wireless charger

hello guys. i would like to ask if any of you have ideas about wireless charger, specifically a wireless cellphone charger. but me and my teammates don't want to be specific for now. we just want the basic or overview idea of the project. and we we want to know if it is even possible.

p.s
questions ..
1. is it possible to transmit power(?) in wireless medium?
2. if yes. how do we direct that power to a specific device?
3. and is it efficient enough to transmit that power?

frenchneco said:

hello guys. i would like to ask if any of you have ideas about wireless charger, specifically a wireless cellphone charger. but me and my teammates don't want to be specific for now. we just want the basic or overview idea of the project. and we we want to know if it is even possible.

p.s
questions ..
1. is it possible to transmit power(?) in wireless medium?
2. if yes. how do we direct that power to a specific device?
3. and is it efficient enough to transmit that power?

Click to expand...

1. Yes
2. RF radiation
3. No

Cost and size of such a system would make it unpracticable, move on to the next brainstorm Perhaps solar cells on the case of the cell phone would give a little help, but probably not efficient enough indoors to make a difference.

Lefty

Leftyretro said:

1. Yes
2. RF radiation
3. No

Cost and size of such a system would make it unpracticable, move on to the next brainstorm Perhaps solar cells on the case of the cell phone would give a little help, but probably not efficient enough indoors to make a difference.

Lefty

Click to expand...

oh too bad... well, the solar cells are pretty interesting stuff. a self-sustaining cellphone. hmmm.. i'll ask my mates if what they think about the idea.

p.s
i googled the wireless thing up and stumbled in this... this still has a long way to go...

Wireless chargers?
Posted by David Pescovitz, November 15, 2006

Researchers are exploring a phenomenon called "evanescent coupling" as a way to juice up devices powered by rechargeable batteries without connecting them directly to a charger. Unlike electromagnetic induction--the technology that charges electric toothbrushes and early pacemakers--which requires the charger to be very close to the device, this new approach could potentially work at distances of several meters, claim the MIT physicists. From New Scientist:

Evanescent coupling...allows electromagnetic energy "trapped" in a charging device to be tapped by a "drain" mobile device if the two have the same resonant frequency.

"The energy is trapped at source, until I bring a device that has the same resonant frequency close to it. Only then can the energy 'tunnel through'," says (researchers Marin) Soljacic. Crucially, the "charger" only starts powering another device when a compatible gadget comes within range...

Placing one of these wireless chargers in each room of a home or office could provide coverage throughout the building.
https://www.boingboing.net/2006/11/15/wireless-chargers.html

It's also called near field coupling.
Cordless rechargeable toothbrushes have used this method for a long time. There's nothing new about it. Low frequencies are best for near field coupling, far field coupling is best used with high frequencies. Only low frequency magnetic near field coupling is really practical. They call them transformers I think =)

Maybe fit a wind-up generator to the phone, they sell a wind-up torch with a mobile charger cord. wind up your phone for a minute and talk for a couple of hours.

frenchneco said:

hello guys. i would like to ask if any of you have ideas about wireless charger, specifically a wireless cellphone charger. but me and my teammates don't want to be specific for now. we just want the basic or overview idea of the project. and we we want to know if it is even possible.

p.s
questions ..
1. is it possible to transmit power(?) in wireless medium?
2. if yes. how do we direct that power to a specific device?
3. and is it efficient enough to transmit that power?

Click to expand...

1. YES
2. Solar radiation from the sun to solar panel near device
3. YES

Solar radiation comes all the way from the sun wirelessly.
Is this method too obvious to be included in your "don't want to be specific for now" specification?
Klaus

Super_voip said:

Maybe fit a wind-up generator to the phone, they sell a wind-up torch with a mobile charger cord. wind up your phone for a minute and talk for a couple of hours.

Click to expand...

I doubt it, probably wind it up for twenty minutes to talk for two minutes.

You want do do the same as Nikola Tesla wanted to do :-
http://www.tesla.org/

frenchneco said:

hello guys. i would like to ask if any of you have ideas about wireless charger, specifically a wireless cellphone charger. but me and my teammates don't want to be specific for now. we just want the basic or overview idea of the project. and we we want to know if it is even possible.

p.s
questions ..
1. is it possible to transmit power(?) in wireless medium?
2. if yes. how do we direct that power to a specific device?
3. and is it efficient enough to transmit that power?

