DIY Watertight Junction Box For Serious Outdoor Sealing

September 10, 2019 by 32 Comments

Thingiverse user [The-Mechanic] shared a design for 3D printed enclosures that are made to house wire and cable junctions, which can then be rendered weatherproof by injecting them with a suitable caulking compound and allowing it to cure. It’s a cross between an enclosure and potted electronics. It’s also a one-way trip, because the result is sealed up like a pharaoh’s tomb. On the upside, it’s cheap, accessible, and easily customized.

The way it works is this: wires go through end caps which snap onto the main body, holding the junction inside. Sealant is then pumped in via the hole on the side, then the hole is plugged. Afterwards, all there is to do is wait until the sealant cures. [The-Mechanic] has a couple of companion designs, as well. For tubes of sealant that have threaded tops, one can more effectively save the contents of the tube for later with this design for screw-on caps. There are also 3D printed nozzles in a variety of designs.

One thing to keep in mind about silicone-based sealants is that thick gobs of it can take a really, really long time to cure fully. A thick gob of the stuff will tend to firm up on the outside but leave the inside gooey. If that will be a problem, maybe take a cue from Oogoo and mix in a bit of corn starch with the silicone sealant. The resulting mixture will be thicker, but it’ll cure throughout with no problems.

Digital Oscilloscope Does Its Best Analog Impression

September 10, 2019 by 48 Comments

Do you ever find yourself yearning for the days before digital storage oscilloscopes (DSOs)? Where even the basic scopes commanded four figures, and came in a bench-dominating form factor? No, of course you don’t. The DSO is a wonder of modern technology: for a couple hundred bucks you can have capabilities that previously would have been outside the reach of hobbyists, all in a package that’s small enough to fit on even the most cramped workbenches.

Which is why the good folks of the EEVblog forums are so confused about the OWON AS101, a modern digital oscilloscope that’s designed to look and operate like the analog CRT monsters of old. Despite the 3.7 inch LCD, users are treated to the classic analog scope look, and the switches and knobs on the front should trigger a wave of nostalgia for hackers of a certain age.

But this isn’t just some “retro” look-alike, OWON is committed to delivering on that analog experience by taking away all those modern digital features we’ve become so dependant on. This single-channel scope can’t save data to USB, doesn’t have any sort of protocol decoding capabilities, and forget about automatic…well, anything. It’s even limited to 20 MHz, just like the old-school CRT scopes that you pick up for a song at any swap meet. All for the low, low, price of $150 USD from the usual importers.

In the EEVblog thread, the best idea anyone can come up with is that the OWON AS101 is designed for educational markets in developing countries, where outdated equipment is so common that there may actually be a need for faux-analog oscilloscopes to match what’s already in use. These new-manufactured “analog” trainers can be used to get students ready for a professional life of using antiquated technology. It’s hard to believe, but sometimes we can forget how fortunate many of us are to have easy access to cheap tools and equipment.

Even still, when you can get a pocket-sized 10 MHz DSO for around $50, it’s difficult to imagine how this analog-digital hybrid could possibly attract any takers at 3x times the price. If any of our readers would care to shed some light on this unusual piece of gear, we’d love to hear it.

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Meet The 20 Finalists In The 2019 Hackaday Prize

September 10, 2019 by 7 Comments

The Hackaday Prize is our global engineering initiative, now in its sixth year. For 2019, the focus is on product development: with great engineering and a working prototype, can you also go the distance to embrace the user’s needs and ensure the project can be produced in quantity? Throughout the Spring and Summer we’ve been watching as hundreds step into the spotlight to share their projects with the world. Now we’re in the final stretch as these twenty entries all try to claim the grand prize of $125,000. Let’s take a look!

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Why Ada Is The Language You Want To Be Programming Your Systems With

September 10, 2019 by 168 Comments

The Ada programming language was born in the mid-1970s, when the US Department of Defense (DoD) and the UK’s Ministry Of Defence sought to replace the hundreds of specialized programming languages used for the embedded computer systems that increasingly made up essential parts of military projects.  Instead, Ada was designed to be be a single language, capable of running on all of those embedded systems, that offered the same or better level of performance and reliability.

