Constructing of all these things is indeed quite simple, and you need to keep it simple to succeed. Often enthusiasts make the mistake of reaching out too high and find themselves fighting with technology which is too complex, expensive and unfamiliar to them. Thunder, wind, rain and constant rotation make special requirements for complex mechanisms and microelectronics to manage in the long run. For this reason it is more feasible to seek for more robust solutions. In my experience, automatically adjustable blades are too complex solutions for private people to succeed in. These wind mills contain no special parts which are difficult to find, nor other expensive elements you need to buy by cash. All other parts except standard aluminium plate for the wings, the belts for gearing, plywood for tail, bulbs, paint and cement are recycled material and can be found after some seeking from any junk store at the price of the scrap metal.
Even many strategic parts are recycled material, like bearings, large size bolts, electronic transformers. The actual assembly, is however, tailor made for this wind mill purpose. The basis of design has not been the gathered parts, but rather the vision of making this kind of wind mill. Both wooden pole and lattice tower (I happened to find a 25 m high lattice tower) can be used to hoist the mill into the wind. The electronic transformers are old computer power supplies, which are available from junked computers free of charge. They provide 12 V (11,7V) up to 12 A each from varying quality alternating current and can be used as power supply for floodlights.
Always prefer AC generator to a DC one. It is much easier to manage with alternating current, and if needed, it can be directed to DC. Brushless AC generators are very long lasting, as the only wearable parts are the bearings.
Wind mills are exciting in that, they ask little after they have been erected. The power out put is, however, very fluctuating. Even at windy weather power out put drops close to zero from time to time. Opposite to solar systems, windmill provides energy around the year in Finland.
Please, do not hesitate to take contact in case you are interested to built your own wind mill according to my experiences.
This sun mirror was completed in 1984. Concave mirror surface consist of over one thousand small mirrors, which make total 12 m2. Mirror collects solar radiation to one point, from where it is lead into the house heating system by circulated liquid. Heat out put of the system is 6 kW, but the weakness is that sun has to shine from clear sky. On the other hand, the system works well also in freezing weather. Light sensors guide the system to turn the mirror to the direction of sun.
