NEED HELP STUCK!!!!!

I have to turn the dome of my windmill according to the direction of wind for which i need some motor mechanism can you please tell me which motor to use for this task ..............

No motor at all. Us the prinsiple of a weather vane. Let the wind do the turning.

I am using a weather vane to detect the change in wind's direction but now with the help of this detected direction I want to turn the dome of windmill via arduino.....

eurodo061: I have to turn the dome of my windmill according to the direction of wind for which i need some motor mechanism can you please tell me which motor to use for this task ..............

What is the mass of the dome your trying to turn as this will greatly effect the choice of parts.

tell me which motor to use for this task .

Because you've told us nothing about your device, the only answer can be "the right one"

It is just a prototype of around 200 grams and also it should be able to rotate 360 degree freely

Because you've told us nothing about your device, the only answer can be "the right one"

Here is some information about what I am upto I am making a smart windmill system in which the windmilll is able to adjust itself according to the direction in which wind is blowing in order to make the traditional windmill system more efficient so i have created a wind direction detection mechanism now I want to turn the dome of my windmill according to this detected direction with the help of some motor mechanism so I need help with that...................

Based on the information you've given us, I'd suggest one that can rotate 360 degrees and is controlled with electricity that is then sized properly for your project. You can probably use a DC motor with an encoder, a stepper motor or a free rotating servo (I think I'm naming this wrong).

Anywho, think very carefully about what you think we should know about your project to help you find a motor. KNowing that it is a wind thing doesn't actually help us beyond the 360 degree part.

If you attach the wind direction sensor to the dome, you can implement this using a very simple system where the dome is moved until the dome is aligned with the wind direction sensor. This avoids needing any absolute position sensing for the dome, which means you can move it with any simple motor/gearbox drive system. For example you could mount the dome on three wheels on radial axles around the pivoting axis and have one of the wheels driven.