Two Portable Oscilloscopes: Shootout

January 28, 2016 by Al Williams 3 Comments

Last time I introduced you to two relatively inexpensive and somewhat portable scopes: the EM125, which is a cross between a digital voltmeter and an oscilloscope, and the Wave Rambler, which is a scope probe with a USB connector attached. Both of the devices cost about $100, and both have their plusses and minuses.

This time, though, I wanted actually to look at some real-world signals. To make that easy, I grabbed yet another scope-like thing I had handy: an Embedded Artists Labtool. This is an interesting board in its own right. It is an LPC-Link programmer attached to an LPC ARM board that has several high-speed A/D channels. However, I’m not using any of that capability for now. The board also has a cheap ARM processor (an LPC812) on it that serves only to generate test signals. The idea is you can use the Labtool in a classroom with no additional equipment.

The Labtool’s demo CPU generates a lot of different signals, but with only one channel on the test scopes, it didn’t make sense to look at, for example, I2C data. So I stuck with two different test signals: a varying pulse width modulation signals and a serial UART transmitter.

Continue reading “Two Portable Oscilloscopes: Shootout” →

Homemade Bulletproof Glass, Built And Tested

January 28, 2016 by Dan Maloney 35 Comments

Hackers tend to stash away lots of stuff that seems useless, right up until it saves the day. This includes not just junk in our parts bin but brains full of tips and tricks for the shop. With that in mind, you might want to file away a few of the tips in [AvE]’s video of how he made bulletproof glass for a rainy day.

By his own admission, [AvE]’s video is a little disjointed, and the topic of the bulletproof glass is only covered at the beginning and again briefly at the end. Most of the video concerns the machining of a stout stand for the glass for testing on the range. There’s plenty to learn from the machining, though, and [AvE] is always good for a laugh, so the video is worth a watch. The bulletproof glass itself is part of a long-term project that [AvE] is releasing first to his Patreon patrons – a ridiculously over-built flashlight dubbed “The Midnight Sun”. His first two tries at laminating the Lexan discs were less that optimal, as both brands of cyanoacrylate glue clouded the polycarbonate. Stay tuned to the end of the video for the secret of welding Lexan together into an optically clear sandwich.

As for testing under fire, [AvE] sent the rig off to buddy [TAOFLEDERMAUS] for the hot lead treatment. The video after the break shows that the glass is indeed bulletproof, as long as the bullet in question is a .22LR. Not so much for the 9mm, though – that was a clear punch-through. Still, pretty impressive performance for homebrew.

If you want something that can stop an arrow, there’s a lot of materials science to be learned from the ancient Greeks.

Continue reading “Homemade Bulletproof Glass, Built And Tested” →

Beautiful And Bizarre Boards

January 28, 2016 by Nava Whiteford 49 Comments

weirdboard — An odd board (piezo coupler), fabbed by OSHPark.

Recently I’ve been getting curious about interesting PCB shapes. In the past I’ve always used simple Polygons, perhaps rounding out the corners to make the design a little more aesthetically pleasing. The board to the right was my introduction to the possibilities of oddly shaped boards. It’s designed to couple with a piezo buzzer (used as an actuator). I’ve been planning to have it fabricated out of FPC (Flexible Printed Circuits), but with fabrication being so cheap I sent it to OSHPark to see what they’d make of it. OSHPark doesn’t have hard specs around internal routing, but in my experience they’re up to try anything (and they’re quality is always great). The width of the prongs on the PCB shown is 5mm. I figured it was a risk, and that it was likely the FR4 could break, but it came back great!

This has led me to the realization that my boards could look much more exciting than they do currently, and that our highly optimized modern PCB fabrication process provides a lot of room for experimentation. This article will discuss some of the options available when creating non-traditional PCBs.

Continue reading “Beautiful And Bizarre Boards” →

Rube Goldberg PC/Console Game Hack

January 28, 2016 by Elliot Williams 19 Comments

There’s no holy war holier than establishing whether PC games are superior to console games (they are). But even so, there’s no denying that there are some good console titles out there. What if you’d still like to play them using a mouse and keyboard? If you’re [Agent86], you’d build up the most ridiculous chain of fun electronics to get the job done.

