Wednesday, March 18, 2015

3D printed wireless Nikola Tesla desk lamp

Nikolas Tesla, the biggest inventor of the last two centuries, was known throughout the world for his role in developing today's electrically-powered world. He has been gaining more credit an appreciation in recent years, especially in the engineering community.

Meanwhile, he is becoming something of a role model and inspiration for some, such as electronics designer David Choi from Long Island, NY. David is a physics graduate from Wesleyan University recently began dabbling in 3D printing. As he explains, Tesla has always intrigued him – both as a person and as an inventor. "Tesla, the inventor of the radio, AC motor, and a multitude of important everyday inventions, had been forgotten in time. Recently brought back into the home through Tesla Motors, but people still fail to realize Tesla the inventor and electrical genius is much more than just a modern car company," David says. "He figured out how to wirelessly transmit power. Imagine a world without wires. This was his dream."

To emphasize his respect for the man, David has already named his cat after Tesla, but has recently been taking things a bit further. For as a tribute to his hero, David has developed a 3D printed lamp that functions on one of the core principles of Tesla’s inventions: wireless transmission of electricity. To harness that principle, David has created a wireless power table filled with 3D printed components that is capable of powering a light bulb. "My idea was to wirelessly power whatever I wanted on this table. Powering a lightbulb was my proof of concept--if I could power a light, I could power almost any household item," David explains and as you can see, its working very well.




But of course, you’ll need some components (especially the coils) that are beyond the power of a desktop 3D printer and David began his project by focusing on those. "The receiving coil is a spiral inductor as can be seen in the base. There's a certain beauty to air-core inductors and it has to do with their simple construction--a loop. After doing my calculations, I realized I needed to construct a spiral air-core inductor to match to the 25W lightbulb load," David says.
These coils are the core of the system, alongside dual RF transistors (MRF150), and function either as a transmitter or as a receiver. "The first coil transmits power magnetically to the secondary coil. This secondary, along with the primary coil, both transmit power magnetically to the third receiving spiral coil," David explains. "The transmitter is a center-tapped, double wind, 0.34uH coil. This tank circuit is tuned to 6.5MHz. This first coil is magnetically coupled to a much larger secondary coil which is approximately the diameter of the table (2.5x2.5ft). This secondary coil's purpose is to store greater amounts of reactive power when tuned to resonance at 6.5MHz."
The fourth coil (the receiver), meanwhile, consists of a spiral coil and a 42pF capacitor which tunes it to resonate at 6.5MHz and is directly wired to the lightbulb. "By having two coils resonating at the same frequency, the distance of coupling between them can be greatly increased. To capture this resonating reactive power is a single loop coil that follows the circumference of the spiral inductor," David explains. This will enable the lightbulb to receive power at 6.5MHz vs the tradition 60Hz (or 50Hz). "This high frequency aides in increasing the quality factor of the coils and thus the coupling between them," David adds.
The coils itself are made from copper tubing. To harness the fluctuating magnetic field that is being generated, David designed a circular loop inductor around the spiral inductor. "This has a wire that attaches to the bulb itself. I did not want any wires visible so one of the lamp legs serves as a conduit for the wiring. The spiral coil receives its power wirelessly through the table which has a power transmitter built into its underside."
Aside from the electronics, only the bulb itself hasn’t been 3D printed. That means this project is easily reproducible and fortunately David has shared all of his designs on Thingiverse to enable everyone to harness the potential of Tesla’s inventions. To make these parts, David relied on his MakerBot Replicator 5thGen 3D printer. All parts have been 3D printed in PLA with 15% infill and a resolution of 0.2 mm. The results can be easily assembled with just a little glue. ‘After printing, all I had to do was lay the copper tubing into the coil form. This is easy for anyone to recreate as traditionally, large coils such as these are handmade at home and it is difficult to create them repeatedly with the same dimensions and ultimately inductance,’ David explains.
All in all, this is a very fun project for everyone looking for a bit of unusual electric experiences and a perfect tribute to a great inventor who should not be forgotten. It should be highly reproducible with parts you have laying around and it should work with most typical light bulbs. David intentionally went for a vintage Tesla bulb reconstruction for the theme, but that’s a matter of personal convenience. "Were I to have chosen an Edison or Marconi bulb, Tesla would be rolling in his ashes," he adds, but I think you’ll get away with it.

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