You Speak, Your Scope Obeys

March 29, 2016 by Elliot Williams 17 Comments

We’ve been scratching our heads about the various voice-recognition solutions out there. What would you really want to use one for? Turning off the lights in your bedroom without getting up? Sure, it has some 2001: A Space Odyssey ~~flare~~ flair, but frankly we’ve already got a remote control for that. The best justification for voice control, in our mind, is controlling something while your hands or eyes are already busy.

[Patrick Sébastien Coulombe] clearly has both of his hands on his oscilloscope probes. That’s why he developed Speech2SCPI, a quick mash-up of voice recognition and an oscilloscope control protocol. It combines the Julius open-source speech recognizer project with the Standard Commands for Programmable Instruments (SCPI) syntax to make his scope obey his every command. You’ve got to watch the video below the break to believe how well it works. It even handles his French accent.

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Dirt-Cheap USB Arduino Hack From The Past

March 29, 2016 by Elliot Williams 17 Comments

Mass production is a wonderful thing. Prices fall, and hobby hackers get cheap gear. The mind then wanders towards what can be done with it. So it’s little wonder that someone like [Aaron Christophel] would try to repurpose those sub-$3 AVR programmers that are all over eBay (translated poorly out of German here, but demonstrated in the video embedded below).

[Aaron] didn’t have to do much, really. The only trick is that you’ll first need to re-flash the existing ISP firmware with one that lets you upload code to the device itself over USB. If you don’t have an Arduino on hand to re-flash, buy at least two of the cheap programmers — one to program the other ones. Once you’ve done that, you have essentially an Arduino with limited pinout and two onboard LEDs, but in a nice small form-factor and with built-in USB. [Aaron] even provides an Arduino boards.txt file to make it all work smoothly within the IDE.

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Lighting Fires With Lemons

March 26, 2016 by Elliot Williams 64 Comments

We all know that you can stick copper and zinc in an acid and make a battery. And the classic demonstration of this is with a lemon. YouTuber [NorthSurvival] takes this to an extreme — starting a fire by shorting his lemon battery across some steel wool. (Video embedded below.)

Now calling this a “survival tip” is pushing it. A lot. When’s the last time you went camping with a bunch of zinc and copper nails, much less a supply of fresh lemons? It might be easier to put some matches in a waterproof canister, or just bring a lighter. But when the zombie apocalypse comes, and all the lighters are used up, the man with a lemon tree will be a millionaire.

Seriously, though, this demo made us question a few assumptions. First, when people do the potato- or lemon-battery experiment, they often use multiple lemons. Why? Hooking the pins up like [NorthSurvival] did in series seems like a no-brainer after the fact.

And the lemon seems to be putting out a fair amount of juice (Amperes, that is). We’ve got to wonder — what is the short-circuit current of a lemon battery? And why haven’t we seen specs anywhere? What kind of “science education” experiment is this anyway, without measurements?

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Michael Ossmann Makes You An RF Design Hero

March 23, 2016 by Elliot Williams 45 Comments

To a lot of people, radio-frequency (RF) design is black magic. Even if you’ve built a number of RF projects, and worked your way through the low-lying gotchas, you’ve probably still got a healthy respect for the gremlins lying in wait around every dimly-lit corner. Well, [Michael Ossmann] gave a super workshop at the Hackaday Superconference to give you a guided tour of the better-illuminated spaces in RF design.

[Michael] is a hacker-designer, and his insights into RF circuit design are hard-won, by making stuff. The HackRF One is probably his most famous (and complex) project, but he’s also designed and built a number of simpler RF devices. And the main point of his talk is that there’s a large range of interesting projects that are possible without getting yourself into the fringes of RF design (which require expensive test equipment, serious modelling, or a Ph.D. in electro-wavey-things).

You should watch [Mike]’s workshop which is embedded below. That said, here’s the spoilers. [Mike] suggests five rules that’ll keep your RF design on the green, rather than off in the rough.

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Embed With Elliot: ARM Makefile Madness

March 22, 2016 by Elliot Williams 47 Comments

To wrap up my quick tour through the wonderland of make and makefiles, we’re going to look at a pair of possible makefiles for building ARM projects. Although I’m specifically targeting the STM32F407, the chip on a dev board that I have on my desk, it’s reasonably straightforward to extend these to any of the ST ARM chips, and only a bit more work to extend it to any ARM processor.

If you followed along in the first two installments of this series, I demonstrated some basic usages of make that heavily leveraged the built-in rules. Then, we extended these rules to cross-compile for the AVR series of microcontrollers. Now we’re going to tackle a more complicated chip, and that’s going to mean compiling with support libraries. While not required, it’s a lot easier to get an LED blinking on the ARM platforms with some additional help.

One of the main contributions of an IDE like Arduino or mbed or similar is the ease of including external libraries through pull-down menus. If you’ve never built a makefile-based project before, you might be surprised how it’s not particularly more difficult to add libraries to your project.
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Add Fiber-optic Control To Your CNC

March 20, 2016 by Elliot Williams 16 Comments

CNC machines can be very noisy, and we’re not talking about the kind of noise problem that you can solve with earplugs. With all those stepper motors and drivers, potentially running at high-speed, electrical noise can often get to the point where it interferes with your control signals. This is especially true if your controller is separated from the machine by long cable runs.

But electrical noise won’t interfere with light beams! [Musti] and his fellow hackers at IRNAS decided to use commodity TOSLINK cables and transmitter / receiver gear to make a cheap and hackable fiber-optic setup. The basic idea is just to bridge between the controller board and the motor drivers with optical fiber. To make this happen, a couple of signals need to be transmitted: pulse and direction. They’ve set the system up so that it can be chained as well. Serializing the data, Manchester encoding it for transmission, and decoding it on reception is handled by CPLDs for speed and reliability.

The team has been working on this project for a while now. If you’d like some more background you can check out their original design ideas. Design files from this released version are up on GitHub. A proposed improvement is to incorporate bi-directional communications. Bi-directional comms would allow data like limit-switch status to be communicated back from the machine to the controller over fiber.

This optical interface is in service of an open-source plasma cutter design, which is pretty cool in itself. And if the IRNAS group sounds familiar to you, that may be because we recently ran a story on their ambitious gigabit ethernet-over-lightbeam project.

Fuzzy Blanket Hides Serious Tech

March 20, 2016 by Elliot Williams 11 Comments

Who needs the Internet of Things? Not this interactive, sound playback blanket! Instead, hidden within its soft fuzzy exterior, it makes use of a NRF24L01+ module to speak directly with its sound server.

The project was built for a school, and let the students record whatever sounds they think are important into a Raspberry Pi. Then, the students assembled the physical felt blanket, with the sensors sewn inside, and could play back their favorite sounds by clambering all over the floor. It’s a multi-sensory, participatory, DIY extravaganza. We wish we did cool stuff like that in grade school.

What? Your “blankie” doesn’t transmit data to a Pure Data application? Well, [Dan Macnish] is here to help you change that. This well-written entry on Hackady.io describes the setup that he used to make the blanket’s multiple touch sensors send small packets over the air, and provides you with the Pd code to get it all working on GitHub..

We like DIY music controllers a lot, and this simple setup stands to be more useful than just blanket-making. And in this age of everything-over-WiFi, it’s refreshing to see a straight-up 2.4 GHz radio build when that’s all that was necessary.

[Dan]’s complaint that the NRF24 modules could only reach 3m or so strikes us as strange though. Perhaps it’s because of all of the metal in close proximity to the NRF24’s antenna?