Wireless Power.

S

smokelight101

Member
Hey Everyone!,
For my senior project I have been leaning towards a wireless power. I have only read about the basics so far but powering a led or (maybe a picaxe?) looks possible. I plan to research the subject further but i was wondering what you guys thought about it. Has anyone tinkered with this. Any tips.

Thanks you guys for reading.
 
L

lanternfish

Senior Member
Any tips? Yes, help us out by linking to some of the material you have been reading (if it is on the web). Giving a better descrition of what you are planning would also help.

Checked your blog. An 08M can communicate with a PC. Use serin/serout commands and a suitable interface.

Cheers
 
S

smokelight101

Member
I originally intended to use the program cable to communicate, I believe the 8m can not receive via the prog cable. I did have alot I/0 pins. I'll get them articles up pronto. Thank you for reading my blog
 
M

manuka

Senior Member
smokelight101: Senior year - is this High School or University ? Best you specify your age, resources, electronic experiences & project time frame.

The god of wireless power was of course Tesla-have you read up on his late 19th century work? What energy transfer ranges did you have in mind ? It's feasible to power a LED at very close ranges, but forget it at decent distances unless you've kW/MW at your disposal.

IMHO environmentally scavenged power, perhaps from nearby radio stations etc, may have more mileage !

Stan.
 
Last edited:
D

Dippy

Moderator
I haven't studied any links but there have been zillions of experiments with wireless power over the last decades.

Other than a torch/flasglight and solar panel you will have to look into RF power - with the potential hazards an illegalities involved.

You may have to study a bit of antenna theory. But you have to be very cautious with this sort of stuff.
I'm not going into Doom & Gloom mode, but be careful.

If I were going to do this I would consider the microwave approach.
Upside, they can be sort of focussed with a horn or a lens.
Downside, severe mischief or injury potential.
NOT to be trifled with by novices or schoolboys.
Calculations (yes, calculations!!) and good construction/materials is crucial.
And if you can't get hold of an expert to help you then forget it.

If you decide to dabble with this then please let me know where you live so that I can avoid your address by several miles :)

(I saw a TV programme t'other night showing an antenna based 'solar' panel for 'collecting' energy from infra-red. Principle sounds good, but starngely they couldn't demonstrate it.... maybe it suffered the same problem as a Stealth Bomber did at a Farnborough Airshow about 10 years ago.)
 
hippy

hippy

Ex-Staff (retired)
Sony have just recently announced their researchers have successfully managed to power a 60W TV without wires, though they acknowledge this is just early stages and not perfect; 25% losses etc.

The technique of 'inductive coupling' or sucking power out of air is not new and can work - I recall a story ( though don't know how true ) of someone living near Brookman's Park in the UK, home of a powerful BBC radio transmitter, wrapping miles of wire extracted from transformers around their loft and using that as a power source. The radio black-spot purportedly created had the Radio Authority come down on them pretty quickly.

I've no real experience of inductive coupling other than building a transmitting coil and seeing a receiving coil pick-up the signal on a scope.
 
M

moxhamj

New Member
ha ha ha hippy. I have half of Adelaide's power supply go through my property via a high tension cable (approx half a million residents) and a colleague of mine runs the high voltage distribution company. I ran the idea past him once of running some pickup cables parallel to the high tension wires and using a transformer and sucking the power out of the aether. Q: Would they notice? A: Within 24 hours!

No power is *free*.
 
hippy

hippy

Ex-Staff (retired)
Ditto for leeching power off incoming telephone landlines. Very small quanities could perhaps be obtained but anything significant or usable is likely to be seen as a fault condition and be investigated.

I recall some telephone companies weren't adverse to sending high voltage energy pulses down the lines to burn away suspected corrosion. POTS equipment would be designed and expected to tolerate that, but anything not expecting it could disappear in a puff of smoke.
 
P

papaof2

Senior Member
The feasability depends on how much power and how far away.

