Small turbine for christmas gift?

[strider3700]

For Christmas apparently it's a tradition in my girlfriends family that everyone draws a name and then makes that person a small gift each year.  I've got the brother in law (not that I'm married in but close enough)

 Anyways I was thinking about what to make him and looking at the small solar lanterns I have in my front yard I was wondering if I could build a small wind turbine that will charge a small AA nicad  that at night I could then use a photo sensor to draw the power from the battery to light up a LED or two.  

Now I'm sure this is possible but there are limits.   I not supposed to spend more then $20 cdn and I don't have hundreds of hours of free time. I'm sure I could devote a combined weekend between now and christmas though.

So I went digging through my scrap electronics boxes to see what I had.

It turns out that stripping those old VCR's about 8 years back may pay off,  I found a small 8V motor then when I spun it by hand put out 100 mA at about 3 volts.  A real turbine should spin it much quicker then what I could get by hand.

I also have some old red and green LED's but might splurge and pick up a nice white one if I can't find one.  I'll probably also splurge for the nicad battery.

So My thought is I need to track down a photo sensor to control turning the light on.  I should have a switch somewhere in case they want to turn it off as well.  I have assorted resistors and somewhere I can track down a chart to let me figure out the values off of the stripes.  I need a holder to put the battery in and then I need a case to package it all in and make it look good.   I'll of course also need some blades.

Now I'm pretty sure I can figure out the wiring in the unit.   But I'm not sure how to go about making blades  and what size I should need to pull this off.  Can it be done with a smallish HAWT?  What sort of style should I look for in blades (I wouldn't mind trying my hand at carving  a set of these anyways)  Would a small coffee can sized Savonius produce enough power to light these up?   Should I look at stealing blades off of a fan of some sort?

Thanks for any advice or ideas you guys have

[Jrmobb]

Well first off L.E.Ds need like no power at all so maybe you would not even need a light sensor maybe they could just run all the time and at night you would see them and day time you would not, Just a thought. Only bad thing about fan blades are that they are made to push wind not be pushed by wind, so they dont work that well. I would say either some sort of garden decoration windmill or carve some wood ones.

[ghurd]

Hey!  I just did this about 2 days ago.

The fly heads(?), or angled tape reader(?) do-hickys, I had would not make enough volts to light a green LED, even without any rectifier losses. Green, blue and white LEDs require more volts to light than red and yellow (yellow a tiny bit more V than red) LEDs.  It may have lit up a red or yellow LED, but the circuit boards didn't supply anything but green. lol.

A single Nicd or Nimh will not light a LED. It takes at least 2 for red and yellow, 3 for green, blue or white.

Fan blades are hit and miss. Some 20" box fan blades are pretty OK, but that's all I found that work worth a hoot, and only some of the 20" are OK.

Search here for 'PVC blades' and 'Zub-Woofer blades'.

Also search stories 'screamers' for something by windstuffnow Ed for blades he made from paint stir sticks.

A stepper motor (maybe 5~8V) would light up some LEDs. No battery, no CDS cell, no problem.  

With wind, the LEDs light up. More wind, brighter lights.

Thats more fun than a thing that spins all the time, and something lights up at night.

What I would try for a project like yours...

Search the web for 'stepper motor generators' for wiring one. There are different configurations of stepper motors.

Maybe for a cheap quicky, try NO rectifiers, a red and a yellow LED, parelleled but one backwards from the other (+ to -, anode to cathode), then the pair in series with a 280 ohm resistor. A set of these for each output.

A common $2 or $3, 5 wire stepper needs 4 sets. One for each "output" all connected to the common.

The steppers outputs come out like an 'X', the common goes to the center of the x.

The common wire has the SAME ohms to the other 4 wires.  Output to output has DOUBLE the ohms.

I would make the red LEDs conduct from the common, the yellow LEDs conduct from the outputs.  Not sure how important that is, a power factor / duty cycle kind of idea.

A 6 wire stepper would be wired about the same. Figure out what 3 wires are together.  2 pairs of LEDs and a resistor from the output to the common.  The same for the other 3 stepper wires.

Large diameter blades won't spin fast enough for good operation.

Try 16" diameter Zub-Woffer blades first Don't bother with 16"dia fan blades, unless you have them all ready. Don't change their angles, regardless of the diameter, tip is tip, root is root, angles. (been there, done that. Changing angles won't help. LOL.)

Most square steppers (stacked steel plates) have bearings. Most round steppers (tuna can) have bushings. Bearings are better

Try to use 10mm Diffused LEDs. Same power, but they look more impressive for something like this.

G-

[jlt]

you might try a timer moter out of a washing machine i have one that will light up a red led. And you can get one for nothing. A small 8in fan bladeoff of a bath room fan will be enough to spin it .i can get over 12volts out of mine but only abouy 30 milliamps. will not blow out my red led lamp out. but it gets very bright in a strong wind.you might try robbing the sircut ouy of a solar light. for the photocell.you will also have to put in a rectfier as the timer moter puts out ac  

[Norm]

   Try something like this ...maybe a little

stronger material...aluminum flashing or some

aluminum siding fastened together with little

1/8 inch bolts...





   They're spaced about 60 degrees from each other.

   Hook it up to a stepper motor.....or even go

to http://www.picoturbine.com/

 and build an altenator similar to

theirs.

                 Should be a fun project!

                     ( :>) Norm

[hiker]

this works-small motor two coils two harddrive mags....

and a bunch of l.e.ds. on those little arms sticking out..

looks kinda cool at night--the l.e.ds blink on and off when fired up by the coils..

[richhagen]

I've made small one foot blades that would do the trick for lighting a few leds.  You can make some out of 1-by scrap, a coping saw, and a wood file and sand paper.  A scaled down version of Hugh's or DanB's blades would work fine.  As for a generator, a small stepper would work well as it has no brushes.  One with bearings should last a long time I would think.  I had a contraption up lighting some LED's in my basement for a while which was made this way, except that I made the blades on a small CNC machine.  The post for that little project is here:

http://www.fieldlines.com/story/2005/4/8/31534/30936

Something similar would probably work well for your project.  The blades would probably be fun to make, but if you have difficulty and need a set like the ones I made, write me as I have a few sets lying around at the moment.  They won't make a lot of power, but for a few LED's should work fine, especially if you are building a circuit to charge one or two ni-cads and discharge them into the leds only at night.  I have yet to do that with a mill, but I rebuilt one of those little solar lights.  I used a low power op amp as a comparator I think it was a TLC271 or something similar by the number, with a voltage divider with one leg as a cadmiumsulfide variable resistor for one side, and a voltage divider from the battery as the other side.  Used large value resistance, and it works well to this day.  I replaced the batteries in that one with about 22 or so 1 farad 5.5V memory capacitors protected by 5.1V zeners as a shunt controller.  It sounds like a fun project.  Rich Hagen

[Bruce S]

Norm;

   Nice cute little unit. And here I am still trying to gather up enough coffee cans!

A word of caution , don't bother with the Pico turbine. The kits sent out now are using alumminum wire and it breaks a part way too easy and no refunds.

I have the Pico and the kit (for what I paid, was disappointing) It took me a lot of extra doing to get it to be a descent setup , and this was supposed to be for a scinece learning project for our daughter. Only good thing about it was the pre-coiled wire that works really good with HD magnets.

Go with -Eds kit costs less and looks like it will be a better product. I plan on ordering one if he still has them available, and I find the coins.

Bruce S