With the 1995 revision, the language also targeted general purpose systems  and added support for object-oriented programming (OOP) while not losing sight of the core values of reliability, maintainability and efficiency. Today, software written in Ada forms the backbone of not only military hardware, but also commercial projects like avionics and air-traffic control systems. Ada code controls rockets like the Ariane 4 and 5, many satellites, and countless other systems where small glitches can have major consequences.

Ada might also be the right choice for your next embedded project. Continue reading “Why Ada Is The Language You Want To Be Programming Your Systems With” →

Because Conventional Laser Harps Aren’t Dangerous Enough

September 10, 2019 by 7 Comments

In the late 1980s, the French musician [Jean-Michel Jarre] famously toured with a laser harp. The word among teenage fans was that he had to wear special gloves to stop his hands getting burned, because 1980s teens were both impressionable and didn’t know much about lasers. In fact we’re told by a member of our community who was part of his road crew that the glove was a matter of reflectivity, so laser harps remain relatively harmless and French harpists retain their fingers. To add a bit of spice to the laser harp experience, [James Cochrane] hooked up a laser rangefinder to a Tesla coil to make an instrument with a bit more crackling energy in its performance than the [Jarre] model.

It starts with a laser tape measure modified to serve as an Arduino rangefinder, coupled to custom MIDI code to make a laser harp MIDI controller. The Tesla coil in question happens also to be a MIDI instrument, so the one can control the other with ease. The addition of an earthed chain mail glove allows it to be played in close proximity to the coil, and he rewards us with a rendition of the Star Trek theme. Tesla fun and games behind us, he then gives us a demonstration with a more conventional MIDI instrument.

We’ve had innumerable Tesla coil projects here over the years, if you’re hungry for more we suggest starting with this unusual planar PCB coil design. Meanwhile you can see the laser harp coil in the video below the break.

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Norovirus Smartphone: Using Megapixels And Microfluidics To Fight The Other Kind Of Virus Infection

September 10, 2019 by 8 Comments

Chances are pretty good that at some time in your life, you’ve crossed paths with a norovirus. And chances are that you remember the encounter vividly, or at least its aftermath. I recall a run-in with the bug one Christmas, when my parents brought over more than just toys for the kids when they visited. Within a day, everyone in the house was sharing the joy. Twas the season; they don’t call it the winter vomiting bug for nothing.

Most of the 685 million norovirus infections each year resolve after a few miserable days, but some require hospitalization and 200,000 of them result in death, mainly from dehydration and mainly children. An easy to use, cheap, and accurate means of detecting the virus in the field would be quite a boon to public health. And soon, smartphones may be able to do just that.

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Detecting Cars With An ESP8266 Magnetometer

September 10, 2019 by 28 Comments

Having a motorized gate on your driveway is great, but only if there’s an easy way to trigger it. [Andrew] says the gate at his parent’s place could only be controlled by manually pushing a button on the panel or with a dinky remote that didn’t have nearly the range they wanted. So he decided to build his own magnetometer allowing the gate to automatically open when a car was trying to leave.

Naturally, there are commercial offerings that would solve this problem. But with a sticker price of more than $150 USD, [Andrew] was more than happy to spend a bit of time tinkering to get the job done for less than 1/10th the cost with an ESP8266 and a QMC5883X series magneto-resistive sensor. Of course, this is one of those projects that seems simple enough in your head, but ends up taking a bit of finesse to pull off in the real-world.

For one, [Andrew] had to figure out how to prevent false positives. Pretty much any object brought close enough to the sensor, including his hand, would cause it to react. He ended up coming up with a way to use a rolling average to prevent the gate from firing off just because a squirrel ran past. The built-in safeties are designed to ensure that the gate only opens when an actual car is sitting in the appropriate spot for long enough.

Speaking of, we love how [Andrew] deployed the QMC5883X sensor for this project. The small sensor board and a few moisture-absorbing packets were placed in a Sonoff IP66 waterproof enclosure, and buried under the rocks of the driveway. A standard CAT5 cable is used to tether it to the ESP8266, relay, and assorted other goodies that now live in the gate’s control box. In the future he says the cable will likely have to go into a conduit, but for now the system is working more or less how he expected.

If your estate isn’t quite palatial enough to have a motorized gate out front, we’ve seen plenty of projects that add some much-needed intelligence to the humble garage door opener which might be more your speed.