Hackaday Links: June 25th, 2017

There will be no special badges for DEFCON. Everyone will still have badges — and our expectations are tempered because of the one year on / one year off schedule for electronic badges — there just won’t be mind-bending puzzles wrapped up in the official badges. What this means: it probably won’t matter if you’re late for linecon, and someone in the DEFCON hive mind still has a Facebook. Also, DEFCON is canceled.

In the past, we have decried the very existence of fidget spinners. It’s what the kids are into, after all. However, an electronic fidget spinner is an interesting engineering challenge. It combines the mechanical fun of bearing science, the exacting precision of balancing stuff, and stuffing electronics where no electronics should be. This Kickstarter is perhaps the best electronic fidget spinner we’ve seen. The electronics are powered by a coin cell and are packed into one of the spaces for the ‘wing’ bearings, and two additional weighted bearings allow the spinner to balance. There’s a small magnet for a hall effect sensor in the ‘stator cap’ so RPM can be measured. This design uses the most common mold for a fidget spinner, making it very manufacturable. Compare this design to the Internet of Fidget Spinners, a POV fidget Spinner, another POV fidget spinner, an educational electronic fidget spinner, or this amazing technique to measure the speed of a fidget spinner that will blow your mind, and you’ll see this Kickstarter project is clearly the superior design.

You kids are spoiled with your programmable drum machines like your 808 and 909. Back in the day, drum machines were attached to organs, and only had a few patterns. You couldn’t change the patterns, you could only change the speed. [Jan] has created one of these prehistoric drum machines in a microcontroller. You get hard rock, disco, reggae, rock, samba, rumba, cha-cha, bossa nova, beguine, synthpop, boogie, waltz, jazz rock, and slow rock. Awesome.

There’s a new electronics magazine. It’s called DIYODE, and we’re all kicking ourselves for not coming up with that name.

Do you need a new password? Humans really aren’t good at coming up with random numbers, and if you need a completely random alphanumeric password, it’s best left to a computer. Have no fear, because there’s now a website that generates the single most secure password on the planet. This password, “H4!b5at+kWls-8yh4Guq”, features upper and lowercase characters, numbers, symbols, and twenty unique characters. This password was developed by security researchers and encryption specialists in Europe, so you know it has absolutely nothing to do with the NSA, CIA, or any other American three-letter agency.

Speaking of three-letter agencies, last Wednesday was International Selfie Day! That doesn’t mean you still can’t get in on the action. Take a selfie right now and upload it to social media! What’s facial recognition?

Looking for a great little ESP32 breakout board with all the bells and whistles? Olimex has a new board out with Ethernet, a MicroSD card slot, and 20 GPIOs broken out.

Fail of the Week: Tracking Meteors with Weather Radio

It’s not hard to detect meteors: go outside on a clear night in a dark place and you’re bound to see one eventually. But visible light detection is limiting, and knowing that meteors leave a trail of ions means radio detection is possible. That’s what’s behind this attempt to map meteor trails using broadcast signals, which so far hasn’t yielded great results.

Passing jet’s Doppler signature

The fact that meteor trails reflect radio signals is well-known; hams use “meteor bounce” to make long-distance contacts all the time. And using commercial FM broadcast signals to map meteor activity isn’t new, either — we’ve covered the “forward scattering” technique before. The technique requires tuning into a frequency used by a distant station but not a local one and waiting for a passing meteor to bounce the distant signal back to your SDR dongle. Capturing the waterfall display for later analysis should show characteristic patterns and give you an idea of where and when the meteor passed.

[Dave Venne] is an amateur astronomer who turns his eyes and ears to the heavens just to see what he can find. [Dave]’s problem is that the commercial FM band in the Minneapolis area that he calls home is crowded, to say the least. He hit upon the idea of using the National Weather Service weather radio broadcasts at around 160 MHz as a substitute. Sadly, all he managed to capture were passing airplanes with their characteristic Doppler shift; pretty cool in its own right, but not the desired result.

The comments in the RTL-SDR.com post on [Dave]’s attempt had a few ideas on where this went wrong and how to improve it, including the intriguing idea of using 60-meter ham band propagation beacons. Now it’s Hackaday’s turn: any ideas on how to fix [Dave]’s problem? Sound off in the comments below.

Amazing Motion-Capture of Bendy Things

Have you, dear reader, ever needed to plot the position of a swimming pool noodle in 3D  and in real time? Of course you have, and today, you’re in luck! I’ve compiled together a solution that’s sure to give you the jumpstart on solving this “problem-you-never-knew-you-had.”

Ok, there’s a bit of a story behind this one. Back in my good-ol’ undergrad days, I got the chance to play with tethered underwater robots. I remember fumbling about thinking: “Hmm, with this robot tether, wouldn’t it be sweet to string up a set of IMUs down the length of the tether to estimate the robot’s location in 3-space?” A few years later, I cooked together this IMU Noodle project to play with some real hardware in the spirit of solving that problem. With a little quaternion math, a nifty IMU, and some custom PCBAs, this idea has gone from some idle brain-ramble into a real device. It’s an incredibly interesting example of using available hardware and a little ingenuity to build a system that is unique and dependable.

