Chief Delphi - witricity legality?

Chief Delphi (http://www.chiefdelphi.com/forums/index.php)

- Electrical (http://www.chiefdelphi.com/forums/forumdisplay.php?f=53)

- - witricity legality? (http://www.chiefdelphi.com/forums/showthread.php?t=66317)

Re: witricity legality?

Quote:

Originally Posted by Qbranch (Post 726187)

We put a circuit in line with the power supply...

That violates <R53> as I read it. You might successfully argue that it's a non-functional decoration and thus not part of the "robot control system", but it looks to me like it's still covered by the "other sensors or circuits" phrase.

Re: witricity legality?

Quote:

Originally Posted by Alan Anderson (Post 726420)

I would venture that "altering the power pathways" essentially means that nothing is supposed to go in between the breaker panels and the Victors/Spikes/RC, or between the Victors/Spikes and the motors. What Qbranch describes doesn't sound like it's altering the path to some circuit... the supply/display combo IS the circuit. I can't understand how <R53> could be read to outlaw this... there are plenty of custom circuits teams have used that derive power from the 12VDC system, but end up using something other than 12VDC at the end.

Re: witricity legality?

Quote:

Originally Posted by XXShadowXX (Post 726203)

one debate that is poping up every page that i would like to settle is that witricity is not
radio waves
anykind of standard electromagnetic wave (radio, micro, infared, light, UV, Xray, gamma)
it will not be used to control robot
it will not interfere with body
it will not heat up body
the power for the coils will be from the battery not external.

i hope this clears up any future comfusion

From this post I will assume that witricity is magic not electromagnetic induction.

Everything I know about electromagnetic induction indicates that using two inducting coils would both interfere with and heat the body of the frame. Take any high school physics book and look up eddy currents. The principle is essentially that any piece of metal contains hundreds of conducting loops which will all form currents when in the presence of a changing magnetic field. Such loops will generate heat and suck power from the desired application. You will notice that there was no nearby metal in the M.I.T. test and that the only barrier used was a WOODEN BOARD.

Re: witricity legality?

ok ok we won't use it.

Re: witricity legality?

Quote:

Originally Posted by Alan Anderson (Post 726420)

Well... three regional inspections, from three different inspectors, in three different cities think different. :]

Re: witricity legality?

There are various rules that may come into play on this one. Solenoid actuators and transmitting devices other than the radio modems and a specific signaling device for the hybrid mode are specifically prohibited under current rules. And as Alan has pointed out, R53 most certainly applies. As to some of the previous posts, Tesla coils included, all are fairly lossy devices and/or require rather large electromagnetic fields to operate. Although cool and an interesting way of supplying power to rotating mechanisms, they are likely just too inefficient for use on a robot. Please check into the 60 watt light bulb and look closely at the power input required to light the bulb.
BTW, the circuit used to keep the display from blanking for the Kilobytes is considered a custom circuit and does follow the robot rules in that is specifically does not control any motors or actuators on the robot and thus follows R53. In a similar fashion, the power supply that some teams use to power decorations like the CCFL tubes also modifies the power supply but does not connect to any control on the robot.

Re: witricity legality?

Quote:

Originally Posted by XXShadowXX (Post 726492)

ok ok we won't use it.

ok people!

Re: witricity legality?

Ok, I have had a chance to do a little research on the experiment and this is what I found. The stated efficiency is about 40% and the team claims that they will be able to develop a commercial system that will meet FCC safety standards. The demonstrated system ran at 10 MHz.
A few things came to mind while I was reading some of the articles. 10 Mhz is already used for a variety of very important wireless governmental services such as WWV time standards and GPS synchronization signals. Just above this frequency is an amateur radio band that shares the spectrum with other services. So there is more to consider than just safety issues.
As far as use on a robot, this system is being developed for delivery of power and has no provision for tranmsission of control signals, although there are other devices that do that very well. In the future this might be a pretty cool thing to have on the robot if certain other problems are addressed. Keep thinking, we might see this someday.

Re: witricity legality?

Quote:

Originally Posted by XXShadowXX (Post 726492)

ok ok we won't use it.

Sounds like you got the message...but that won't stop everyone else from discussing it to death! :)

Re: witricity legality?

Quote:

Originally Posted by squirrel (Post 727698)

Sounds like you got the message...but that won't stop everyone else from discussing it to death! :)

y'know i think it would be great to use but it is decades ahead of time. I will try to build a prototype of it over the summer if it works then you will hear the post.

all i need alot of eletrical stuff...

