Is It A Stepper? Or Is It A Servo?

April 30, 2016 by Elliot Williams 37 Comments

Almost everyone who is involved with 3D printing thinks to themselves at some point, “this could all be done using a closed-loop system and DC motors”. Or at least everyone we know. There’s even one commercial printer out there that uses servo control, but because of this it’s not compatible with the rest of the (stepper-motor driven) DIY ecosystem.

[LoboCNC] wanted to change this, and he’s in a unique position to do so, having previously built up a business selling PIC-based servo controllers. His “servololu” is essentially a microcontroller and DC motor driver, with an input for a quadrature encoder for feedback. The micro takes standard step/direction input like you would use to drive a stepper motor, and then servos the attached DC motor to the right position. It even signals when it has an error.
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Don’t Tempt The Demo Gods

April 30, 2016 by Elliot Williams 9 Comments

Including a live technical demonstration as part of a presentation is a lot like walking a tightrope without a net. Which isn’t to say that we don’t do it — we just keep our fingers crossed and bring our lucky horseshoe. The demo gods have smote [Quinn] a mighty blow, in front of a class at Stanford, no less.

[Quinn]’s scratch-built computer, Veronica, failed to boot in front of a hall of eager students. When the pressure was off, in the comfort of her own lab, [Quinn] got to debugging. You should read her blog post if you’re at all interested in retrocomputing or troubleshooting of low-level hardware bugs. But if you just can’t spare the five minutes for a pleasant read, here’s a spoiler: watch out for flaky card-edge connectors. All’s well that ends well, with a game of pong.

We’ve been following Veronica from her very first clock cycles, so we’re happy to see her back on her feet again. Good job, [Quinn]!

Saving Lives With Open-Source Electrocardiography

April 29, 2016 by Elliot Williams 17 Comments

A few months ago, MobilECG wowed us with a formidable electrocardiograph (ECG, also EKG) machine in the format of a business card, complete with an OLED display. We’ve seen business card hacks before, but that was the coolest. But that’s peanuts compared with the serious project that it supports: making an open-source ECG machine that can actually save lives by being affordable enough to be where it’s needed, when it’s needed.

The project, MobilECG, is an open-source, wearable device that supports all of the major ECG modes. In their talk, [Péter Isza] and [Róbert Csordás] taught us a lot about what that exactly entails and how the heart works. We learned a lot, and we’ll share some of that with you after the break.

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Connect All Your IoT Through Your Pi 3

April 29, 2016 by Elliot Williams 34 Comments

If you’re playing Hackaday Buzzword Bingo, today is your lucky day! Because not only does this article contain “Pi 3” and “IoT”, but we’re just about to type “ESP8266” and “home automation”. Check to see if you haven’t filled a row or something…

Seriously, though. If you’re running a home device network, and like us you’re running it totally insecurely, you might want to firewall that stuff off from the greater Interwebs at least, and probably any computers that you care about as well. The simplest way to do so is to keep your devices on their own WiFi network. That shiny Pi 3 you just bought has WiFi, and doesn’t use so much power that you’d mind leaving it on all the time.

Even if you’re not a Linux networking guru, [Phil Martin]’s tutorial on setting up the Raspberry Pi 3 as a WiFi access point should make it easy for you to use your Pi 3 as the hub of your IoT system’s WiFi. He even shows you how to configure it to forward your IoT network’s packets out to the real world over wired Ethernet, but if you can also use the Pi 3 as your central server, this may not even be necessary. Most of the IoT services that you’d want are available for the Pi.

Those who do want to open up to the world, you can easily set up a very strict firewall on the Pi that won’t interfere with your home’s normal WiFi. Here’s a quick guide to setting up iptables on the Pi, but using even friendlier software like Shorewall should also get the job done.

Still haven’t filled up your bingo card yet? “Arduino!”

Colin Furze Flies The Dangerous Skies

April 28, 2016 by Elliot Williams 111 Comments

To quote our tipster: “Furze is my hero … You just need to know how to weld and have zero consideration for your personal well-being.” We’re not exactly sure that he has no consideration, but [Colin Furze] definitely pulls off some dangerous hacks. This time? Two-engine hoverbike. We don’t have to tell you to watch the video, do we? Continue reading “Colin Furze Flies The Dangerous Skies” →

Robot Beats Piano Tiles

April 28, 2016 by Elliot Williams 21 Comments

Machines running out of control are one of the staples of comedy. For the classic expression, see Chaplin’s “Modern Times”. So while it starts out merely impressive that [Denver Finn]’s robotic fingers can play an iPad piano video game, it ends up actually hilarious. Check out the linked video to see what we mean.

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Threadless Ballscrew For 3D Printer

April 28, 2016 by Elliot Williams 53 Comments

[2n2r5] posted up a mechanism that we’d never seen before — a threadless ballscrew that turns rotational into linear motion with no backlash. It works by pressing the edge of three bearings fairly hard up against a smooth rod, at an angle. The bearings actually squeeze the rod a little bit, making a temporary indentation in the surface that works just like a screw thread would. As the bearings roll on, the rod bounces back to its original shape. Watch it in action in the video below.

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