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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!
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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Signing UpStep 1Materials and tools
For the turbine and tail vane:
1 piece of 2mm thick balsa 10 cm by 40 cm or 4 pieces 10 cm by 10 cm
4 bamboo (meat) skewers 30 cm long, about 3mm diameter
some cellotape, at least 19mm wide
superglue
large gear (about 60 mm diameter, Opitec part 840088)
a piece of scrap wood, 3 cm thick and about 6 cm by 6cm in size.
some non-stick paper,
1 small stick of hotmelt glue (low temp type when working with kids)
a cabinet screw with an unthreaded part, fitting loosely the gear hole (4mm for the gear mentioned above), about 35 mm long. A brass screw will last longer in humid conditions, I found out screws with a nominal diameter equal to the gear hole, actually fit loosely.
4 washers fitting the screw
paint and varnish (optional)
For the generator:
a “solar grade” toy motor with 7cm leads (FF 130 “solar motor”, Opitec part 224176 works great, but needs leads to be soldered to the motor. The RF 300, Opitec 224154, comes with leads, but is less resistant to rain)
a small pinion gear of the same module as the large gear (Opitec 841187 with adapter 842022)
a (steel spring) clamp fitting the motor/generator (Opitec 225074)
a 25 mm long bolt and nut. I choose M3, allowing for all drilling to be done with a 3 mm bit.
For the Joule Thief:
a ferrite toroid (e.g. Conrad 507997 or 508039)
a 2N3904, BC 337 or equivalent transistor
a 1kOhm resistor
1 to 3 LEDs (the clear ones are easiest to see lighting up in sunlight)
2 times 20 cm of insulated thin gauge electrical wire (twisted strands from telephone or network cable are perfect)
5 small cabinet screws, preferably brass (more durable contact). I choose shortest 3 mm diameter ones I found, allowing for all drilling to be done with a 3 mm bit.
For the mast
a 27 cm piece of 20mm diameter PVC electrical tube
a 75 cm to 1 m long piece of 16 mm PVC electrical tube
2 tie-wraps (pretty small ones are OK)
a marble
Tools:
a junior hacksaw
a flat working surface (theoretically 31 by 31 cm, but take double to work with some comfort)
a hotmelt gun (low temp type when working with kids)
a drill (preferably column-type) and a 3mm drill bit
screwdrivers fitting the screws and bolts used
some templates can be made out of scrap wood as explained in the following steps
1 piece of 2mm thick balsa 10 cm by 40 cm or 4 pieces 10 cm by 10 cm
4 bamboo (meat) skewers 30 cm long, about 3mm diameter
some cellotape, at least 19mm wide
superglue
large gear (about 60 mm diameter, Opitec part 840088)
a piece of scrap wood, 3 cm thick and about 6 cm by 6cm in size.
some non-stick paper,
1 small stick of hotmelt glue (low temp type when working with kids)
a cabinet screw with an unthreaded part, fitting loosely the gear hole (4mm for the gear mentioned above), about 35 mm long. A brass screw will last longer in humid conditions, I found out screws with a nominal diameter equal to the gear hole, actually fit loosely.
4 washers fitting the screw
paint and varnish (optional)
For the generator:
a “solar grade” toy motor with 7cm leads (FF 130 “solar motor”, Opitec part 224176 works great, but needs leads to be soldered to the motor. The RF 300, Opitec 224154, comes with leads, but is less resistant to rain)
a small pinion gear of the same module as the large gear (Opitec 841187 with adapter 842022)
a (steel spring) clamp fitting the motor/generator (Opitec 225074)
a 25 mm long bolt and nut. I choose M3, allowing for all drilling to be done with a 3 mm bit.
For the Joule Thief:
a ferrite toroid (e.g. Conrad 507997 or 508039)
a 2N3904, BC 337 or equivalent transistor
a 1kOhm resistor
1 to 3 LEDs (the clear ones are easiest to see lighting up in sunlight)
2 times 20 cm of insulated thin gauge electrical wire (twisted strands from telephone or network cable are perfect)
5 small cabinet screws, preferably brass (more durable contact). I choose shortest 3 mm diameter ones I found, allowing for all drilling to be done with a 3 mm bit.
For the mast
a 27 cm piece of 20mm diameter PVC electrical tube
a 75 cm to 1 m long piece of 16 mm PVC electrical tube
2 tie-wraps (pretty small ones are OK)
a marble
Tools:
a junior hacksaw
a flat working surface (theoretically 31 by 31 cm, but take double to work with some comfort)
a hotmelt gun (low temp type when working with kids)
a drill (preferably column-type) and a 3mm drill bit
screwdrivers fitting the screws and bolts used
some templates can be made out of scrap wood as explained in the following steps
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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.
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!
Many thanks.
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!
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.
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.
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!
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.
Takes a while for shipping though, as all the cheap ones ship from China.
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.