Learning how magnets and magnetic fields work is one thing, but actually being able to measure and see a magnetic field is another thing entirely! [Stanley’s] latest project uses a magnetometer attached to a robotic arm with 3 degrees of freedom to measure magnetic fields.
Using servos and aluminium mounting hardware purchased from eBay, [Stanley] build a simple robot arm. He then hooked an HMC5883L magnetometer to the robotic arm. [Stanley] used an Atmega32u4 and the LUFA USB library to interface with this sensor since it has a high data rate. For those of you unfamiliar with LUFA, it is a Lightweight USB Framework for AVRs (formerly known as MyUSB). The results were plotted in MATLAB (Octave is free MATLAB alternative), a very powerful mathematical based scripting language. The plots almost perfectly match the field patterns learned in introductory classes on magnetism. Be sure to watching the robot arm take the measurements in the video after the break, it is very cool!
[Stanley] has graciously provided both the AVR code and the MATLAB script for his project at the end of his write-up. It would be very cool to see what other sensors could be used in this fashion! What other natural phenomena would be interesting to map in three dimensions?
Continue reading “Measuring Magnetic Fields with a Robotic Arm”
It’s not called the infinity stapler, but we think it should be. This magnetic hack allows you to use a plain old stapler to fasten very large pieces of paper.
The limiting factor has always been the distance between the stapler’s hinge and where the staples come out. To get around this, the crimped connections between the base and the dispenser were drilled out. Larger holes were then drilled in both the top and bottom halves to accept a set of magnets. These were held in place temporarily with some tape while the super glue had time to set up.
The result is two halves which are placed on either side of the over sized paper. The magnets are responsible for aligning the staples with the die which bends them to their final shape. The whole process is shown in the video clip after the break.
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Giant fresnel lens is dangerous fun
Here’s an interesting, and rather dangerous, use for those old big screen TVs that are frequently listed for FREE on Craigslist. With the lens from the old TV built into an adjustable wooden frame, [Grant] was able to melt a stack of pennies, instantly burn wood, melt spots in concrete, and serve his family a cooked egg… Cool.
Projection mapping app helps create hologram like performance stage
[Aimino] used an iPad, a mobile projector, and a mosquito screen to create a trippy hologram like stage. It might not seem like much at first, but it’s actually a pretty interesting effect. Watching the video makes me wonder what other applications this could have in the near future.
The world’s strongest magnet
At a cost of over $14 million dollars and weighing in at 35 tons, the 45 Tesla Hybrid is the strongest DC magnet on Earth. It’s powerful enough that the film crew couldn’t even safely get in to take footage of it. Over half of their camera tapes were wiped clean just while being in the same facility that houses it!
Virtual Body chair uses 4 of our 5 senses
Created in the hopes of providing a VR experience for seniors with mobility problems who can no longer travel the world, Tokyo Metropolitan University’s Ikei Laboratory presents the ‘Virtual Body’ exhibition. Included are a 3D monitor, a pair of headphones, a fan to create breezes and spread scents, a chair that moves and vibrates, and moving foot pedals.
Iron Man laser gauntlet pops balloons with ease
If you’re an Iron Man fan with disposable income, you might want to check out this functional full metal laser gauntlet. Built from scratch using no blueprints or guides, [AnselmoFanZero] sells them for around $3K USD.
We admit that this project doesn’t have very many details available, but it was just too neat for us to pass up. It’s a small linear motor which [ligonapProduktion] built after seeing a very brief description of a commercially available version.
The video after the break shows him testing the motor. In this screenshot he’s holding the center shaft while the coil assembly moves back and forth. But it works with a stationary coil moving the rod as well. The motor is basically a modified solenoid. There are sixteen neodymium magnets inside the shaft. The set of four coils is driven by an ATtiny44. Just like a stepper motor, energizing the coils in the correct order pushes against the rare earth magnets creating motion.
We’re not sure if he has any use in mind for this build. For us we just like to see the concept in practice (we feel the same way about a homopolar motor build).
Continue reading “Building a linear motor”
[Keith] got his hands on a few grandfather clocks. Apparently the price tag is greatly reduced if you are able to get them second-hand. The mechanical timepieces require weekly winding, which is a good thing since you’ll also need to correct the time at least that often. But this drift got [Keith] thinking about improving the accuracy of these clocks. He figured out a high-tech way to adjust the timepiece while it’s ticking.
The first thing he needed was a source of super-accurate time. He could have used a temperature compensated RTC chip, but instead went the more traditional route of using the frequency of mains power as a reference. The next part of the puzzle is to figure out how to both monitor the grandfather clock and make small tweaks to its pendulum.
The answer is magnets. By adding a magnet to the bottom of the pendulum, and adjusting the proximity of a metal plate positioned below it, he can speed up or slow down the ticking. The addition of a hall effect sensor lets the Arduino measure the rate of each swing and calculate the accuracy compared to the high voltage frequency reference.
We guess we’re glad to hear that other also suffer from the phantom shower curtain liner. On occasion the shower curtain will start closing in on us around the bottom of the shower. We’re not certain of the phenomenon that causes it. Perhaps it’s static electricity like when a comb repels a stream of water. It could be an issue with rising air though… who know. But [Sk84life0129] has had enough of it. He figured out a magnet-based solution to stop the shower curtain from groping him.
You can buy curtain liners that have magnets in the bottom of them to help prevent this. But this is an acrylic tub — not one that’s porcelain-coated cast iron like they used to be — so that’s not going to do any good. Instead, a pair of magnets from an old hard drive were glued to the shower surround. A couple of galvanized bolts had their heads sawn off, and were sewn into pockets in the shower curtain. These hold it taught while you scrub your body, preventing it from reaching out for a close encounter.
Making computers interact with physical objects is a favorite of the HCI gurus out there, but these builds usually take the form of image recognition of barcodes or colors. Of course there are new near field communication builds coming down the pipe, but [Andrea Bianchi] has figured out an easier way to provide a physical bridge between computer and user. He’s using magnets to interact with a tablet, and his idea opens up a lot of ideas for future tangible interfaces.
Many tablets currently on the market have a very high-resolution, low latency magnetometer meant for geomagnetic field detection. Yes, it’s basically a compass but Android allows for the detection of magnets, and conveniently provides the orientation and magnitude of magnets around a tablet.
[Andrea] came up with a few different interfaces using magnets. The first is just a magnets of varying strengths embedded into some polymer clay. When these colorful magnetic cubes are placed on the tablet, [Andrea]’s app is able to differentiate between small, medium, and large magnets.
There are a few more things [Andrea]’s app can do; by placing two magnets on an ‘arrow’ token, the app can detect the direction in which the arrow is pointing. It’s a very cool project that borders on genius with its simplicity.
You can check out [Andrea]’s demo video after the break.
Continue reading “Tablet interacts with magnets, how does that work?”