Now there is an overpriced off-the-shelf solution for this problem, and a pre-existing open-source project that’ll get the same job done for only a few bucks in parts. But there’s nothing like the fun in solving a problem your own way, with your own tangle of wires, darn it all! The details of the build span four (4!) pages in [Agent86]’s blog, so settle down with a warm cup of coffee.

Here’s the summary: an Xbox 360 controller is taken apart and turned into an Xbox controller. The buttons and joysticks are put under computer control via a Teensy microcontroller. GPIOs press the controller’s buttons, and digipots replace the analog sticks. Software on the Teensy drives the digipots and presses the buttons, interpreting a custom protocol sent over USB from the computer, which also gets some custom software to send the signals.

So if you’re keeping score: a button press on a keyboard is converted to USB, sent to a PC, converted to a custom serial protocol, sent to a Teensy which emulates a human for a controller that then coverts the signals back into the Xbox’s USB protocol. Pshwew!

Along the way, there’s learning at every stage, which is really the point of an exercise like this. And [Agent86] says that it mostly works, with some glitches in the mouse-to-joystick mapping. But if you’re interested in any part of this crazy chain, you’ve now got a model for each of them.

Warbots: Is It Already Too Late?

January 28, 2016 by Al Williams 53 Comments

In 1971, a non-profit formed that holds the World Economic Forum each year. The Forum claims it “Engages the foremost political, business and other leaders of society to shape global, regional and industry agendas.” This year, the Forum hosted a session: What If: Robots Go To War? Participants included a computer science professor, an electrical engineering professor, the chairman of BAE, a senior fellow at the Vienna Center for Disarmament and Non-Proliferation, and a Time magazine editor.

Continue reading “Warbots: Is It Already Too Late?” →

Old School Gauges Let You Know Which Way The Wind Blows

January 27, 2016 by Dan Maloney 14 Comments

When your passion is a sport that depends on Mother Nature’s cooperation, you need to keep a close eye on weather conditions. With this in mind, and not one to let work distract him from an opportunity to play, [mechanicalsquid] decided to build a wind-monitoring gauge with an old-school look to let him know when the wind is right for kitesurfing.

Being an aficionado of big engineering helped [mechanicalsquid] come up with a style for his gauge – big old dials and meters. We hesitate to apply the “steampunk” label to every project that retasks old technology, but it sure looks like a couple of the gauges he used could have been for steam, so the moniker probably fits here. Weather data for favorite kitesurfing and windsurfing locales is scraped from the web and applied to the gauges to indicates wind speed and direction. [mechanicalsquid] made a valiant effort to drive the voltmeter coil directly from the Raspberry Pi, but it was not to be. Servos proved inaccurate, so steppers do the job of moving the needles on both gauges. Check out the nicely detailed build log for this one, too.

For more weather station fun be sure to check out this meter-based weather station with a slightly more modern look. And for another build in the steampunk style, this vintage meter and Nixie power display is sure to impress.

Conductive Concrete Melts Snow And Ice

January 27, 2016 by James Hobson 93 Comments

Winter sucks. Ice sucks. Shoveling sucks. What if roads, or your driveway, could get rid of snow and ice by themselves? (…with the help of our friend, the electron.)

A few days ago we shared a project about building an epic snow-melting system right into your driveway. But for obvious reasons, it’s not that easy to do — or cheap. But [Chris Tuan], an engineering professor at the University of Nebraska thinks he can change that.

He’s created his own special formula for conductive concrete. Which means you can turn the concrete into a resistive heat load. And this isn’t just a university research project that is going nowhere; it’s actually being trialed by the FAA for use in airports . There is a patch of it in Omaha undergoing testing right now.

And it’s actually not that complex. It consists of a mixture of 20% steel shavings and carbon particles, in a regular run-of-the-mill concrete. Apparently, this is enough to cause the entire patch of concrete to become conductive, meaning if you pump enough juice through it — it’d definitely melt some ice on top.

[Thanks Michael!]