How Accurate Is Microstepping Really?

August 29, 2016 by 160 Comments

Stepper motors divide a full rotation into hundreds of discrete steps, which makes them ideal to precisely control movements, be it in cars, robots, 3D printers or CNC machines. Most stepper motors you’ll encounter in DIY projects, 3D printers, and small CNC machines are bi-polar, 2-phase hybrid stepper motors, either with 200 or — in the high-res variant — with 400 steps per revolution. This results in a step angle of 1.8 °, respectively 0.9 °.

Can you increase the resolution of this stepper motor?

In a way, steps are the pixels of motion, and oftentimes, the given, physical resolution isn’t enough. Hard-switching a stepper motor’s coils in full-step mode (wave-drive) causes the motor to jump from one step position to the next, resulting in overshoot, torque ripple, and vibrations. Also, we want to increase the resolution of a stepper motor for more accurate positioning. Modern stepper motor drivers feature microstepping, a driving technique that squeezes arbitrary numbers of microsteps into every single full-step of a stepper motor, which noticeably reduces vibrations and (supposedly) increases the stepper motor’s resolution and accuracy.

On the one hand, microsteps are really steps that a stepper motor can physically execute, even under load. On the other hand, they usually don’t add to the stepper motor’s positioning accuracy. Microstepping is bound to cause confusion. This article is dedicated to clearing that up a bit and — since it’s a very driver dependent matter — I’ll also compare the microstepping capabilities of the commonly used A4988, DRV8825 and TB6560AHQ motor drivers.

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Hackaday Prize: 20 Projects That Are The Height Of Automation

August 29, 2016 by 7 Comments

Automation makes the world go around. Whether it’s replacing elevator attendants with buttons, replacing songwriters with computer algorithms, or giving rovers on Mars the same sense and avoid capability as a Tesla, Automation makes our lives easier and better. Today we’re excited to announce the twenty projects that best demonstrate the possibilities of Automation in the running for the 2016 Hackaday Prize. These projects tackled problems ranging from improving the common stepper motor to flying Lidar around a neighborhood on a gigantic ducted fan.

The winners of the Hackaday Prize automation challenge are, in no particular order:

If your project is on the list, congrats. You just won $1000 for your hardware project, and are now moving up to the Hackaday Prize finals where you’ll have a chance to win $150,000 and a residency at the Supplyframe DesignLab in Pasadena.

Assistive TechnologiesIf your project didn’t make the cut, there’s still an oppurtunity for you to build the next great piece of hardware for The Hackaday Prize. The Assistive Technologies Challenge is currently under way challenging you to build a project that helps others move better, see better, or live better.

We’re looking for exoskeletons, a real-life Iron Man, a better wheelchair, a digital braille display, or the best educational software you can imagine.

Like the Design Your Concept, Anything Goes, Citizen Science, and Automation rounds of the the Hackaday Prize, the top twenty projects will each win $1000 and move on to the Hackaday Prize finals for a chance to win $150,000 and a residency at the Supplyframe DesignLab in Pasadena

If you don’t have a project up on Hackaday.io, you can start one right now and submit it to the Hackaday Prize. If you’re already working on the next great idea in assistive technologies, add it to the Assistive Technologies challenge using the dropdown menu on the sidebar of your project page.

The Hackaday Prize is the greatest hardware competition on Earth. We want to see the next great Open Hardware project benefit everyone. We’re working toward that by recognizing people who build, make, and design the coolest and most useful devices around.

The HackadayPrize2016 is Sponsored by:

Building Better Tube Amps With Heathkit Parts

August 29, 2016 by 14 Comments

[Justin] had been trying to find a good tube amp for years, but all the best examples were either expensive or a complete basket case. Instead of buying a vintage stereo tube amp, he decided to build his own using the guts of a Heathkit AA-100, a popular tube amp from the 60s and 70s that doesn’t have a great reputation for sound quality.

This project was based on an earlier project from a decade ago that replicated the very popular Dynaco ST-70 tube amp from parts taken from the Heathkit AA-100. The schematic for this conversion was readily available on the usual tube head message boards, and a few PCBs were available for the input stage.

With the schematic in hand, the next thing for [Justin] to do was get a nice enclosure. High quality tube amps are valued as much for their appearance as they are for their sound quality, and after giving his father-in-law a few sketches, a cherry hardwood chassis stained in a beautiful golden brown appeared on [Justin]’s workbench.

The big iron for this new tube amp was taken directly from the old Heathkit, and a few hours in front of a mill netted [Justin] a chassis panel drilled out for the transformers and tube sockets. The rest of the project was a bit of assembly, point-to-point wiring, and wire management giving [Justin] a fantastic amplifier that will last for another fifty years until someone decides to reuse the transformers.

