Re: witricity legality?
 

I'd like to apologize for my rather... short post about feasibility. As an RF Engineer Apprentice, I'd like to let you know that this sort of stuff is actually a lot of fun.

This specific experiment might not be feasible, but there is a lot of other cool stuff to do in this vein. RFID is a very very similar principle. Take a look!

Re: witricity legality?
 

Hmm, lots of info in this thread and a neat idea.

Keep in mind that the power curves of most FRC motors extend upwards to at least ~150watts. If power out = (efficiency) * power in, where efficiency is less than 100%, then it takes more than 150watts of power to make the motors run. Add in the efficiency of the witricity system and you're faced with coming up with a way to power 5-6 60 watt lightbulbs at once instead of just one.

I'm not going to tell you it's impossible, because actually I think it is. Is it practical in FRC with your drive train, compressor, and other possible motors running? That's what experimentation is for, so I don't know. It's hard to say if the battery output could keep up for a full 2:15. Even with the '07 or '08 rules, the GDC may have accomodations in the rules to make it legal in '09 (but don't get your hopes up).

Re: witricity legality?
 

You are correct, WiTricity is physically possible. however, probably incredibly destructive. Look at the nature of electricity and plasma. Plasmas (this includes fire and electricity) Plasmas in their nature are designed to destroy everything they get into contact with. The amount of energy require to transfer electrical potential is incredibly powerful, and can destroy not only human cells, but electrical circuits. everything in the path of these waves will be instantly destroyed. You can essentially kiss all of your electronic components good bye. And no, these cheap little electronic devices aren't made to withstand such a destructive force. Hope this clears up any notion to use such an experimental procedure.

Re: witricity legality?
 

I need to correct a little here:

1> Witricity is RF, which is the transfer of electricity (electrons) through a medium in a specific frequency band. It is not conversion of that electricity (electrons) into plasma (charged ions).
2> Plasma is not inherently destructive. There are many factors that go into what plasma does. Energy levels, frequency, material being affected, etc. I use plasma all the time in surface treating applications where I work.
3> RF (like Witricity) is also not inherently distructive. You have RF going through you everyday. Cell phones, WiFi, Radio (including the RC radio), RADAR all use RF. There's also natural RF generators (our sun is a good example).

Now I'm not saying that Witricity would not be destructive. Properly implemented and controlled it could be very useful and nondestructive. The key is an understanding of the effects that the fields will have on the local enviroment and nearby objects. And "those cheap little electronic devices" ... you'd be surprised how much RF they can handle (at specific frequencies).

Re: witricity legality?
 

Daniel,
One small correction, we are talking about electromagnetic energy in a certain frequency band.

Re: witricity legality?
 

You are correct.

I don't generally differentiate between electromagnetic energy and electrcity because any movement of electricity within a medium creates a magnetic field (so for me it's an assumed thing).

Again, you are correct.

Re: witricity legality?
 

I havnt looked into this one bit, but does any one know where the power loss comes from?

After a quick wiki search...

It seems as if this technology is similar to transformers. either steup up or step down, so if the coils were identical, then theres no ups or downs but a direct transfer of energy via electromagnetic field. So...this makes me think that the 40% efficiency @ 7feet away conducted by MIT could have been more efficient if the two coils were close to one another....similar to a transformer. Is the high frequency necessary? I can feel the 60Hz "buzz" from my desk lamp if I put a metal object close to the base of the lamp. It doesnt seem to be affecting anything.....I will try a simple coil test right after I publish my post, Ill repost with the results form my Mastercraft Multimeter.


BRB!

Re: witricity legality?
 

Okay, so I see why they dropped the Witricity. As far as I can see, I didnt get any voltage, but I did get some current, 130mA was the average. As soon as I moved about 2cm awway I was down to only 20ma....Not a very good power supply... thats the end of that..

Re: witricity legality?
 

June,
There are a variety of places where the power is lost. Turning RF into an effective field is tough enough but then you add to that the power that is lost by not coupling all of that field to the receiving coil. The inefficient coupling between the coils due to a lack of focus of the field and the varying load on the receiving coil all add up as well. Certainly placing the coils closer together would help. The RF is used to make the coils small and light enough to be a practical demo. Lower frequencies would work but the coils become significantly larger for the same efficiency.