Need help with Stepper design

I’m as newbie as it gets and I have an off the wall project that likeley requires the use of some robotic engineering to make it work right. I am trying to figure out what I need to turn a 5-350pf variable vacuum capacitor. I believe I want a stepper motor and some sort of pulley belt attached to the post of the variable cap but not sure.

The object is to have the capacitor tune up and down but I need limits; I assume I will have to count the rotations manually and then set the stepper controller/driver limits so the capacitor does not bottom out or unscrew from the shaft all together. Id ultimately like to program it so it could automatically work with a set of buttons (one for up & one for down)

Now that you have an idea of what I am looking for; I am asking for help on what stepper motor, controller/driver to buy. I’d like this to be tetherless, i.e. not having to be connected to the computer to be able to work, perhaps program once on computer and save to board. Id also like to get some sort of display either analog or digital that will tell me the relative location of where the capacitor is at. I can sketch up my conept and email or post it if you are interested in helping me out.

Thanks in advance for your help and considerations

Hi w6drg,

Welcome to the RobotShop Forum. A sketch would indeed help. You can post it here. You will need to get an idea of the torque required to move the object up and down. If you do not have any measurement tools, try to ad-lib, just to get a sense of the torque required by the motor (torque = force x distance). Also, you indicate you would like the system to be wireless, but do you need it to be computer controlled? As much information as you can provide would be appreciated.

Sincerely,