Short distance wireless but physically close inductive power coupling is used in some current commercial products.

rechargable toothbrush (on the How Do They Do That? series) - Possibly a couple of watts, using a coil in the brush handle that sits inside a coil in the base unit.

laptop (new Dell Latitude Z: http://news.idg.no/cw/art.cfm?id=06BBDE03-1A64-67EA-E4C13E3A20C019B4 ) - Probably in the 60-90 watt range; I haven't seen one in person, so don't know how their inductive coupling pieces fit together.

John
 
D

Dippy

Moderator
Oh, if you were talking about tiddly inductive stuff then that is kid's stuff.
Physics lesson for 11 year olds.
I thought you were on about a few metres and something more than a little LED.
 
M

manuka

Senior Member
Inductive coupling naturally is a very close proximity technique- it's amazing that even cordless toothbrushes charging is feasible- & long range "wireless power" is largely the stuff of science fiction & back yard tinkerers. Stealing even a few Watts from passing power lines is worthy Mythbusters material => http://www.youtube.com/watch?v=6hs9Gz4JuhI. The BBC mentioned a half baked 6.4MHz resonant approach some years back (http://news.bbc.co.uk/2/hi/technology/6129460.stm ) that was thought capable of a few metres range. AFAIK it however went no further...

Very high freq. RF radiation beamed from any distance certainly can be received & collected with parabolic dishes, but the overall system merits are questionable. Although tempting to explore & ponder, especially with microwaves, such boring issues as safety may doom even simple investigations. "Powersat" satellite power plants, beaming from geostationary orbit (22,300 miles, 35,700 km), back to earth could be be received via enormous "rectenna" farms with good efficiency, but the overall cost and complexity is mind boggling.

Mmm- RFID ? RFID of course is a wireless technology & offers ranges to a few metres at usually ~13.56MHz, but it's intended for ID rather than power transfer. Aside from books, traffic tolls & retail items, innovative implants in golf balls, playing cards and even casino chips have arisen. Developments have been rapid in recent decades, & RFID "dust" has even been developed.

IMHO,although only a daytime resource, solar panels may be abundantly more appealing for a simple "wireless power" project. Panel efficiencies are only a mere ~10%, but the incident sunlight is free for the taking & PV prices are just an attractive US$5-$10 a Watt. Their availability & ease of use mean even a kid can safely investigate small scale photovoltaic sourced wireless power. Gloss up a project with mad scientist titles like "Scavenged thermonuclear wireless energy transfer" plus lots of simple path loss calculations, & you'd really catch the audience. You may even score a governemnt grant!
 

Attachments

Last edited:
M

MartinM57

Moderator
So being an inductive coupling newbie ... how could I get a serial link working through the side of a plastic case (2mm?). For example, plugging the jack plug end of an AXE027 into something that you then hold against the side of a unit (a bit like a doctor with a stethoscope) which links to something on the inside of the unit...

Would save a jack plug on the case of the unit (i.e simpler production - no holes to drill) and stop the potential for water/dirt contamination through the jack socket hole or its mounting hole.
 
M

manuka

Senior Member
Googling says " Conductors are referred to as inductively coupled when they are configured such that changes in current flow through one wire induces a voltage across the ends of another nearby wire. The two conductors are often physically tightly contained in a single unit, as in the primary and secondary sides of a transformer"

Inductive coupling thus needs AC (or pulsed DC), & the associated coils & DC-AC-DC circuitry may mean wireless serial merits are dubious overall. You'd no doubt have steady DC level issues arising too. This is not to dismiss the approach, but to alert to fish hooks ! Do a Forum search for "wireless programming" etc - I recall Hippy came up with a workaround quite some time back.

THOUGHT: If just dust or water are problems, perhaps consider a more durable 3 terminal protected connector? Even simple screw terminals or flying leads could be used for PICAXE work. As you have to open up the case for battery replacement anyway, just have the socket inside?
 
