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Mass producing LED powering wind turbines in a kids workshop

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The Junior Wind Turbine project.
                                                                                                                                              
For my latest workshop in my daughter’s school I wanted to let the children each make a wind turbine. It wanted it to be functional, powering a small light and it needed to be cheaper than 6 Euro a piece, which ruled out any commercial kits.

The workshop was for 20 kids, which ruled out scavenging hard discs motors or stepper motors and such. Low cost “toy” motors on the other hand need really high rpm to light up a small bulb or a led. Fortunately the type of motors used in solar cell driven toys and kits work better. And these are still available for under 2 Euro.

A small flashlight bulb was actually easier to get to glow than lighting a LED, when driving a 6 to 1 gear on a “solar grade” motor by hand. But it required too much torque for a small and simple wind turbine.

A LED worked with a turbine and a single step 6 to 1 gearing, but only at really high wind speeds, needed to get a high enough voltage. But I wanted the kids see it functioning, without having to wait for a strong wind. To apply a higher gear ratio in one step needed a larger gear wheel which I could not find at a low price. A two step gearing gives to much friction with the cheap and simple construction techniques suitable for a kids workshop (remember we are talking about gearing up, which is more critical to build quality).

But our good friend the Joule Thief came to the rescue. With this little circuit added, the LED lights up at a breeze. Moving the wind turbine by hand easily lights up the LED. I estimate it starts at wind speeds below 10km/h. And everything still holds up at strong winds.

Apart from attaching leads to the motor/generator in advance (“solar” motors are often sold with leads anyway) the circuit is built up without soldering, as I prefer to avoid that when working with 20 kids aged 6 to 12.

All that was left was making some “templates” for the steps that need accuracy and gathering the materials and I was ready for the workshop. Check the result in the video below and read how we built the wind turbines in this Instructable.

My special thanks goes to Emma, for her assistance when taking extra pictures showing the detailed construction steps.

Thanks for the votes for this entrie in the MakerBot Challenge!

 
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Ugifer3 years ago
These are really lovely.

I'm wondering whether I can do this with an after-school club that my daughter attends. They are quite young (5-11) so I might need to do most of the cutting and drilling but they could do the assembly.... humm I think we might be able to do it, even if we split it over more than one session.

Lovely instructable and a really great project. Thanks.
masynmachien (author)  Ugifer3 years ago
Thanks you very much.

It should work for that age group with some preparing and enough adults to help. I did this with a group of 20 children, aged 6 to 12. We were 5 adults (4 of them unprepared) to help them. We did in 3 hours.

Drilling is something kids can do from a very young age, using a drill press, some template or some foolproof clamping for the work piece, and of course under close supervision. And they absolutely love it. As I only have one drill press, it is a bit of bottle neck, but in the meanwhile they can decorate or do other things.

Sawing is a bit harder, but most will manage with the simple templates I prepare made from hard wood with a cut and some bits nailed on it to position the workpiece. Some spare wood to redo a piece once in a while, has proven to very useful.

Actually what did prove hard in this project, was inserting the screws when more than two wires where inserted in a hole. The simple solution was to enlarge these holes wit an awl, before inserting anything. Drilling these holes (but only these) 0,5 mm larger would work to, but it requires a second passing at the drill press.

I cut the balsa squares, plastic tubes and the wires in advance. Given time and help, the kids could do it themselves, but they would have to take turns cutting it from the larger pieces. So It saves a lot of time time and eases handing out the materials.

If you have any questions left, please feel free to ask.

I wish you a lot of success with your ow version!
Thanks for your help - I think I might try a small group first time and see how we go. Am currently trying to source the materials and oddly, 16mm PVC pipe is proving the hardest to find. Any hints on where? 20mm seems to be everywhere but I can't find 16!

Many thanks.
astral_mage Ugifer11 months ago
try mc mastercarr. com they should have every thing u'ill need
masynmachien (author)  Ugifer3 years ago
It's reasonably common here. But you can use any stick about that diameter. A tube's open end keeps the marble in place wen assembling, but a solid rod will work fine.
Yeah - that was my backup plan - use a piece of dowel and mybe pout a counter-sink hole in the top to keep the marble in place. Plastic is more weatherproof thou' so I thought it was worth asking in case you had a mystery source!

