Let’s Play…Wheel of Solder!

Solder is solder right? Just spin the wheel and whatever comes up will work fine. Well, not so fast. If you’re new to electronics, or are looking at getting started, there is a bit to learn first. [Mr Carlson] has the info you need with this youtube video you can watch after the break.

He begins with a discussion of solder diameter. For most through hole work, something around 0.03 inch is pretty universal. When your ready to step up to SMD work, we find 0.02″ inch to be a much better match to the smaller pad sizes. [Mr Carlson] goes on to talk about the types of flux used inside the solder. Rosin(R), Rosin-Midly-Activated(RMA) and Rosin Activated(RA) in order of least to most aggressive.

He rounds out the video with information and a warning about using “organic” core solder. If you’re new to the world of solder, this video is a good jumping off point. TLDR; If you’re just starting out, a 0.03″ RMA solder would be a good place to start – but if you want to learn a bit more, the 20 minute video is worth the watch for those of you just getting your feet iron tip wet. It’ll serve you well at least until solderless metal glue becomes affordable.

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Finally, a Power Meter Without Nixies

We’ve had quite a spate of home-brew energy meters on the tip line these days, and that probably reflects a deep inner desire that hackers seem to have to quantify their worlds. Functionally, these meters have all differed, but we’ve noticed a distinct stylistic trend toward the “Nixies and wood” look. Ironically, it is refreshing to see an energy meter with nothing but a spartan web interface for a change.

Clearly, [Tomasz Salwach] had raw data in mind as a design goal, and his Raspberry Pi-based meter delivers. After harvesting current sensing transformers from a bucket of defunct power meter PC boards, [Tomasz] calibrated them with a DIY oscilloscope and wired them and the voltage sensors up to an STM32 Nucleo development board. Data from the MCU goes to the Pi for processing and display as snazzy charts and GUI elements served internally. [Tomasz] was kind enough to include a link to his meter in his tip line post, but asked that we not share it publicly lest HaD readers love the Pi to death. But we can assure you that it works, and it’s kind of fun to peek in on the power usage of a house in Poland in real time.

It’s a nice project that does exactly what it set out to do. But if you missed the recent spate of Nixie-based displays, check out this front hallway meter or this one for a solar-power company CEO’s desk.

The Toy Maker

A large part of the world still educates their kids using a system that’s completely antiquated. Personal choices and interests don’t matter, and learning by rote is the norm. Government schooling is woefully inadequate and the teachers are just not equipped, or trained, to be able to impart useful education. [Arvind Gupta], a science educator, is trying to change this by teaching kids how to build toys. His YouTube channel on Toys for Science and Math Education has almost 100,000 subscribers and over 44 million views. It’s awesome.

matchstickmecanno01[Arvind] graduated from one of the finest engineering schools in India, the Indian Institute of Technology in Kanpur, and joined the TATA conglomerate at their heavy-vehicles plant helping build trucks. It didn’t take him long to realize that he wasn’t cut out to be building trucks. So he took a year off and enrolled in a village science program which was working towards changing the education system. At the weekly village bazaar, he came across interesting pieces of arts and crafts that the villagers were selling. A piece of rubber tubing, used as the core of the valve in bicycle tubes, caught his eye. He bought a length and a couple of matchboxes, and created what he calls “matchstick Meccano”.

This was in the 1970’s. Since then, he has been travelling all over India getting children to learn by building fun toys. The toys he designs are made from commonly available raw material and can be easily built with minimum resources. These ingenious DIY toys and activities help make maths and science education fun and interesting for children at all levels of schooling. All of his work is shared in the spirit of open source and available via his website and YouTube channels. A large body of his work has been translated in to almost 20 languages and you are welcome to help add to that list by dubbing the videos.

Check out the INK Conference video below where he shares his passion for education and shows simple yet entertaining and well-designed toys built from trash and recycled materials.

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Fixing Broken Monitors By Shining A Flashlight

[dyril] over on the EEVblog has a broken LED TV. It’s a fairly standard Samsung TV from 2012 that unfortunately had a little bit of corrosion on the flexible circuit boards thanks to excessive humidity. One day, [dyril] turned on his TV and found about one-third of the screen was glitchy. After [dyril] took the TV apart, an extremely strange fix was found: shining a light on the corroded flexible circuit board fixed the TV.