Re: witricity legality?

Quote:

Originally Posted by XXShadowXX (Post 727718)

I will try to build a prototype of it over the summer if it works then you will hear the post.

all i need alot of eletrical stuff...

Don't forget that RF heating of body parts is a well established fact. Start reading about RF and coupled circuits before you jump in. If the numbers can be believed, to deliver 60 watts at the light bulb at 40% efficiency, then the transmitter had to be able to deliver at least 150 watts to begin with. That is 50% higher power than the transmitters many ham operators use to communicate around the world. Interference is something that you will find brings the FCC knocking on your door.

Re: witricity legality?

Quote:

Originally Posted by Al Skierkiewicz (Post 727727)

If the numbers can be believed, to deliver 60 watts at the light bulb at 40% efficiency, then the transmitter had to be able to deliver at least 150 watts to begin with. That is 50% higher power than the transmitters many ham operators use to communicate around the world. Interference is something that you will find brings the FCC knocking on your door.

could be a very interesting conversation.

"I was trying to apply pioneering technology to a robot to give us a competive edge in FIRST, with a new type of wireless crab drive."
"Well your disrupting ICBM guidance."
"Sorry."

it wouldn't work like that. Anyways i think the current is magentic not radio, so i don't think that it will interfere. Also when Popsci (Popular Science) ran an article on Witricity they said that it does not interfere with the human body. But i will have safety glasses on anyways.

Re: witricity legality?

i believe this article should clear up any confusion about witricity.

Quote:

In 2006, Marin Soljačić and other researchers at the Massachusetts Institute of Technology applied the near field behaviour well known in electromagnetic theory to a wireless power transfer concept based on coupled resonators.[8][9][10] In a short theoretical analysis they demonstrate that by sending electromagnetic waves around in a highly angular waveguide, evanescent waves are produced which carry no energy. If a proper resonant waveguide is brought near the transmitter, the evanescent waves can allow the energy to tunnel (specifically evanescent wave coupling, the electromagnetic equivalent of tunneling[citation needed]) to the power drawing waveguide, where they can be rectified into DC power. Since the electromagnetic waves would tunnel, they would not propagate through the air to be absorbed or dissipated, and would not disrupt electronic devices or cause physical injury like microwave or radio wave transmission might. Researchers anticipate up to 5 meters of range for the initial device, and are currently working on a functional prototype.[8]

On June 7, 2007, it was reported that a prototype system had been implemented. The MIT researchers successfully demonstrated the ability to power a 60 watt light bulb from a power source that was seven feet (2 meters) away at roughly 40% efficiency.

"Resonant inductive coupling" has key implications in solving the two main problems associated with non-resonant inductive coupling and electromagnetic radiation, one of which is caused by the other; distance and efficiency. Electromagnetic induction works on the principle of a primary coil generating a predominantly magnetic field and a secondary coil being within that field so a current is induced within its coils. This causes the relatively short range due to the amount of power required to produce an electromagnetic field. Over greater distances the non-resonant induction method is inefficient and wastes much of the transmitted energy just to increase range. This is where the resonance comes in and helps efficiency dramatically by "tunneling" the magnetic field to a receiver coil that resonates at the same frequency. Unlike the multiple-layer secondary of a non-resonant transformer, such receiving coils are single layer solenoids with closely spaced capacitor plates on each end, which in combination allow the coil to be tuned to the transmitter frequency thereby eliminating the wide energy wasting "wave problem" and allowing the energy used to focus in on a specific frequency increasing the range.
http://en.wikipedia.org/wiki/Wireles...nant_induction

there you go

Re: witricity legality?

Quote:

Since the electromagnetic waves would tunnel, they would not propagate through the air to be absorbed or dissipated, and would not disrupt electronic devices or cause physical injury like microwave or radio wave transmission might. Researchers anticipate up to 5 meters of range for the initial device, and are currently working on a functional prototype.[8]

this is the important part...

now can we have a more informed talk about this crap.... (not crab).

Re: witricity legality?

Quote:

Originally Posted by XXShadowXX (Post 727737)

could be a very interesting conversation.
Anyways i think the current is magentic not radio, so i don't think that it will interfere.

Also when Popsci (Popular Science) ran an article on Witricity they said that it does not interfere with the human body. .

Radio is EM, as is light, x-rays, gamma rays etc, the only difference is frequency.

Do you know what issue of PopSci the article was in, I don't remember reading it but I would like to. Also PopSci is not always the best resource.