I might see if I can get some reasonbly straight banboo of the right diameter - that would be more weatherproof than dowel (&cheaper) and is pre-bored!
masynmachien (author)  Ugifer3 years ago
Bamboo sounds like a great idea. If you increase the overlapping length of the 20 mm outer tube, the diameter of the inner tube, rod or dowel becomes even less critical. Obviously it has to fit with some room to move freely, but even if it is a lot thinner, the turbine will remain reasonably upright when the overlap is long enough. Of course the inner tube or rod should not bend to much in the wind. But that should not be a problem with bamboo.
Just thought I'd let you know that yesterday I did a project day with a half-dozen six year olds based very closely on these wind-turbines.

I set up the (hand) mitre-saw with a guide so that they could do the sawing, and we used a drill-stand with a template much like yours for the generator and rotor holes.

For the wiring holes, I made little stickers with five different coloured dots (~4-5mm) on them. They stuck the stickers to the top of the mast pipe and then drilled through each spot. That gave the holes in acceptable positions and meant that the wiring could be along the lines of "orange motor wire into the orange hole" etc. I found that very small stainless woodscrews were better than brass because they are much more pointed and so easier to get started in the hole. Contact with copper wire may make them rust but it will take a while.

So thanks for posting the instructable. I had some very chuffed little girls and some amazed mums by the time they were picked up at the end of the day.
masynmachien (author)  Ugifer2 years ago
Wonderful!

And the stickers sound like a great idea.

I guess nor the stainless screws nor the wire will corrode that fast. In theory combining two different metals leads to corrosion of the least nobel one. Actually, well passivated stainless steel acts quite inert, so in some conditions it may be that the copper corrodes. But in practice, I expect you will not have corrosion problems within the lifetime of these wind turbines.

Thanks for sharing.
Ugifer Ugifer2 years ago
PS we used 50cm lengths of pipe over 120cm bamboo canes with your marble bearing and they turn fine in the wind.
Oh - and I meant to say - thanks for your reply!.
abhishek1232 years ago
great instructable can u pls tell me the rates voltage and rpm of ur motor
masynmachien (author)  abhishek1232 years ago
Thanks,

You can find specs on the motors at the site of Opitec, were I sourced them from.

I did not measure the rpm or voltage we obtained with the turbine.

If you like this kind of projects, also check out this Ible where I used a stepper motor from a discarded printer.
thank u so much for the link ur projects are reallyu miraculous !!
Ugifer3 years ago
This is such a fabulous wiring solution!

I sometimes do some sciency things with a little after-school club that my daughter attends. Hopefully we can do these generators but either way, I am completely stealing this wiring method!
masynmachien (author)  Ugifer3 years ago
Thanks, that is what sharing Instructables is for :-)
fneets3 years ago
i didt made the whole thing but i just found a permanent motor and a generator..
TheHebe3 years ago
You've put a few adults to shame! Kudos kids!
Awesome! I'm going to have to try this with my science club!
masynmachien (author)  JoshuaZimmerman3 years ago
Thanks. Please keep informed on the result.
Now I just need to find a source of cheap gears...
masynmachien (author)  JoshuaZimmerman3 years ago
In the States I guess www.kelvin.com is the classic source.
Brilliant! If you don't want to make the joule thief circuit, you can buy emergency mobile phone chargers from ebay from around £1.50 each, they are just a joule thief with a battery holder. That might make it even simpler and easier.
masynmachien (author)  scraptopower3 years ago
Thanks.

Very interesting tip! I have been scavenging Joule Thief circuits from cheap solar garden lights, but unless one has a good use for the solar cell, that is not the cheapest solution.

Of course, making the Joule Thief is fun in itself, but depending on the group or the project it could be very welcome to simplify things.
I used them on my thermoelectric generator, they're good and cheap. Here's one in for $1.37 : http://cgi.ebay.com/Emergency-Battery-Charger-Nokia-SAMSUNG-phone-Mp3-/250643464754?pt=PDA_Accessories&hash=item3a5b83c232

Takes a while for shipping though, as all the cheap ones ship from China.
Ronak3603 years ago
cool but bit unstable
masynmachien (author)  Ronak3603 years ago
Thanks.

The wind was very unstable the day of filming, and of course the simple and light construction is indeed very sensitive to any changes in the wind. Actually, the kids like that.
Wow that's amazing.
Thanks