Open Source Robotics With WireBeings

April 13, 2016 by 9 Comments

Everyone needs a cute robotic buddy, right? [Matthew Hallberg] created WireBeings, an open source 3D printed robotic platform. Looking like a cross between Wall-E and Danbo, WireBeings is designed around the Arduino platform. We do mean the entire platform. You can fit anything from an Arduino micro to a Mega2560 stacked with 3 shields in its oversized head. There’s plenty of room for breadboards and custom circuits.

WireBeings is designed to be 3D printed. All the non-printable parts are commonly available. Gear motors, wheels, the ubiquitous HC-SR04 ultrasonic sensor, and a few other parts are all that is needed to bring this robot to life. Sketches are downloaded via USB. Once running, WireBeings can communicate via an HC-06 Bluetooth module.  If the Arduino isn’t enough power for whatever project you’re working on, no problem. [Matt] designed WireBeings to carry a smartphone. Just connect the robot and phone via Bluetooth, and let the phone’s processor do all the heavy lifting. What if you don’t have a spare phone? Check our report on hacks using prepaid Android Smartphones.

We could see WireBeings as the centerpiece for a “learn Arduino” class at a hackerspace. Start with the classic blinky sketch on one of the robot’s eyes. Build from there until the students have a fully functioning robot.

There is definitely room for improvement on the WireBeings project. [Matt] made the rookie mistake of going with a single 9-volt battery to power his creation. While a 9V is fine for the Arduino, those motors will quickly drain it. [Matt’s] planning on moving to a LiPo in the future. Why not stop by the project page and give him a hand?

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Bela: Real-Time BeagleBone Audio/Analog Cape

April 13, 2016 by 16 Comments

Bela is a cape for the BeagleBone Black that’s aimed at artists and musicians. Actually, the cape is much less than half of the story — the rest is in some clever software and a real-time Linux distribution. But we’re getting ahead of ourselves. Let’s talk hardware first.

First off, the cape has stereo input and output as well as two amplified speaker outs. It can do all of your audio stuff. It also has two banks of analogue inputs and outputs, each capable of handling eight signals. In our opinion, this is where the Bela is cool. In particular, the analog outputs are not Arduino-style “analog outputs” where it’s actually a digital output on which you can do PWM to fake an analog signal. These are eight 16-bit outputs from an AD5668 DAC which means that you can use the voltages directly, without filtering.

Then there’s the real trick. All of these input and output peripherals are hooked up to the BeagleBone’s Programmable Realtime Units (PRUs) — a hardware subsystem that’s independent of the CPU but can work along with it. The PRU is interfaced with the real-time Linux core to give you sub-microsecond response in your application. This is a big deal because a lot of other audio-processing systems have latencies that get into the tens of milliseconds or worse, where it starts to be perceptible as a slight lag by humans.

The downside of this custom analog and audio I/O is that it’s not yet supported by kernel drivers, and you’ll need to use their “Heavy Audio Tools” which compiles Pd programs into C code, which can then drive the PRUs. Of course, you can write directly for the PRUs yourself as well. If you just want to play MP3s, get something you have a bunch of simpler, better options. If you need to do responsive real-time audio installations, Bela is a way to go.

The project is open-source, but we had to do a bunch of digging to find what we were looking for. The hardware is in zip files here, and you’ll find the software here. The demo projects look/sound pretty cool and their Kickstarter is long over-funded, so we’re interested to see what folks make with these.

A Developer’s Kit For Medical Ultrasound

April 12, 2016 by 23 Comments

From watching a heart valve in operation to meeting your baby before she’s born, ultrasound is one of the most valuable and least invasive imaging tools of modern medicine. You pay for the value, of course, with ultrasound machines that cost upwards of $100k, and this can put them out of reach in many developing countries. Sounds like a problem for hackers to solve, and to help that happen, this 2016 Hackaday prize entry aims to create a development kit to enable low-cost medical ultrasounds.

