An Australian student has created a levitating lightbulb that powers itself wirelessly.
Chris Rieger, who's studying electrical engineering at the University of Queensland, uses the same principle as wireless phone chargers to power the LED device, which floats thanks to a high frequency magnetic field.
"Efficient wireless power transfer was the more painful part of this project. I started off with 555 oscillators used by a few people, but the power transfer is not strong enough and the waveform was horrendous," he says.
"For my final design I must give credit to an old but very simple design by Marko. I have modified his circuit slightly to better limit the heat generated by this circuit. It runs at pretty much exactly 1Mhz pulling 0.5A at 12V. Although this consumes around 6 watts, after running it for a half an hour, the small heatsinks are merely warm."
The wireless power receive circuit is a simple LC circuit tuned at exactly 1Mhz.
Riger says he's working on improvements to his levitator that should give itgreater strength and a better control system, based on a 3.5kg copper drive coil working at 24v, and wound on a better core.
He's also hoping to add computer-controlled height control and light dimming, through the use of a microntroller.
"My goal is to eventually build a small run of kits (~10) complete with plexiglass case and an authentic looking light bulb. This would probably take 6-9 months to put together," he says.
There's a video below.