This Vibrating Continuity Tester Is Quietly Useful

Continuity testing is one of the most valuable functions on the modern multimeter. It will help you investigate wiring problems in your car, tell you if you’re holding a nullmodem serial cable or the regular kind, and even reveal when you’ve accidentally shorted the data lines right to the power supply. However, all that beeping can get annoying, so [bitelxux] built a vibrating version instead.

The build was borne out of necessity; [bitelxux]’s meter lacked a buzzer, and it grew frustrating to always look at the display. In order to allow late night hacking sessions to go on undisturbed, an unobtrusive vibrating tester was desired, as opposed to the usual audible type. Two whiteboard markers donated their shells to the hack, fitted with small nails to act as probes. Inside, a pager vibration motor is connected, vibrating when continuity is found. The circuit runs from a 1.5V AA battery which neatly fits inside the marker shell.

It’s a basic build, but gets the job done with a minimum of fuss using parts that most makers probably have lying around. Of course, you can always go a slightly more complicated route and throw an Attiny at the problem.

Hackaday Meetup: Shenzhen

Hackaday and Seeed Studio are hosting a meetup in Shenzhen on Friday, March 22nd and you are invited!

This meetup is happening at X.factory, a maker hub run by Seeed Studios. Sophi Kravitz and Mike Szczys will be in town for the meetup and will both speak, along with a project talks from members of the Hackaday Community. Snacks and beverages will be served, and as always, if you have a project you’re working on bring it along! Having a piece of hardware is a great way to start a conversation, and this is the perfect place to draw inspiration, seek advice from your peers, and find team members to join in your projects!

Come and celebrate a love for design, electronics, learning new things, and meeting new people. We hope to see you at X.factory next week!

Learn Digital Logic By Alien Abduction

Some of the best educational material we’ve seen tells a story. There’s something more fun about reading a story than just absorbing a bunch of dry facts. That’s the idea behind Adventures in Logic Land. In the first episode, you are abducted by aliens trying to decide if humans are intelligent. To prove that, you have to work a series of logic puzzles.

The approach is a little unorthodox. You are shown a live logic simulation (spoiler: it is a NOR gate) and you have to fill in a truth table. The gates use alien symbols which contributes to the storyline but perhaps isn’t the best choice from an educational perspective. Besides, they already use red for zero and green for one which seems a little culturally-specific. The next test shows you how to build your own little simulations and run tests to see if they meet the alien’s criteria.

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An HDMI Input For A Laptop Screen, Minus Laptop

The lack of HDMI inputs on almost all laptops is a huge drawback for anyone who wants to easily play a video game on the road, for example. As to why no manufacturers offer this piece of convenience when we all have easy access to a working screen of this size, perhaps no one can say. On the other hand, if you want to ditch the rest of the computer, you can make use of the laptop screen for whatever you want.

This project from [Avner] comes to us in a few parts. In the first section, the teardown of the laptop begins and a datasheet for the screen is discovered, which allows [Avner] to prepare an FPGA to drive the screen. The second part involves building an HDMI sink, which is a device which decodes the signal from an HDMI source into its constituent parts so it can be sent to the FPGA. The final section of the project involves actually sending a video to this impressive collection of hardware in order to get a video to appear on the old laptop screen.

This build is worth checking out if you’ve ever dealt with anything involving digital video. It goes into great depth on a lot of the technical details involving HDMI, video devices, and hardware timing issues. This is a great build and, even though we’ve seen similar projects, definitely worth diving into if you have some time on your hands and a spare laptop screen.

Downdraft Table Inhales Dust, Not Cash

We always look forward to the builds [MakerMan] sends in, and it’s not just because we dig his choices in royalty free music (though it helps). He always manages to put together his projects with a minimum of fuss, and perhaps more importantly, a minimum of funds. His builds use salvaged components, easily sourced materials, and common tools. Watching him work invariably makes us realize that we tend to overthink our own projects.

In his latest video, [MakerMan] was tasked with building a downdraft table for a local factory that makes jewelry boxes. By sucking air through a series of holes in the table’s surface, sawdust created while the workers are building the boxes will automatically be removed from the workspace. Even if you aren’t in the jewelry box making business, any task which produces fine particles (such as sanding) could benefit from such a setup. You probably won’t need a downdraft table quite as large as the one he builds, but the principles will be the same if you get inspired to build a somewhat smaller version.

The build starts with sheets of MDF, which get cut, glued, and screwed together to make the basic tabletop shape. To this, [MakerMan] attaches a welded steel frame which will give it the strength MDF itself lacks. With careful measurement, lines are plotted across the top of the MDF sheet and all the holes are drilled with a simple hand drill; no fancy CNC here.

With the table doing its best colander impression, [MakerMan] adds an air box to the bottom which is similarly made of thin MDF sheets. All of the joints are sealed up with caulk, because at this point you want things to be as air tight as possible. A large blower is attached to the bottom, which gets piped to a dust collection system that’s made of a garbage can and…you guessed it, more MDF.

Watching [MakerMan] turn what’s often literal trash into a functional build never gets old. We’ve seen him create everything from a gorgeous origami chandelier to a very impressive diode laser cutter using little more than scrap parts and hand tools, and we can’t wait to see what he comes up with next.

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Wood SCARA Arm Gets a Grip

[Ignacio]’s VIRK I is a robot arm of SCARA design with a very memorable wooden body, and its new gripper allows it to do a simple pick and place demo. Designing a robot arm is a daunting task, and the fundamental mechanical design is only part of the whole. Even if the basic framework for a SCARA arm is a solved problem, the challenge of building it and the never-ending implementation details make it a long-term project.

When we first saw VIRK I in all its shining, Australian Blackwood glory, it lacked any end effector and [Ignacio] wasn’t sure of the best way to control it. Since then, [Ignacio] has experimented with Marlin and Wangsamas support for SCARA arms, and designed a gripper based around a hobby servo. It’s as beautiful to see this project moving forward as it is to see the arm moving ping-pong balls around, embedded below.

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Expert Says Don’t Teach Kids to Code

I was a little surprised to see a news report about Andreas Schleicher, the director of education and skills at OECD — the Organization for Economic Cooperation and Development. Speaking at the World Innovation Summit for Education in Paris, Schleicher thinks that teaching kids to code is a waste of time. In particular, he seems to think that by the time a child today grows up, coding will be obsolete.

I can’t help but think that he might be a little confused. Coding isn’t going away anytime soon. It could, of course, become an even deeper specialty, and thus less generally applicable. But the comments he’s made seem to imply that soon we will just tell smart computers what we want and they will just do that. Somewhat like computers work on Star Trek.

What is more likely is that most people will be able to find specific applications that can do what they want without traditional coding. But someone still has to write something for the foreseeable future. What’s more, if you’ve ever tried to tease requirements out of an end user, you know that you can’t just blurt out anything you want to a computer and expect it to make sense. It isn’t the computer’s fault. People — especially untrained people — don’t always make sense or communicate unambiguously.

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