controling motor

hello guys I have many doubts about motor yet.

My application is... After turn on the motor by button, the motor rolates for example 550 degree, stop and it wait 3 seconds and after return Initiation position.

I have a micro servo of 9g 180 degree

My doubts...
Shoud I control motor per time or degree?
How do I control motor if it is 180 degree?
How can I control the speed motor?
Which would motor be better for this application?

I saw some videos and I modified my motor like - YouTube
but I dont know how I can control my motor yet.

I intend to inform by serial the number about degree or time.
So in this case is necessary to use map?

for example: x = map(x, 0,360, 0,255);
If this necessary ... how would be the instrution map?

I have used some examplos but I didnt get a good result.

I will happy if someone can explain for me.

thanks!

I have a micro servo of 9g 180 degree

This servo can not rotate more than 180 deg. It can be modified for continous rotation, but any position feedback will be lost.

You could get maybe 540 degrees with 1:3 gearing, but it would be a bit sloppy.

For my project, what do you think is better to use?

Should I control motor by time or by degree?
Would the passo motor be a option?

Detail, I need precision.

tks!

professional moving lights (Vari-Lights, Clay Paky, etc) use stepper motors and optical encoders to do exactly what you are trying to do... they go through a homing sequence by moving from one extreme to another (approx 1-1/2 rotations), then go to a very precise position (+- 0.5deg, probably) based on where they are told to go.

the mechanical system to make this precise is steppers, optical encoders, and hard end-stops.

maybe helpful??

Guys thanks for answers.

I m going to study about step motor... how I can choise one for my application

see you