Observe The Banana

Like most people who have taken basic science classes or played with refrigerator magnets and paper clips, I knew that stacking up magnets can increase their magnetic pull. Three fridge magnets stuck to each other can hold a longer chain of paper clips than one. Until recently I did not know that their is actually a special way to arrange magnets to increase their lifting power much more. Invented by the late Klaus Halbach, a physicist at Lawrence Livermore National Laboratory in the 1980s (relatively recently in my world view of engineering advancements) the Halbach Array is just such an arrangement. It was invented to focus accelerator particle beams but is now finding many other applications in brushless motors, linear motors and are critical component in a new generation of maglev trains.

This is how the magnets are arranged in a Halbach array:

It does not matter which way N or S is and long as you are consistent to the diagram.  It is not not intuitive (to me anyway) but it turns out that this arrangement combines the magnetic flux along one side for a much greater force, while nearly canceling the pull on the other side.

“The diagram (below) shows the field from a strip of ferromagnetic material with alternating magnetization in the y direction (top left) and in the x direction (top right). Note that the field above the plane is in the same direction for both structures, but the field below the plane is in opposite directions. The effect of superimposing both of these structures is shown in the figure at the bottom:” ^Wikipedia

Here is another nice diagram that shows how the arrangement combines the flux of the different magnets.

The above diagram is from an excellent article entitled Build a Halbach Array which details the construction of a simple Halbach array using a wooden bock and Neodymium-Iron-Boron cube magnets. They point out how hard it is to push the magnets into position as they will always want to flip over and align N to S poles, hence the need for the wooden block and glue.

Halbach arrays can also be constructed in several cylindrical forms which turns out to be very useful for brushless AC motors, magnetic couplings and magnetic bearings.

You can learn more at Halbach Array which includes the customary Wikipedia complement of images, diagrams, formulas and links.

There is also a nice set of links at Halbach Array links

Now you know…..

Photo by Pro-Zak

I have always thought tugboats (or water tractors as they are sometimes called) were pretty cool. Maybe it was the Little Toot book I enjoyed back when I was just a little toot myself, or maybe it is all that raw power packed into a small no frills work machine, like a locomotive for the water. Indeed, I read that some tug boat engines were originally designed for locomotives, then had a sump oil pan added to handle the rolling sea. I have recently learned that many tug boats do not use a conventional propeller (or “screw” for you nautical types) for propulsion, but instead use a fascinating system called a Voith Schneider Propeller (VSP) which combines propulsion and steering in a single efficient unit. Developed nearly 78 years ago, the Voith Schneider unit uses vertical blades protruding from the ships hull from a rotating disc. The blades all travel around a common center axis, while each blade can also rotate on its own center axis. The pitch of the blades is continuously varied as they rotate around the circle so that they push against the water in one direction, while slicing though it in the other. This allows the system to produce thrust in any direction, or produce a rotational thrust around the center of the unit. This system allows a tug boat to move in any direction regardless of which way it is facing, and allows it to rotate in place, giving them excellent maneuverability in tight spaces. Keep reading for more details, diagrams, links, videos and more.

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Earlier today I ran across a fun little video about a new animatronic WALL E robot that will soon be roaming Disney Parks. I kind of like WALL E, although those big round eyes are a bit too Disney cute. Since I have not seen the movie yet, only some fun trailers, I don’t know if he will earn a place in my heart, but he got me thinking about some of the other robots, both real and imagined, that seem to have touched me on an emotional level. So, even though there are already so many robot lists on the net, after the jump is my own Top 5 Favorite Robots

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Hmmmm so many good choices, which one should I choose?

I like sailboats, I like robots, so naturally I was pleased to find this story about sailing robots. The Times of London reports that seven robotic sailing craft will race across the Atlantic Ocean in October 2008. One of them, ‘Pinta the robot sailing boat,’ has been designed at Aberystwyth University, Wales, UK. Pinta is expected to sail for three months at a maximum speed of four knots (about 4.6 mph or 7.4 kilometers per hour). Its designers hope the Pinta will become the first robot to cross an ocean using only wind power. Here is a quote from Mark Neal, Lecturer in the Department of Computer Science at Aberystwyth University.

“This is the first time anybody has attempted to sail across any ocean with an automated boat. The big issue in robotics at the moment is longevity and flexibility in a complicated environment. Something that can survive for two to three months completely unassisted while doing something interesting is a major challenge. If it does get there I will be seriously cheerful. It will open up all the oceans to environmental monitoring by robots.”

This is a cool thing. Giving it some thought, it seems like it could be really tricky managing conventional fabric sails automatically, so many ways to lines to tangle or get caught in unpredictable ways. I guess it is not surprising then to see the robot boat in this picture appears to be using a vertical wing type of sail. The real question is, will they program them to talk like pirates? “Avast ye scurvey dogs, that does not compute!” or maybe “Arrrr mateys, me hard drive be full!”

Over at Roland Piquepaille’s Technology Trends he has more details and lots of good links.

Roland Piquepaille’s Technology Trends via Slashdot

I know people have been hacking together small video transmitter systems into RC planes for years now, but here is a prepackaged system that puts together all the parts and pieces you need into one nice bundle. It has a small color camera with integrated transmitter, video receiver and video goggles with light blocking screen around the edge. At $549 it is not cheap, but could be loads of fun, especially if you fly over any dramatic scenery. Seems like a good thing for a RC club or group to buy and share. One of the most excited parts is the soon to be available options for a OSD (On Screen Display) module which adds things like  altitude, heading, speed and direction to home to your display. An even fancier “DragonOSD” will add a scrolling compass and autopilot functions. There will even be a pan/tilt unit available which will allow you to look around in different directions. That should provide a much greater flying experience by allowing you to look out the side to keep the horizon in view during high banking turns.