PhysicalSpaceDeveloped as an off-shoot from the open-source echOpen project, [kelu124]’s Murgen project aims to enable hackers to create an ultrasound stethoscope in the $500 price range. A look at the test bench reveals that not much specialized equipment is needed. Other than the Murgen development board itself, everything on the test bench is standard issue stuff. Even the test target, an ultrasound image of which leads off this article, is pretty common stuff – a condom filled with tapioca and agar. The Murgen board itself is a cape for a BeagleBone Black, and full schematics and code are available.

We’ll be paying close attention to what comes out of the ultrasound dev kit. Perhaps something as cool as this augmented reality ultrasound scope?

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Professional CNC Vacuum Table Holds Workpieces With Ease

April 12, 2016 by 21 Comments

If you do a lot of one-off parts on your CNC machine you’ll know setup is the worst part of the process. Usually you’re using scrap material, you have to figure out how you’re going to clamp it, make sure the the piece is big enough to use, etc etc. Wouldn’t it be nice to just throw the material on the bed and start machining? Well, with a vacuum table as nice as this, you pretty much can!

[Jack Black] has an awesome CNC machine. As he’s been expanding his prototyping abilities, he decided he needed a better way of securing work pieces for machining, so he machined a two-piece aluminum vacuum table.
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E-paper Tide Clock Easy To Mistake For Art Print On The Wall

April 12, 2016 by 23 Comments

[Stephen B.] kickstarted a MicroPython board. When he got it, he was pleasantly surprised to find that it worked great. His jaded soul balmed with a good experience, he found himself armed with a tool in search of a project. Then he remembered something that had stuck with him, which was a tide clock.

He lives 70 miles from the sea, but his stepmother had a birthday coming up. She went swimming daily, so he had his excuse to build. Unlike his inspiration project, a bunch of seven segment LEDs would not be received well by a technically disinclined stepmother with a well decorated home. So, instead of those, he went with an epaper display. It looks great.

He wanted to use the Kindle display to save money, but the weird power levels needed scared him off. He spent a bit more on a module, but it was probably worth it in time savings. Micropython board, an RTC, a battery, and e-paper display in hand, he had everything needed to build the clock but aesthetics.

Luckily a local frame shop entertained him by letting him pick up frames until he could find one that fit. He put a nice shoreline print together, installed the devices into the frame, and ended up with a really good looking clock. Sure it only tells time four times a day, but that’s enough if you live a life by the sea.

Rotating Plasma Vortex Speaker

April 12, 2016 by 27 Comments

[Anthony Garofalo] has made a fancier plasma speaker. Not content with a simple spark, he uses a plasma vortex. To make the vortex, the spark gap is swapped out for an electrode placed in the centre of a ring magnet. The Lorentz force experienced by the arc causes it to rotate rapidly enough round the arc of the magnet’s centre to appear as a continuous sheet of plasma.

The speaker gets its power from an inverter using a flyback transformer driven through a MOSFET by a 555-based pulse width modulator. You can see the result in the video below the break, it’s very impressive to look at but probably not quite ready to sit in your hi-fi stack. The resulting sound isn’t quite as good as that from a stationary arc, but it looks a lot cooler.

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Stealing 3D Prints By Sound

April 12, 2016 by 48 Comments

In the open hardware world, we like to share 3D design files so that our friends and (global) neighbors can use and improve them. But we’ve all printed things from time to time that we’d like to keep secret. At least this is the premise behind this article in Science which proposes a novel method of 3D-printer-based industrial espionage: by recording the sound of the stepper motors and re-creating the toolpath.

Unfortunately, the article is behind a paywall so we’re short on the details, but everyone who’s played the Imperial March on their steppers has probably got the basic outline in their mind. Detecting the audio peak corresponding to a step pulse should be fairly easy. Disentangling the motions of two axes would be a bit harder, but presumably can be done based on different room-acoustic filtering of the two motors. Direction is the biggest question mark for us, but a stepper probably has a slightly audible glitch when reversing. Keeping track of these reversals could do the trick.

What do you think? Anyone know how they did it? Does someone with access to the full article want to write us up a summary in the comments?

[Thanks LVfire via Ars Technica]

[Edit: We were sent a copy of the full article (thanks [PersonUnknown]!) and it doesn’t explain any technical details at all. Save yourself the effort, and have fun speculating, because reading the article won’t help.]