Putting Wind In VR By Watching The Audio Signal

December 14, 2017 by Donald Papp 11 Comments

A simple way to integrate physical feedback into a virtual experience is to use a fan to blow air at the user. This idea has been done before, and the fans are usually the easy part. [Paige Pruitt] and [Sean Spielberg] put a twist on things in their (now-canceled) Kickstarter campaign called ZephVR, which featured two small fans mounted onto a VR headset. The bulk of their work was in the software, which watches the audio signal for recognizable “wind” sounds, and uses those to turn on one or both fans in response.

The benefit of using software to trigger fans based on audio cues is that the whole system works independently of everything else, with no need for developers and software to build in support for your project, or to use other middleware. Unfortunately the downside is that the results are only as good as the ability of software to pick the right sounds and act on them. Embedded below is a short video showing a test in action.

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Robotic Arms Controlled By Your….. Feet?

June 7, 2017 by James Hobson 12 Comments

The days of the third hand’s dominance of workshops the world over is soon coming to an end. For those moments when only a third hand is not enough, a fourth is there to save the day.

Dubbed MetaLimbs and developed by a team from the [Inami Hiyama Laboratory] at the University of Tokyo and the [Graduate School of Media Design] at Keio University, the device is designed to be worn while sitting — strapped to your back like a knapsack — but use while standing stationary is possible, if perhaps a little un-intuitive. Basic motion is controlled by the position of the leg — specifically, sensors attached to the foot and knee — and flexing one’s toes actuates the robotic hand’s fingers. There’s even some haptic feedback built-in to assist anyone who isn’t used to using their legs as arms.

The team touts the option of customizeable hands, though a soldering iron attachment may not be as precise as needed at this stage. Still, it would be nice to be able to chug your coffee without interrupting your work.

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Recapture Radio’s Roots With An Updated Regenerative Receiver

January 19, 2017 by Dan Maloney 12 Comments

Crystal radios used to be the “gateway drug” into hobby electronics. Trouble was, there’s only so much one can hope to accomplish with a wire-wrapped oatmeal carton, a safety-pin, and a razor blade. Adding a few components and exploring the regenerative circuit can prove to be a little more engaging, and that’s where this simple breadboard regen radio comes in.

Sometimes it’s the simple concepts that can capture the imagination, and revisiting the classics is a great way to do it. Basically a reiteration of [Armstrong]’s original 1912 regenerative design, [VonAcht] uses silicon where glass was used, but the principle is the same. A little of the amplified RF signal is fed back into the tuned circuit through an additional coil on the ferrite rod that acts as the receiver’s antenna. Positive feedback amplifies the RF even more, a germanium diode envelope detector demodulates the signal, and the audio is passed to a simple op amp stage for driving a headphone.

Amenable to solderless breadboarding, or even literal breadboard construction using dead bug or Manhattan wiring, the circuit invites experimentation and looks like fun to fiddle with. And getting a handle on analog and RF concepts is always a treat.

[via r/electronics]

Derek Schulte: Path Planning For 3D Printers

January 3, 2017 by Elliot Williams 54 Comments

[Derek Schulte] designed and sells a consumer 3D printer, and that gives him a lot of insight into what makes them tick. His printer, the New Matter MOD-t, is different from the 3D printer that you’re using now in a few different ways. Most interestingly, it uses closed-loop feedback and DC motors instead of steppers, and it uses a fairly beefy 32-bit ARM processor instead of the glorified Arduino Uno that’s running many printers out there.

The first of these choices meant that [Derek] had to write his own motor control and path planning software, and the second means that he has the processing to back it up. In his talk, he goes into real detail about how they ended up with the path planning system they did, and exactly how it works. If you’ve ever thought hard about how a physical printhead, with momentum, makes the infinitely sharp corners that it’s being told to in the G-code, this talk is for you. (Spoiler: it doesn’t break the laws of physics, and navigating through the curve involves math.)

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A Buck-Boost Converter From The Ground Up

November 22, 2016 by Dan Maloney 17 Comments

DC to DC conversion has come a long way. What was once took an electromechanical vibrator and transformer has been reduced to a PC board the size of a largish postage stamp that can be had for a couple of bucks on eBay. So why roll your own buck-boost converter for the ground up? Maybe because sometimes the best way to learn is by doing.

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Building A Ball-Balancing Robot

October 24, 2013 by Marsh 16 Comments

robotBallBalance

If you want a different kind of feedback systems challenge, ditch the Segway-style robots and build one that can balance on a ball. UFactory is a startup in Shenzhen, and this impressive little guy is a way of showing their skills applied to the classic inverted pendulum. At nearly 18 inches tall and weighing just over six pounds, the robot boasts a number of features beyond an accelerometer and gyroscope: it has both a WiFi module and a camera, and can be controlled via a homemade remote control or a Kinect.

The build uses plastic omni-directional wheels attached to 3 brushed dc motors, which attach to the base of the robot with custom-made aluminum brackets. The UFactory gang constructed the robot’s body out of three acrylic discs, which hold the electronics directly above the wheels. The brain seems to be an STM32 microcontroller that connects up to the motors and to the sensors.

You won’t find the code on their Instructable yet, but according to the comments they have plans to make the entire project open source. If you’re desperate for more details, the UFactory team seems willing to provide source code and other information via email. Make sure you see the video after the break, particularly the end where they demonstrate interference and carrying loads. This isn’t the first ball pendulum we’ve seen; take a trip down memory lane with the BallP ball balancing robot from 2010.

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Causing Trouble At RedBull Creation 2013

June 17, 2013 by Caleb Kraft 26 Comments

Skullduggery systems (a first time participant) came up with an extremely ambitious idea for their instrument. It was to be a jug, that would have a changing pitch based on water being pumped in and out. Ultimately, they ran into a few issues that meant that the effect wasn’t quite what they were looking for. They shouldn’t feel too bad, a bunch of teams didn’t succeed in making things the first year they participated.

What their instrument did do, however, I found simply delightful. The jug sounded just like feedback from the sound system. The contest was happening during a big music festival called the NorthSide festival. There was a stage and a huge crowd most of the time. They were testing their jug and we noticed that the band on stage (with a full crowd at the time), had stopped playing and was checking all their equipment. The sound guys were running around like crazy. They thought they were getting feedback.

We held off for a while and decided we would wait till sound checks to mess with them. While we wanted to cause trouble, we didn’t want to ruin the show for an entire crowd. As you can see in the video, the sound is very much like feedback. They would begin to play, then stop to track down this mysterious feedback. We even tricked [Tyler] the announcer that was talking over our local sound system in the Redbull tent (by accident, I assure you).