The fix, obviously, was to solder a USB light to a power rail on the TV and hot glue the light so it shines on the offending circuit. Solving a problem is one thing, though, understanding why you’ve solved the problem is another thing entirely. [dyril] has no idea why this fix works, and it’s doubtful anyone can give him a complete explanation.

The TV is fixed, and although you can’t argue with results, there is a burning question: how on Earth does shining a light on a broken circuit board fix a TV? Speculation on the EEVblog thread seems to have settled on something similar to the photonic reset of the Raspberry Pi 2. In the Raspberry Pi 2, a small chip scale package (CSP) used in the power supply section would fail when exposed to light. This reset the Pi, and turned out to be a very educational introduction to photons and energy levels for thousands of people with a Pi.

The best guess from the EEVblog is that a chip on the offending board handles a differential signal going to the flex circuit. This chip is sensitive to light, and shutting it down with photons allows the other half of the differential signal to take over. It’s a hand-wavy explanation, but then again this is a very, very weird problem.

You can check out [dyril]’s video demonstration of the problem and solution below. Thanks [Rasz] for sending this one in.

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How to Use Lidar with the Raspberry Pi

The ability to inexpensively but accurately measure distance between an autonomous vehicle or robot and nearby objects is a challenging problem for hackers. Knowing the distance is key to obstacle avoidance. Running into something with a small robot may be a trivial problem but could be deadly with a big one like an autonomous vehicle.

My interest in distance measurement for obstacle avoidance stems from my entry in the 2013 NASA Sample Return Robot (SRR) Competition. I used a web camera for vision processing and attempted various visual techniques for making measurements, without a lot of success. At the competition, two entrants used scanning lidars which piqued my interest in them.

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Link Trucker is a Tiny Networking Giant

If you’re a networking professional, there are professional tools for verifying that everything’s as it should be on the business end of an Ethernet cable. These professional tools often come along with a professional pricetag. If you’re just trying to wire up a single office, the pro gear can be overkill. Unless you make it yourself on the cheap! And now you can.

[Kristopher Marciniak] designed and built an inexpensive device that verifies the basics:

  • Is the link up? Is this cable connected?
  • Can it get a DHCP address?
  • Can it perform a DNS lookup?
  • Can it open a webpage?

What’s going on under the hood? A Raspberry Pi, you’d think. A BeagleBoard? Our hearts were warmed to see a throwback to a more civilized age: an ENC28J60 breakout board and an Arduino Uno. That’s right, [Kristopher] replicated a couple-hundred dollar network tester for the price of a few lattes. And by using a pre-made housing, [Kristopher]’s version looks great too. Watch it work in the video just below the break.

Building an embedded network device used to be a lot more work, but it could be done. One of our favorites is still [Ian Lesnet’s] webserver on a business card from way back in 2008 which also used the ENC28J60 Ethernet chip.
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The Trouble With Intel’s Management Engine

Something is rotten in the state of Intel. Over the last decade or so, Intel has dedicated enormous efforts to the security of their microcontrollers. For Intel, this is the only logical thing to do; you really, really want to know if the firmware running on a device is the firmware you want to run on a device. Anything else, and the device is wide open to balaclava-wearing hackers.

Intel’s first efforts toward cryptographically signed firmware began in the early 2000s with embedded security subsystems using Trusted Platform Modules (TPM). These small crypto chips, along with the BIOS, form the root of trust for modern computers. If the TPM is secure, the rest of the computer can be secure, or so the theory goes.

The TPM model has been shown to be vulnerable to attack, though. Intel’s solution was to add another layer of security: the (Intel) Management Engine (ME). Extremely little is known about the ME, except for some of its capabilities. The ME has complete access to all of a computer’s memory, its network connections, and every peripheral connected to a computer. It runs when the computer is hibernating, and can intercept TCP/IP traffic. Own the ME and you own the computer.

There are no known vulnerabilities in the ME to exploit right now: we’re all locked out of the ME. But that is security through obscurity. Once the ME falls, everything with an Intel chip will fall. It is, by far, the scariest security threat today, and it’s one that’s made even worse by our own ignorance of how the ME works.

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