Making servo spin and able to detect angle

Question

After researching other posts I can see how to make a servo spin continually and remove the ability to set to a specific angle.

What I'm trying to do is make a small project that has a spinning 'game wheel', each segment of the wheel has a prize on it (think almost wheel of fortune). The catch is when someone has landed on a prize once it cannot be landed on again so I want to manipulate the spin slightly so it doesn't stop on the same prize. Do do this I need to be able to get the spin AND know where the needle is pointing.

Is there a component that will allow both a full rotation AND the ability to control the location of the needle at the same time? I suspect servos can do one, or the either but not both.

• BrettFolkins: I think you should look into stepper motors
• Gerben: Look into 'optical encoders'

Answer 1

The way I'd do it is the following:

• use an optical encoder with an endstop, they come @ 1€ on ebay, bought 4 today :-) - this will tell you the angular speed and incremental position
• use a photo transistor to detect a specific point on the wheel (make a small hole or paint a spot in a different colour) - this will give you the absolute position of the wheel, to calibrate the previous step.

With this solution you do not even need a step motor, a DC motor will do it and probably has better characteristics, for the same cost. So you could explore the DC option if it turns out that the stepper is not good enough.

Answer 2

As for Me the Best Way to To Use a Position Servo with the Feedback in it ( it comes with 6 wire ) then You put all Your Positions For the prizes in An Array and if Anytime You Land on An Index then You Should but it in an Array that Holds all the prizes angle visited Which you will use as a check Before Turning the Servo

• James Waldby - jwpat7: Darkclaude X, please edit your question to get rid of all those capitalization errors.