Last edited:
A

Andrew Cowan

Senior Member
Results for wireless programming:

http://www.picaxeforum.co.uk/showthread.php?t=12249&highlight=wireless+programming
http://www.picaxeforum.co.uk/showthread.php?t=9543&highlight=wireless+programming
http://www.picaxeforum.co.uk/showthread.php?t=6459&highlight=wireless+programming
http://www.picaxeforum.co.uk/showthread.php?t=2887&highlight=wireless+programming
http://www.picaxeforum.co.uk/showthread.php?t=2425&highlight=wireless+programming

Interesting topic - I'll do some more reading tomorrow.

A
 
M

MartinM57

Moderator
manuka said:
Inductive coupling thus needs ... (or pulsed DC)
Click to expand...
Exactly - a bit like a serial data stream ;)

[OutBoxThinking] - RS232->something that generates enough magnetic field to be picked up by a Hall effect sensor inside the box? Would need to cope with bi-directional comms though...hmmm..[/OutBoxThinking]

EDIT: A's first link is one I hadn't seen - the same problem statement! Sort of wanders around the subject with no great conclusion. Maybe a 3.5mm socket on the box with a dust cap (never seen any though) would be easiest
 
Last edited:
L

lanternfish

Senior Member
MartinM57 said:
So being an inductive coupling newbie ... how could I get a serial link working through the side of a plastic case (2mm?). For example, plugging the jack plug end of an AXE027 into something that you then hold against the side of a unit (a bit like a doctor with a stethoscope) which links to something on the inside of the unit...

Would save a jack plug on the case of the unit (i.e simpler production - no holes to drill) and stop the potential for water/dirt contamination through the jack socket hole or its mounting hole.
Click to expand...
You could have 3 conductive pads (rx, tx, gnd) that are glued to the outside of the case. Fine wire run from the pads through the case connect to the internal programming header. A bit of silicon/cold cure RTV should provide adequate sealing.

Of course, the contact metal will determine their longevity. Silver, perhaps?

And make a suitable external adapter from wire and Polymorph?

Or use IR?

But I am getting OT

Cheers
 
M

MartinM57

Moderator
lanternfish said:
You could have 3 conductive pads (rx, tx, gnd) that are glued to the outside of the case..
Click to expand...
I like the thinking but I'm after production quality construction rather than DIY - where the only thing needed on the outside of the case is a silk screen outline of where to touch the <whatever's on the> end of the programming/data lead.
 
D

Dippy

Moderator
Modulation-demod of an AC signal, PCB track loop or spiral.
Or, optical easier; simple LED + photo-tr.
 
L

lanternfish

Senior Member
MartinM57 said:
I like the thinking but I'm after production quality construction rather than DIY - where the only thing needed on the outside of the case is a silk screen outline of where to touch the <whatever's on the> end of the programming/data lead.
Click to expand...
Hmmmm.

Just did a quick Google search and came up with these. Not sure if they are much help as I only skimmed them.

http://www.whoi.edu/home/pdf_files/tivey_ICL_description.3.pdf

http://my.fit.edu/~swood/inductiveData.PDF

This last one looks less 'academic'.

Of course, getting OT as original question was about wireless transmission of power. Oops!
 
Last edited:
M

MartinM57

Moderator
Dippy said:
cal easier; simple LED + photo-tr.
Click to expand...
I remember, an awful long time ago, when there were programs on TV late at night about programming the BBC Micro. They designed an opto-transistor circuit that you could make at home and connect to your BBC Micro. They then 'transmitted' program listings via a small white flashing square in the top corner of the screen, where you blue-tacked your opto-transistor.

Suffice to say, I made one and it actually worked! A bit pedestrian in terms of bit rate IIRC, and you had to stay up late at night to do it 'live' as VCRs and the like hadn't been invented then :D
 
D

Dippy

Moderator
I remember doing a simple data download link; IRLED + Photo-Tr.
Not a lot of data, maybe a dozen bytes, but worked a treat.
Stamp to Stamp and the 'stick it next to it' proximity kept out most ambient light.
2 resistors + 2 semis in total, no modulation, Serout/Serin, couldn't be simpler.
 
