I’m working on a modeling project and am trying to motorized the rotation of a gun turret. I’d like to be able to limit the amount of rotation to between 180 and 270 degrees with a rotational speed of around 18 deg/sec. controlled by an Arduino. I’ve been looking at different motors and servos but am coming up blank and was wondering if anyone here might have some advice.
I don't know if you need it accurately exactly 18 deg/sec, but the Tower Pro 9G micro servo is normally good for projects. It is very cheap and has a limited amount of rotation (as all servos do) and is easy to program with the Arduino Servo library (built-in). It comes with a few different blades and screws easy to mount on your device. Just google Tower pro 9g micro servo motor
What are the size constraints? How much torque do you need? How will the motor be powered?
You can slow the rotation of a servo by moving it a small amount at a time with delay between movements. See the VarSpeedServo library.
There are very small stepper motors. They do, however, take more parts to control than a servo.
The VarSpeedServo library will help sort out the speed. Other than that 180 degrees is easy to achieve, many hobby servos can do that. Much more than that is trickier. There are a few servos that can manage 270 degrees but not many.
Don't get tricked into believing that what you want is a 360 degree servo...the things called that are no longer real servos with positional control but instead are continuous rotation "servos". The only control you have is over direction and speed of movement NOT position.
People have made model railroad turntables with Arduino control. There might be something in that area that could be applied.
Seirsan, there are several videos that address the very thing you are asking on YouTube. Look up this guy ' revwarguy7' or search 'stepindex'.
It has to do with using a motor like they use on CNC machines. They turn using pulses, and you can adjust the amount of steps it uses to turn. In doing so, you can cause it to turn faster or slower.
An UNO, keypad, motor driver and a motor (like a nema17), is a list of parts you'd need. Well under $50 for all.