I need someone to explain this to me.

AVR Atmega based PID Magnetic Levitator

magnetic_levitator_atmega_pic

[Davide] saw our recent post on magnetic levitation and quickly sent in his own project, which has a great explanation of how it works — he’s also included the code to try yourself!

His setup uses an Atmega8 micro-controller which controls a small 12V 50N coil using pulse-width-modulation (PWM). A hall effect sensor (Allegro A1302) mounted inside the coil detects the distance to the magnet and that data is used by a PID controller to automatically adjust the PWM of the coil to keep the magnet in place. The Atmega8 runs at 8Mhz and the hall effect sensor is polled every 1ms to provide an updated value for the PWM. He’s also thrown in an RGB LED that lights up when an object is being levitated!

So why is there a kid with a floating balloon? [Davide] actually built the setup for his friend [Paolo] to display at an art fair called InverART 2013!

After the break check out the circuit diagram and a short demonstration video of the device in action!

Oh yeah, those of you not impressed by magnetic levitation will probably appreciate acoustic levitation.

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Levitating Wireless LED Ring

magnetic levitation

Here’s an impressive example of a completely home built magnetic levitation setup… with wireless power transmission to boot!

[Samer] built this from scratch and it features two main sub-systems, a electromagnet with feedback electronics and a wireless power transfer setup.

The ring of LEDs has a stack of neodymium magnets which are levitated in place by a varying magnetic field. This levitation is achieved by using a Hall effect sensor and a PID controller using a KA7500 SMPS controller.

The wireless power transmission uses a Class E DC/AC inverter that operates at 800KHz. Two coils of wire pass the current between the stand and the LEDs.

It’s very similar to a build we featured last year, but it’s a great hack, so we had to share it! Check out the video after the break.

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Defying gravity for new user interfaces

[Jinha Lee] at the MIT Media Lab created a new interface allowing new ways to modify and play with 3D objects. It’s called ZeroN, and it’s nothing short of a futuristic device straight out of Star Trek.

ZeroN is simply a platform for levitating a small spherical permanent magnet in 3D space. It does this by mounting a hall effect sensor on an electromagnet. The hall sensor measure the strength of the magnetic field of the ball every few milliseconds and keeps the spherical magnet levitated. To move the object in 3D space, a few webcams track the ball over the platform and tell the electromagnet to move on a CNC-like x y table.

[Jinha] showed off a lot of cool stuff that is possible with the ZeroN; ping-pong is by far the coolest implementation, but it’s also possible to use the magnetic sphere to demonstrate n-body gravity or as a camera flying around a digital scene.

It’s a really amazing piece of work with an exceptional demo video. You can check that video out after the break. Thanks, [ferdinand] for sending this one in.

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