They probably won’t please the audiophiles, but [KJMagnetics] shows you that can create a pair of speakers with some magnets, some plastic cups, and a bit of magnet wire. Creating speakers out of junk isn’t a new idea, of course. However, there’s something pleasant about the build. Maybe it is the symmetry of the cups or the workbench look of the woodworking.
We couldn’t help but think that this would make a good science fair project or a classroom activity. Especially since there is a good write up on how speakers work and it would be easy to make simple changes to test different hypothesis about speakers. For example, what happens with more or less wire in the coils? What magnets work best? What does best even mean? Is it louder? Less distortion?
Continue reading “Speaker Science Project”
Making an electromagnet is as simple as wrapping some wire around a nail and taping the wire to both ends of a battery. When you’re done, you can pick up some paper clips – it demonstrates the concept well, but it could use some more oomph. [Amazing Science] has done just that, making an “electric train” (YouTube link). All that’s needed is some coiled copper wire, a battery and magnets thin enough to fit through the coils. The magnets snap onto both ends of the battery. Put the battery inside the coil and watch the fun! The electromagnetic force generated by the current moving through the coil pushes against the magnets attached to the battery, pushing the battery along the way.
[Amazing Science] plays with the setup a bit. Connect both ends of the coil together and the battery will travel in a loop until it’s drained. Add a small hill, or even another battery/magnet set to the mix, and watch them go! We may even make a version of this ourselves to take with us to family gatherings this holiday season – it’s simple, fun, and can teach the young ‘uns about science while we swig some egg nog.
Continue reading “[Amazing Science’s] Simple Electric Train”
Whether you use your longboard as transportation or pleasure riding, night-time sessions can be harrowing if you’re screaming through poorly-lit places. The Beamboarder is a solution that is simple to build and easy to throw in a backpack whenever that giant ball of fire is above the horizon.
Boiled down it’s a high-power LED and a Lithium battery. How’s that for a hack? Actually it’s the “garbage” feel of it ([Lyon’s] words, not ours) that makes us smile. An old hard drive with as high of a capacity as possible was raided for parts. That sounded like a joke at first but the point is that early, large drives have bigger magnets inside. You need a really strong one because that’s all that will hold the LED to the front truck of our board. From there it’s a matter of attaching a CREE LED with thermal adhesive and wiring it up to the Lithium pack that has been covered in shrink tube to keep the elements out.
The headlight is under the board, which is courteous to oncoming traffic. Once you pull off this hack we’re sure you’ll want to go further so we suggest wheels with LED POV displays and there’s always the option of going full electric.
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.
Continue reading “Stapler hack fastens infinitely large sheets of paper”
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”