As for why? I first saw an IMU noodle pop up on these pages back in 2012 and I was baffled. I just had to build one! Now complete, I figured that there’s enough math and fun-loving electronics nuggets to merit a full article for this month’s after-hour adventures. Dear reader, let me tell you a wonderful story where math meets electronics and works up the courage to ask it out for brunch.

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Ask Hackaday: SawStop — Bastion of Safety or Patent Troll

At first glance, SawStop seems like a hacker’s dream. A garage tinkerer comes up with a great idea, builds a product around it, and the world becomes a better place. As time has gone on, other companies have introduced similar products. Recently, SawStop successfully stopped Bosch from importing saws equipped with their Reaxx safety system into the USA. This not only impacts sales of new saws, but parts for existing equipment. Who gets screwed here? Unfortunately, it’s the owners of the Bosch saws, who now have a safety feature they might not be able to use in the future. This has earned some bad press for SawStop in forums and on websites like Reddit, where users have gone as far as to call SawStop a patent troll. Is that true or just Internet puffery? Read on and decide for yourself.

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Panelizing Boards The Easy Way

For reasons that will remain undisclosed until some time in the future, I recently had a need to panelize a few PCBs. Panelization is the art of taking PCB designs you already have, whether they’re KiCad board files, Eagle board files, or just Gerbers, and turning them into a single collection of PCBs that can be sent off to a fab house.

Now this is panel racing

If you’re still wondering what this means, take a look at the last board you got from OSH Park, Seeed, Itead, or Dirty PCBs. Around the perimeter of your board, you’ll find some rough spots. These are ‘mouse bites’ and tabs, places where the boards are strung together to form a gigantic rectangular panel sent off to a manufacturer. You can check out this great interview with [Laen] from OSH Park to get an idea of how this works, but the basic process is to take a bunch of Gerbers, add tabs and mouse bites, solve the knapsack problem, and send the completed panel off to a board house.

Panelizing boards is something most of us won’t have to do often. Really, you only want a panel of boards when you’re manufacturing something. For small-scale production and prototypes, bare boards will do just fine. Simply by virtue of the fact that panelizing boards is far less common than throwing some Gerbers at OSH Park or Seeed, there aren’t many (good) tutorials, and even fewer (good) tools to do so. This is how you panelize boards quickly and easily using Open Source tools.

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Friday Hack Chat: Perfect Purple PCBs

Every Friday, we gather ’round the hot air gun over on Hackaday.io, invite some cool people over, and get them to talk about what they do. This is the Hack Chat. It’s become a tradition, and already we’ve had a ton of awesome people walk through our doors.

This Friday, we’re going to sit down with the purveyors of perfect purple PCBs. Over the last decade or so, a lot has changed in the space of small-run PCB production. Ten years ago, PCBs were expensive, and it wouldn’t be abnormal to spend hundreds of dollars on a small run of tiny boards. Now, The DEF CON 24 badge, in a panel are cheaper than ever, giving industrious hardware creators access to professional quality manufacturing at a fraction of the price seen just a few years ago.

For the last few years, OSH Park has been a mainstay of low-volume PCB fabrication. Their website is as simple as it gets: Upload some Gerbers, an Eagle board file, or a KiCad PCB, press a few buttons, and in a week or so you’ll have a perfect purple PCB in your mailbox.

This week, we’re inviting [Drew Fustini] and [Dan Sheadel] to talk about what OSH Park does, how they became the first place that comes to mind when you need a PCB. They’ll explain why the boards are purple, environmental regulations for PCB manufacturing in the US, shared projects and tips and tricks for creating the perfect board.

What would you like to see from a PCB supplier? Would you like to see OSH Park expand further into their burgeoning Pog business? How about a sticker club? Who would win in a fight, a blue robot dog or a purple robot shark? All these questions and more will be answered; if you have a question for the OSH Park team, drop it in this spreadsheet.

Here’s How To Take Part:

join-hack-chatOur Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This hack chat will take place at noon Pacific time on Friday, June 23rd. Confused about where and when ‘noon’ is? Here’s a time and date converter!

Log into Hackaday.io, visit that page, and look for the ‘Join this Project’ Button. Once you’re part of the project, the button will change to ‘Team Messaging’, which takes you directly to the Hack Chat.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about

MRIs: Why Are They So Loud?

My dad was scheduled for his first MRI scan the other day, and as the designated family technical expert, Pop had plenty of questions for me about what to expect. I told him everything I knew about the process, having had a few myself, but after the exam he asked the first question that everyone seems to ask: “Why is that thing so damn loud?”

Sadly, I didn’t have an answer for him. I’ve asked the same question myself after my MRIs, hoping for a tech with a little more time and lot more interest in the technology he or she uses to answer me with more than the “it’s the machine that makes the noise” brush-off. Well, duh.

MRI is one of those technologies that I don’t feel I have a firm enough grasp on, and it seems like something I should really be better versed in. So I decided to delve into the innards of these modern medical marvels to see if I can answer this basic question, plus see if I can address a few more complicated questions.

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