Disclaimer: This windmill generator will not facilitate off grid living. Tests show that it's about as powerful as 1 x AA battery (since completion there hasn't been a breath of wind to test it properly).

Double Disclaimer: I work in the financial services industry so have no formal knowledge/learning with regard to anything in this tutorial, everything I know I learned from YouTube.

This was a 'father son' / 'COVID-19 lockdown' / 'home schooling' project covering building stuff, windmills (it's my son's school logo) and sustainable energy.

Supplies

Scraps and things I had laying around (the only purchase was the lazy Susan bearing which cost ~£4):

Wood off-cuts of various sizes
1 x 12mm threaded bar
2 x M12 nuts
2 x Locking washers
Dowel
Old cordless drill
Corrugated plastic sheeting
2 x Pillow block bearings
1 x T Nuts
Wooden cable drum
Lazy Susan bearing
2 x Overlap cladding panels
Cable ties
Roof felt
Screws of various sizes
OSB board

Step 1: Constructing the Blades

Squared off a bit of 2" by 3"
Drilled 15mm holes through the center for the axle and 2 more holes on each side, off set so that the sales would be at an angle in order to catch the wind
Threaded the axle and secured with a T nut and locking nuts
Dismantled an old baby gate in order to salvage the dowel
Glued a dowel into each hole
It was way to big so we had to shorten each blade by half and fix a bit of wood at each end to secure in place

Step 2: Adding the Sales

I had a sheet of corrugated plastic that some roofing sheets came packaged in which we marked out some oblongs that would wrap around each blade
We cut out the 4 oblongs
We drilled some holes that will be used to tie the sales to the blades
Bent each one around and secured with small cable ties

Step 3: Creating the Body

I had an old wooden cable drum sitting around which I squared off for the base
We drilled a 20mm hole in an off-cut of 2" by 4" and affixed a pillow block bearing each side to allow the axle to spin freely
This was the fixed securely to some OSB board
I'd ordered a bearing for a lazy Susan (my only purchase for this project) and used it to join the base to the axle holder, this would allow the top section with the sales to rotate in order to catch the wind as it changes direction
We threaded the axle and then using an angle grinder smoothed the end of it off so that it would fit to the "generator"
Using some old over lap cladding we clad the base (for aesthetics and weather proofing)

Step 4: Adding the Roof

With various off-cuts we fashioned a roof that would keep rain off the "generator"
Then we covered with a bit of old roofing felt for additional resistance to the elements

Step 5: The Generator

A generator (in it's simplest form) can be created by energy being passed through a DC motor in the opposite direction.
We took and old cordless drill apart and salvaged the motor
By switching the wires from the positive and negative terminals around it put the motor in reverse it would allow a clockwise rotation to generate a positive current
A very rudimentary supporting block was fashioned to hold the motor in place, fixed to the base and the chuck tightened onto the axle.
The motor was then cable tied to supporting block (using a bit of bubble wrap for cushioning)
With the drill motor set to the least resistance (to allow the sails to rotate more freely) a test of us spinning the blades gave us an output of 1.52 volts... SUCCESS!

Step 6: Ready for Testing

I creosoted the structure as this will be living outside in the garden.

Once we have windy day we will test this in anger. By switching the drill motor to a setting with greater resistance we will be able to generate more voltage however there is a chance that the resistance will be to great and the sails may not turn.

Watch this space for a video of the first test...