Watch Glowing Light Bulb Floating In Mid-Air!
Monika Bhati, EFY News Network
(Friday, July 06, 2012 11:09:41 AM)
A combination of the two technologies--wireless power transfer and magnetic levitation--does the trick.
Friday, July 06, 2012:
Watching a thousand glowing light bulbs floating in mid-air, is no longer a distant reality. It could now be possible thanks to a project by Chris Rieger, an electrical engineering student currently enrolled at University of Queensland. What did the trick for Rieger was a combination of the two technologies called wireless power transfer and magnetic levitation. While he modified an existing circuit built by Eric Taylor for levitating the bulb, he made changes to the circuit design by Marko for building a wireless power transfer.
Sharing the details of the project, Rieger says: "This is a project I've been working on for about six months now next to my regular studies. It is a levitating light bulb. This project came to life when i saw Jeff Lieberman's implementation of it a few months before starting. I was fascinated and started research on building my own, reading many academic papers and spending long nights reading up on pretty much every project which included wireless power transfer or magnetic leviation. What I found is that there are many many existing projects of both, but only a few have combined both these technologies. Once you have both working, it's really just a matter of overlaying them. The high frequency magnetic field generated from the wireless power transfer circuit does not effect the leviation aspect of the build."
He adds: "For the levitation system, I ended up slightly modifying an existing circuit built by Eric Taylor. My configuration is slightly different and am using a 3-pin linear hall effect sensor from RS components to act as the feedback mechanism. I opted for a 1.325mV/g sensor (the smallest sensitivity i could find), as the magnetic flux it was sensing was maxing out the reading on others. If you are looking to build one, this circuit is simple and works with only slight modification depending on the input sensor you have. The drive coil I'm using is 300 metres (1kg) of 20awg wire. It draws about 0.2 - 0.25A when stable at 12V. It doesn't seem to heat up over time, unless the light is not levitating, in which maximum (0.8A) current is driven through the coil."