, and it looks good too.

Hackaday is no stranger to beautiful artistic PCBs, like the work of [Saar Drimer] and many others. But if one PCB doesn’t cut it for your needs, there’s always the ‘Oreo’ construction to consider.

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EMC Tutorial Puts You In The Loop

A student once asked his lab instructor why his amplifier was oscillating. After looking at it and noting the wild construction, the instructor remarked, “A better question would be why shouldn’t it oscillate?” The truth of it is, our circuits generate noise and especially if they are oscillating anyway. Distortion and nonlinearities generate harmonics and other component imperfections also contribute.

[FesZ Electronics] has a great video series about noise in switching power supplies and the latest talks about the hot loop. If you want to improve the noise performance of your next design, these videos are well worth watching. You can see the hot loop video below.

We really liked the homebrew noise probes. In addition to real-world probing. The video also observes circuit operation under simulation. Even if you don’t care about noise performance, there’s a lot of good information about basic switching power supply design here.

You can see the difference in a PCB that has a small hot loop versus a very small hot loop. Something to think about next time you are laying out a power supply board.

If you want to dive deeper into noise simulation, we have a good read on that for you. Or ditch simulation, and make your own cheap probe with an SDR dongle.

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Hackaday Links: September 12, 2021

The last thing an astronaut or cosmonaut on the International Space Stations wants to hear from one of their crewmates is, “Do you smell plastic burning?” But that’s apparently what happened this week aboard the increasingly problematic spacecraft, as the burning smell and visible smoke spread from the Russian Zvezda module to the American side of town. The reports say it occurred while charging the station’s batteries, and we all know how dicey that can get. But apparently, the situation resolved itself somehow, as normal operations continued soon after the event. Between reports of cracks, air leaks, problems with attitude control, and even accusations of sabotage, the ISS is really starting to show its age.

Speaking of burning and batteries, normally a story about burning Tesla batteries wouldn’t raise our eyebrows much. But this story out of California introduces a potential failure mode for Tesla batteries that we hadn’t considered before. It seems a semi-truck with a load of Tesla batteries lost its brakes on Interstate 80 in the Sierra Nevada mountains and ended up flipping across the highway. Video from the scene shows the cargo, which looks like replacement batteries or perhaps batteries salvaged from wrecked cars, scattered across the highway on their shipping pallets. A fire was reported, but it’s not clear whether it was one of the batteries which had gotten compromised in the crash, or if it was something other than the batteries. Still, we hadn’t considered the potential for disaster while shipping batteries like that.

Attention all GNURadio fans — GRCon21 is rapidly approaching. Unlike most of the conferences over the last year and half, GRCon21 will actually be both live and online. We always love the post-conference dump of talks, which cover such a wide range of topics and really dive deeply into so many cool areas. We’re especially looking forward to the SETI talks, and we’re pleased to see our friend Hash, who was on the Hack Chat a while back, scheduled to talk about his smart-meter hacking efforts. The conference starts on September 20 and is being held in Charlotte, North Carolina, and virtually of course. If you attend, make sure to drop tips to your favorite talks in the tips line so we can share them with everyone.

We got a tip this week on a video about how 1/4-wave tuning stubs work. It’s a simple demonstration using a length of coax, a signal generator, and an oscilloscope to show how an unterminated feedline can reflect RF back to the transmitter, and how that can be used to build super-simple notch filters and impedance transformers. We love demos that make the mysteries of RF a little simpler — W2AEW’s videos come to mind, like this one on standing waves.

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Make Some Noise Or Simulate It, At Least

Noise is a fact of life, especially in electronic circuits. But on our paper schematics and just as often our simulations, there is no noise. If you are blinking an LED on a breadboard, you probably don’t care. But if you are working on something meatier, handling electrical noise gracefully is important and simulation can help you. [Ignacio de Mendizábal] has a great piece on simulating EMC filters using LTSpice that can get you started.

There are many ways of classifying noise and [Ignacio] starts with common-mode versus differential noise, where common-mode is noise with current flowing in the same direction without regard to the circuit’s normal operation, and differential noise having currents that flow in the opposite direction of normal current flow.

