# Rotating Wheel ... Sensing the degree of rotation of the whee?

Hi everyone!

I'm about to start my first arduino project, and I need a lot of help in terms of how to get started to make my project function.

For what I'm doing, I'm making a table-sized round surface that spins with a single ball attached attached to an edge of the circle. It is similar to a game wheel.

Depending on the rotation of the wheel, a video projection will change in speed. So, for example, if the wheel is at 0 degrees, the video projection will be at 0:00. When the wheel is at 180 degrees, the video will be halfway played through. When it rotates back, the video plays backward following exactly to the wheel.

I will be using arduino for this project. Any ideas if there is some form of sensor to help me build this setup?

There are sensors which could detect the rotation of the table yes. But, first things first, how do you plan to control the video playback?

The plan is to use Processing and Madmapper to control the projection in relation to the rotation of the wheel.

Use a shaft encoder to measure the rotation angle.

Feifei:
The plan is to use Processing and Madmapper to control the projection in relation to the rotation of the wheel.

OK, I don't know anything about that, but I was worried that you thought the Arduino could handle the video. We often get newbies here who think things like that.

what level of accuracy or resolution do you need? How small an angle do you need to be able to measure? Think carefully about that because the smaller that angle, the more difficult the project becomes.

As jremington suggests, a shaft encoder is one method. It would be relatively easy, but it might not give enough resolution and it won't give you absolute position.

A simple potentiometer would be easy, but would not quite have full 360 degrees of rotation.

Another way is to make a quadrature encoder. This will give you as much resolution as you want and give you absolute position, but it will not be easy to make.

What size, weight and material will the wheel be made from, approximately?

Will the wheel be able to rotate freely through/past the 0/360 point or will there be "end stops"?