D

Dippy

Moderator
Hippy, Martin wants something for production i.e. 'faff free'.

You can get hard plastic or soft rubber blanking plugs in various sizes from Farnell etc.
Will they do for going over a panel hole? (Bit fiddly I admit).

I had a similar environmental issue with a product - which is why I went for optical through a window - the IRLED was on the main PCB in the 'outdoors' box. Worked well, but as i don't know your specifics this is just a thought.
 
F

fritz42_male

Senior Member
Dippy said:
(I saw a TV programme t'other night showing an antenna based 'solar' panel for 'collecting' energy from infra-red. Principle sounds good, but starngely they couldn't demonstrate it.... maybe it suffered the same problem as a Stealth Bomber did at a Farnborough Airshow about 10 years ago.)
Click to expand...
What happened to the stealth bomber?

Incidentally, about 35 years ago I was learning electronics from a local TV repair man who had been a radar operator in the war. The soldiers on the base used to come to him from a blast of radiation in the gonads to prevent them from getting the local girls pregnant. He used to unshield the main emitter (klystron or equiv?) and have them stand in front of it.

Course it wasn't until quite a bit later that they found themselves to be permanently sterile and a few of them went on to develop cancers (or so I was told)
 
F

fritz42_male

Senior Member
MartinM57 said:
I remember, an awful long time ago, when there were programs on TV late at night about programming the BBC Micro. They designed an opto-transistor circuit that you could make at home and connect to your BBC Micro. They then 'transmitted' program listings via a small white flashing square in the top corner of the screen, where you blue-tacked your opto-transistor.

Suffice to say, I made one and it actually worked! A bit pedestrian in terms of bit rate IIRC, and you had to stay up late at night to do it 'live' as VCRs and the like hadn't been invented then :D
Click to expand...

There was also a Timex PDA watch that got synch'd by holding it up to a square on the PC screen.
 
I

inglewoodpete

Senior Member
MartinM57 said:
Anyone seen any 'dust caps' for 3.5mm jack sockets or other enviromentally-protected 3.5mm jack socket connectors?
Click to expand...
Back when we were all a lot younger and used pounds, shillings and pence / feet and inches etc, the humble 3.5mm plug & jack was called a 1/8" plug & jack. I'm sure that the automotive and other industries would have 1/8" rubber or plastic plugs.
 
D

Dippy

Moderator
If you want to reduce the chance of Gunge Ingress then optical/inductive are the way to go. Optical is SSSSSOOOOO easy, but requires a window. Inductive with a tiddly bit of electronics is ideal and a spiral/loop track on a pcb is obv easy.

I'd avoid jacks if poss. Extra hole, poss extra assembly. Depends on the market too. For techy types they might not lose a plug, but if it's for the numpty market then ... well...
 
M

MartinM57

Moderator
Numpty users, main nasties in environment is vibration, then dust, then moisture.

Picking something at (really) random that's absolutely not the actual environemnt then think of something in a case attached to one of those humungous multi-bandsaw machines in a sawmill that takes a tree in at one end and cuts it into multiple 2" slices in one go....

Do you reckon two interwoven 0.5" diameter spirals (one for TX, one for RX) on PCBs separated by 1.5mm of a plastic case would actually transmit/receive anything?

Yeh, I know...I should try it and get the scope out...
 
D

Dippy

Moderator
Now you've got that million pound scope you should be giving it a good thrashing ;)

I'm sure you could, you could even use RF techniques, tags and security bades and all that.
I'd experiment with modulating a frequency related to your coil spec and a simlar receiving coil would have good linkage, resonance and all that jazz. Demod/tone decode and shaping on the Rx.
Are there any hacks you could do with audio induction loop circuits?

PS. Slight Red Herring.
I've never done the above but have used spirals on PCBs for filtering.
Here is a rough calculator:
http://www.deepfriedneon.com/tesla_f_calcspiral.html
(only consider it as a very rough guide though)
 
Last edited:
You must log in or register to reply here.
Top