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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 DIY EMC Probe From Semi-Rigid Coax And An SDR

Do you have an EMC probe in your toolkit? Probably not, unless you’re in the business of electromagnetic compatibility testing or getting a product ready for the regulatory compliance process. Usually such probes are used in anechoic chambers and connected to sophisticated gear like spectrum analyzers – expensive stuff. But there are ways to probe the electromagnetic mysteries of your projects on the cheap, as this DIY EMC testing setup proves.

As with many projects, [dimtass]’ build was inspired by a video over on EEVblog, where [Dave] made a simple EMC probe from a length of semi-rigid coax cable. At $10, it’s a cheap solution, but lacking a spectrum analyzer like the one that [Dave] plugged his cheap probe into, [dimtass] went a different way. With the homemade probe plugged into an RTL-SDR dongle and SDR# running on a PC, [dimtass] was able to get a decent approximation of a spectrum analyzer, at least when tested against a 10-MHz oven-controlled crystal oscillator. It’s not the same thing as a dedicated spectrum analyzer – limited bandwidth, higher noise, and not calibrated – but it works well enough, and as [dimtass] points out, infinitely hackable through the SDR# API. The probe even works decently when plugged right into a DSO with the FFT function running.

Again, neither of these setups is a substitute for proper EMC testing, but it’ll probably do for the home gamer. If you want to check out the lengths the pros go through to make sure their products don’t spew signals, check out [Jenny]’s overview of the EMC testing process.

[via RTL-SDR.com]

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Hackaday Links: February 11, 2018

Are you a student? Are you part of a hackerspace? We have a contest going on right now where you can win a fancy new Prusa i3 MK3. The Repairs You Can Print contest is a challenge to do something useful with that machine that spits out tugboats. We’re looking for functional repairs of items around your house, office, or garage. Did you repair something with a 3D printer? Then you too can get in on the action! Enter now! Check out the entries!

You may know Flite Test as the group who do everything surrounding remote control flight (mostly fixed wings, a nice counter to the quadification of the hobby over the last few years). Flite Test designs and sells airplanes made out of Dollar Tree foam board, they have yearly, bi-coastal meetups, and they’re all-around awesome dudes. Now, they want to build the Disneyland of RC flight. [Josh Bixler], the face of Flite Test and a guy who has a plane named after him, wants to buy a golf course and turn it into the world’s best RC flying park, with a ~2000 foot grass strip for general aviation. We’re looking at their crowdfunding campaign, and it looks promising it might be funded by the time this goes live.

A while ago, [Peter Jansen], the guy who built a tricorder and a laser-cut CT scanner, made a magnetic camera. This Hall Effect camera is a camera for magnetism instead of light. Now, this camera has been fully built and vastly improved. He’s capturing ‘frames’ of magnetism in a spinning fan at 2000 Hz (or FPS, terminology kind of breaks down here), and it’s beautiful.

Oh thank God we can finally buy GPUs again. Try buying them with Bitcoin.

In the last few years, CITES, the Convention on International Trade in Endangered Species of Wild Fauna and Flora, has expanded. Originally, this was one of the treaties that banned the import or export of rhino horn, but recently this expanded to the export of rosewood thanks to increased demand in China for rosewood furniture. The laws of unintended consequences kicked into effect, and importing anything made out of rosewood is now a mess of permits and inspections at the border, including musical instruments. Travelling orchestras, for example, are at risk of having their string section confiscated because of rosewood tuning pegs. Cooler minds may now be prevailing, and there’s some hope the regulations may be changed during the next meeting of the CITES convention next year.

As noted a few months ago, there was a possibility of Broadcom buying Qualcomm for one… hundred… Billion dollarsThis offer was rejected, with Qualcomm saying the offer wasn’t high enough. Broadcom fired back with an offer of $82 per share, or $121B. This offer was rejected this week.

Need some EMC testing? [Zach]’s got your back. He’s reserved some time in a 10m EMC chamber for testing NeuroBytes this week. If you have an Open Source project that needs a pre-test scan for unintentional radiator, you can get in on the action. This is just a pre-test, you’re not getting certification, and you’re not going to test anything with radios, and you need to ship [Zach] your stuff. But still, free test time. Woo.