Heck, one of these would even be fun on RC cars and boats too!

Follow the link through to the Hobby Lobby product page for a fun video demonstration.

Pilot View FPV 2400 First Person Video from Hobby Lobby

Once they get that robot orchestra made, it looks like they will have someone to conduct. Asimo, that cute little guy from Honda, will be guest conducting the Detroit Symphony Orchestra in a performance of “Impossible Dream.” Along with renowned cellist Yo-Yo Ma, Asimo will open a special concert performance for young people in Detroit on May 13.

From DeviceGuru

May 14 Update

Apparantly the performance went well. Here is a video




TechE Blog has a nice feature on robots what can skillfully play a musical instrument. I like the way the trumpet player and violin player move and sway to the music they are playing in a very life-like way. The percussion player is very cool in the way it improvises along with a human drummer. I am also impressed with the quality of music they produce as playing a musical instrument requires some subtle control. I wonder how the trumpet player changes its “mouth” to produce different notes from one valve position. I imagine iit won’t be long before we see a entire band or even orchestra made up entirely of robots.

TechEBlog » Feature: Robots That Can Skillfully Play a Musical Instrument

We are very avid users of our local library. We go to the library at least once a week, frequently twice or more. We get loads of children’s books for our son the super reader, and adult fiction and non fiction, and sometimes videos (although less now that we Netflix). We love the easy interlibrary loan system available to us and are always requesting things from other libraries in the system. We often have 20-30 items out at one time with 3 or 4 different due dates. With all this going on it would be impossible to keep track of when things were due without the help of the wonderful free service “Library Elf“. This service checks our library account online daily and sends us email notifying us of when books are due the following day, or when interlibrary requests have arrived. You can configure how early it alerts you, or how often it emails. They have almost every major library system available, or (as in our case) they will be happy to add your local library system if it is a Polaris PowerPac (v3.2 or later) or a Dynix library system. Check them out!

From www.libraryelf.com:

Track your library books

Let Elf help you manage your library loans and holds

Avoid overdues with email alerts Check multiple library cards Track books, DVDs, CDs, videos, etc. Join for free

Who uses Elf?

• Anyone who wants to reduce overdues

• Families with children and lots of books

• Individuals with several library cards

• Anyone who requests a lot of holds

What’s delivered?

• Email and/or RSS alerts before items are due

• Email and/or RSS alerts on overdues and holds

• Consolidated list of yours or your family’s library loans and holds

• Cellphone text message alerts for holds (US and Canada)

• Real-time checking by browser

I love wind turbines both as a great way to make clean power, and as beautiful things to watch. I really don’t buy the stock ‘eyesore’ argument always repeated in articles about wind farms. I often watch our local turbine and find it easily more attractive than a smokestack. So it is with a certain sadness and morbid fascination that I watch this dramatic video of a wind turbine self destructing. The slow motion replays are amazing. You can see how first one blade goes, which throws it off balance and it twists slightly causing the next blade to hit the support tower.

[From Gizmodo]
[via TechEBlog]

Update:
Boing-Boing has an entry on this today with a slightly different video that leaves out the slow motion replay, but runs a little longer showing the aftermath. They also include the explanation: “The braking mechanism that limits the speed of the wind turbine broke during a storm in Denmark. This was the outcome.” and a link to a news article on the failure. Apparantly it was one of two failures last week of Vestas wind turbines in Denmark. Poor maintenance is suspected.

Today while browsing the very fun and informative retro pop culture site Duck Soup Retro I discovered the world of TV Lamps. Apparently when TV’s started getting popular in homes in the 50’s there was concern that watching TV in a dark room would cause eye damage, so the TV lamp was born. These decorative lamps were made to sit on top of the TV to provide some ambient light in the room (long before the Phillips Ambilight TV) and came in a wide variety of styles. These were probably purchased for their decorative value as much as for health concerns. The cool one at Duck Soup includes a painted mountain scene behind what appears to be a small fish tank. Upon some further searching I found www.tvlamps.net which includes more historical information and many photographs of a wide variety of TV lamps.

These wall climbing robots look really cool. I could see how they could be really useful for building inspection or surveillance, although the suction fan seems quite loud in the videos so I don’t know how sneaky you could be with one. They have underwater versions too that I guess could be good at inspecting ship hulls.

See videos and read more [via Engadget]

I for one welcome our new wall climbing overlords

This looks like it could be a comfortable alternative in hot weather, I wonder how quiet it is? They also have a shirt with built in fan.

Read more [via Engadget]

I was struck by the nice design of this clever little folding spoon found in the lid of single serving Skyr (a wonderful Icelandic dairy product similar to yogurt). It clicks into a locked open position to make a very functional spoon, and can be re-folded.

This steam powered R2-D2 by I-Wei (CrabFu) is too cool.

Link

Over at Crabfu SteamWorks an artist named I-Wei Huang is showing off some really fantastic and amazing steam powered model vehicles. He has created walkers, tanks, 4×4 trucks, 6 wheel rovers and more very cool stuff. I have always been fascinated by the basic nature of steam engines. You can make a fire, and it will move your vehicle. I also love the sounds, the deep throaty CHUFF of a really big old steam tractor.

from NewScientist.com news service

“Goggles that simulate a strobe-lighting effect could prevent the nauseating effects of space sickness – and that of more down-to-Earth travel.
[...]

Reschke suggests astronauts could wear the glasses during the early part of space missions to help them adjust. This would be preferable to anti-motion sickness drugs, which frequently make people drowsy.”

Maybe there is hope yet for those of us who can get queasy turning around to fast on an office chair…
LINK