Hyperuniformity — A Hidden Order Found In The Greatest Set Of Eyes

August 29, 2016 by 62 Comments

Of all the things evolution has stumbled across, the eye is one of the most remarkable. Acting as sort of a ‘biological electromagnetic transducer’, the eye converts incoming photons into electrical and chemical spikes, known as action potentials. These spikes then drive the brain of the host life form. Billions of years of natural selection has produced several types of eyes, with some better than others. It would be an honest mistake to think that the human eye is at the top of the food chain, as this is not the case. Mammals underwent a long stint scurrying around in dark caves and crevasses, causing our eyes to take a back seat to other more important functions, such as the development of a cortex.

There are color sensitive cones in all eyes. Mammals have three types of cones, which are…wait for it…Red, Blue and Green. Our red and green cones are relatively recent on the evolutionary timescale – appearing about 30 million years ago.

The way these cones are distributed around our eyes is not perfect. They’re scattered around in lumpy, uneven patterns, and thus give us an uneven light sampling of our world. Evolution simply has not had enough time to optimize our eyes.

There is another animal on this planet, however, that never went through “the dark ages” as mammals did. This animal has been soaring high above its predators for over 60 million years, allowing its eyes to reach the pinnacle of the natural selection process. A bald eagle can spot a mouse from over a mile away. Birds eyes have 5 types of light sensitive cones – red, blue and green like our own. But add in violet and a type of cone that can detect no light, or black. But it is the way these cones are distributed around the bird’s eye that is most fascinating, and the subject of today’s article.

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Let’s Put A Hackerspace In Prison

August 29, 2016 by 26 Comments

The Hack42 Hackerspace in Arnhem, Netherlands is one of the best hackerspaces we’ve ever seen. After taking over a decommissioned military base, the Hack42 crew has filled a compound rimmed with razor wire with eclectic gizmos, tools, and a community that keeps growing the space. At this year’s EMF camp, Hack42 member [jos] laid out his plan to found the ultimate Hackerspace. He’s going to put a hackerspace in prison to create the ultimate hacker village, a monument to technomancy, and an anti-panopticon panopticon.

[jos] recently noticed a very large, very old prison — currently used to house refugees — went up for sale. This prison, located in downtown Arnhem, Netherlands is a panopticon, a concept for prisons popularized in the 1800s, with most designs based on a circular structure with prison cells along the diameter around the circumference and a guard house in the center. This gigantic building is 55 meters (180 feet) in diameter, and 46 meters (150 feet) tall at its highest point. This gigantic prison dome could contain the White House inside its walls, a few blue whales, and could almost fit a space shuttle stack under the dome (the orbiter itself would fit just fine if there were a door).

The ambitious vision for this prison-come-hackerspace is a permanent venue not unlike other hackercamps where hackers can stay for weeks or months to build a project, a venue for like-minded people to meet up, and a place for students to do graduation projects under the wings of academic leadership. A community is one thing, but this former prison would also be the largest hackerspace by enclosed volume, opening it up to some very cool, very large builds. Inter-office quadcopter mail was mentioned in the talk.

[jos] is looking for comments, ideas, and remarks via this Google form to, “convince the money-people to fork over the funds.” If you’ve ever wanted to contribute to something big, this is your chance.

Raspberry Pi Hive Mind

August 29, 2016 by 34 Comments

Setting up a cluster of computers used to be a high-end trick used in big data centers and labs. After all, buying a bunch of, say, VAX computers runs into money pretty quickly (not even counting the operating expense). Today, though, most of us have a slew of Raspberry Pi computers.

Because the Pi runs Linux (or, at least, can run Linux), there are a wealth of tools out there for doing just about anything. The trick is figuring out how to install it. Clustering several Linux boxes isn’t necessarily difficult, but it does take a lot of work unless you use a special tool. One of those tools is Docker, particularly Docker Swarm Mode. [Alex Ellis] has a good video (see below) showing the details of a 28 CPU cluster.

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Hackaday Prize Entry: Automated Hydroponics

August 28, 2016 by 25 Comments

This team project for the Hackaday Prize is a solution to a rather important problem. Imagine growing plants for use as biomarkers for pollution. It’s a great idea, but how do you grow the plants in the first place? This team is building a space-saving hydroponic system that packs the most green into the least amount of space. It’s simple, and can be built almost entirely with parts from the local home supply store.

The design of this hydroponic system is based on a few PVC pipes, arranged vertically, joined together with a few 90 degree bends. In each course of pipe, a few holes are drilled to accept a plastic cup. This cup is filled with some sort of growing medium, and the Genuino-based controller takes care of everything else. Watering the plants, turning the lights on and off, and recording the nutrient concentration of the water is all possible with a simple microcontroller.

Right now the team has a huge stack of perforated PVC pipe and a Genuino-based brain box that takes care of everything plants need. It’s going to take a bit of time for the plants to grow, but this is still one of the most compact hydroponic systems we’ve seen.

You can check out a video of the entire setup below.

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