I am building a moving target for my kids slingshot… it is a simple design, a post a spinning arm that moves fairly slow and potentially stops at certain positions. It never goes a complete 360, it hit 6 on a clock goes the other way…
I am trying to figure out what motor is best to use with the Arduino controlling it.
Motors are not my skill set at all.
Just excited the sun wants to work on the project with me.. he is 9
Bar with target weighs about 20lbs. Looking at 2-10RPM and stopping at 8,9,10,12,2,3,4 on clock
Most servos made for hobby use turn only 180 degrees (if that).
Stepper motors are made for precise positioning. They could do what you want. There would need to be at least one position sensor so the motor can "home" on start up.
You could use a regular gear motor with sensors at each stopping point.
Is the arm rotating about a horizontal axis? If so, you could add a counter-balancing weight. This would reduce the torque needed. You will still need torque to start and stop the motion, but less than before. Especially since your rotational speed is pretty low.
The size of the motor would also depend on how you support the shaft carrying the arm: plain bearings would need more power but be less complicated than using say ball bearings.