Click to expand...

Wireless systems also use wire. in the form of tuned coils.

If you want to get enery from wireless, go to the vicinity of a High poer Tx station. put a small aerial and rectify the signal and use the resultant DC to charge the battery. warning- Take proper care of illegalality-- skin burns - and damages to cellphone itself some times.

I did see the article about the "researchers" who are selling the idea. It seems the signal knows what appliances need power and only goes only to them, the signal is not 'radiated'

thanks

thanks a lot guys for the ideas. it seems harder than i thought. probably i'll get back to this problem after i finish my units in wireless communications. =)
but i'm still open for any suggestions.
light a bulb in my head.

https://en.wikipedia.org/wiki/WiTricity
https://en.wikipedia.org/wiki/Evanescent_wave_coupling

It's nothing new and isn't hard to do. I've done this myself using two resonant circuit consisting of two ferrite rods copper glased wire wrapped round them and capacitors in parrallel, I could power an LED from 300mm away.

Hero999 said:

https://en.wikipedia.org/wiki/WiTricity
https://en.wikipedia.org/wiki/Evanescent_wave_coupling

It's nothing new and isn't hard to do. I've done this myself using two resonant circuit consisting of two ferrite rods copper glased wire wrapped round them and capacitors in parrallel, I could power an LED from 300mm away.

Click to expand...

cool! 300mm? is that the max distance? can you send me the circuit? maybe i can get any ideas related to my proj.

I didn't even bother drawing the circuit.

I used two pieces of AM radio ferrite rod.

I wound coils of the same known inductance on each.

Connected close tolerance 2.5% high quality ceramic capacitors and trimmer capacitors in parrallel with each coil.

Connected an n-channel MOSFET as a low side driver in series with one of the tuned circuits.

I calculated the resonant frequency of the tuned circuits. and conencted the gate of the MOSFET to a signal generator running at the resonant frequency at 50% duty cycle.

I connected two LEDs in reverse parrallel to the other tuned circuit.

I then adjusted the trimmer capacitors on both tuned circuit to make the LEDs glow from as far away as possible.

Hero999 said:

I didn't even bother drawing the circuit.

I used two pieces of AM radio ferrite rod.

I wound coils of the same known inductance on each.

Connected close tolerance 2.5% high quality ceramic capacitors and trimmer capacitors in parrallel with each coil.

Connected an n-channel MOSFET as a low side driver in series with one of the tuned circuits.

I calculated the resonant frequency of the tuned circuits. and conencted the gate of the MOSFET to a signal generator running at the resonant frequency at 50% duty cycle.

I connected two LEDs in reverse parrallel to the other tuned circuit.

I then adjusted the trimmer capacitors on both tuned circuit to make the LEDs glow from as far away as possible.

Click to expand...

got that! i will try to make mine. i'll just post something if anything comes up. tnx dude! btw, ur from what country?

Hmm... it says Location : England...

Yup ! I think he is from England.

Well, the circuit you're talking about could be found on any rechargeable electric toothbrush. To mantain proper isolation in the humid enviroment, the transmission between the base and the toothbrush is made using two coils, not metal electrodes. The problem is poor range, the coils are just separated by milimeters of plastic.

If you want power transmission, why not building a tesla coil, and put fluorescent tubes around?

**broken link removed**

Edit: You don´t even need a tesla coil, I remember a shop where a big but simple transformer (120 to 12, originaly used to power halogen lamps) was used to remotely power fluorescent tubes hanging on nylon cords some meters away

Menticol said:

Edit: You don´t even need a tesla coil, I remember a shop where a big but simple transformer (120 to 12, originaly used to power halogen lamps) was used to remotely power fluorescent tubes hanging on nylon cords some meters away

Click to expand...

I don't think it can have been a 12V halogen transformer?.

is it possible to transmit power really.can you give some information abt this?

Dileep Kumar said:

is it possible to transmit power really.can you give some information abt this?

Click to expand...

No it's not - not with any degree of efficiency or over worthwhilse distances.