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Electric Flag.

Posted: Jan 07 2019 10:05pm
by APL
I'm in one of those crazy moods tonight,..probably regret this later... :oops:

A while back I had the Idea of making an electric flag, that would run some kind of generator, piezo, or shaker flashlight
type of system, mounted somewhere towards the front, that runs off the back and forth motion created by the wind.

I know it's fairly pathetic to look at at the moment, but all things start somewhere. (the only photo I could find)

11 2014 bug+ 109.jpg
11 2014 bug+ 109.jpg (116.7 KiB) Viewed 467 times

I started the experiment with some foam board and duct tape,..trying various lengths of panels. Depending on the
length's, you can vary the frequency of 'the shake'.

Then I started attaching weights to it, to see how much power was available. that's about as far as I got on the deal.
It does work quite well though.

The thought was that it could be made simple, light, and could charge phones or lap tops at camp sites, or remote areas.

They can be made quite large, or used in great numbers, and are a great place to put advertising.

Even if the sun don't shine,(night), there is almost always wind, and they can be left to run for months, or years.

I thought I'd put it here in case anybody wants to experiment with the idea, it's a tinkerers delight! :D

Now give me three steps for the door....

Re: Electric Flag.

Posted: Jan 07 2019 10:43pm
by amberwolf
Interesting idea; would fit where props/etc wouldn't, I suppose.

There are some articles about similar things out there, if they help: ... ing%20flag

Re: Electric Flag.

Posted: Jan 08 2019 10:51am
by craneplaneguy
One long term problem would be, just like with wind turbines: build it sensitive/large enough to work in light winds (which is the majority of times), and the first storm that comes through will tear it apart. But, also like with wind turbines, that problem could be solved.

I think I remember reading about some outdoor clothing that operated on a similar principal, a hiker's movement produced enough current to keep a phone charged, something like that. It may have been for military applications.......

Re: Electric Flag.

Posted: Jan 08 2019 12:54pm
by APL
I had to laugh when you mentioned storms tearing it apart! Thats exactly what happened to the last 'windmill' I made. :lol:

"The wind is like Loki, god of mischief, and always finds a way to dash your foolish efforts."

It's a fun thing to play with though, and a good way to get the kids involved in science and wind power. I actually found
myself hoping for windy days! :)

Another thing that it can be used for, is moving, or pumping water. If small tubes with check valves were installed, the
flapping action would pump fluids through, for a well, or holding tank, or hydro generator? Just a thought.

Anyway, If your building one, the fist panel is the longest, and is attached to a piece of tubing, so that it can turn.
The second panel a little shorter, and the third,..perhaps shorter still. The tape between the panels is the 'hing',
and should be loose. It needs three panels to work.
Photo is the first one, and needed improvement.

Re: Electric Flag.

Posted: Jan 08 2019 1:20pm
by billvon
Could be a fun idea, but you'll probably only get a few milliwatts, so no charging of cellphones or laptops. But it would likely be enough to power a small weather station or something that transmitted intermittently.

Re: Electric Flag.

Posted: Jan 08 2019 3:57pm
by fechter
A few years ago somebody was looking at making a "tree generator" by tying a rope onto a large branch high up in a tree and using the back and forth action from the wind to power a generator. This could be very portable (except for the tree).

If the rope was wound around a drum, you could use either a big spring or a container of water or rocks as a counter weight to make the drum spin back and forth. If the generator resembles a used bike hub motor, then you can generate power in both directions by hooking the phase wires to a bridge rectifier.

The flag could work in a similar manner but would need to be pretty stiff.

Re: Electric Flag.

Posted: Jan 08 2019 6:45pm
by APL
A few milliwatts? Your probably right. Fact is, the wind usually blows around 10 mph or so, and theres not a lot of action.
It needs to get up to 12-15 mph to be useful at all. Still, it's cumulative,.. all day and all night.

Depends on the State, and the hight, I suppose. People all over the world,..some places are windy. Up north, in the arctic,
or out in the desert, might be more useful. If you live on the coast, you probably have it made,.. lots of wind.

I was going to wind coils around tubes,(3-4" long), and put a neo in them, with springs on each side, so they could bounce
back and forth. Hooked up to a bridge rectifier, like fechter said. Perhaps charge a large capacitor? I haven't really thought
it out that far.

Several of them could be mounted in front. I tried attaching weights on one to see how much it could take, and I think it
would handle 2 to 5lbs, depending on the wind, for a small one,..if I recall.
I'm not sure how big one could be made,..perhaps 8 foot?
A person could run dozens of them too.

Well, I guess I just don't know,.. I wish I had more time to fool with stuff, but I'm knee deep right now,.. maybe later.. :)

Re: Electric Flag.

Posted: Jan 09 2019 12:23am
by fechter
It might work better if the hinges were horizontal instead of vertical. That way gravity would pull it down and the wind would lift it up. Sort of like a wind sock.

It's hard to generate with magnets that are moving slowly. Some kind of gearing or linkage that speeds up the magnets (or coils) will be much more effective.

Re: Electric Flag.

Posted: Jan 09 2019 12:08pm
by billvon
APL wrote:
Jan 08 2019 6:45pm
A few milliwatts? Your probably right. Fact is, the wind usually blows around 10 mph or so, and theres not a lot of action.
It needs to get up to 12-15 mph to be useful at all. Still, it's cumulative,.. all day and all night.
You get 12-15mph all day and night? Wow. Around here we get that _maybe_ once during the day and then it calms down at night. You might be in a good location for a real wind turbine in that case.

Re: Electric Flag.

Posted: Jan 09 2019 2:25pm
by APL
12-15mph a few times a week,'maybe'. Funny thing about the wind,..when I ride my bike, or go fishing, I always wish
for no wind, but when I fool around with these things, I wish for high wind,..go figure.

I've seen windmills that use horizontal flaps, and your right using gravity is a good idea. I had thought about getting
magnet speed up by using an offset weight on a shaft that spins, but it wouldn't take much drag to stop it. Perhaps a
shaft going down into the base, with a double ratchet?

Here's an intriguing idea, a 'ribbon' windmill, that works off the high frequency tension. Can be made much bigger, or
in great numbers? Hmmm.

Ribon generator.jpg
Ribon generator.jpg (30.03 KiB) Viewed 353 times

Hey,..don't kill the flag!! :)

Re: Electric Flag.

Posted: Jan 16 2019 6:12pm
by APL
An even better idea, is to make one of these wind sculpture machines into a generator. Best of both worlds.
Good look's, and useful function. Not easy though.

Worth watching.

Kinetic wind sculpture..jpg
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