I’m converting a Bruder Toy Excavator into a RC and need some advise on how to control a Hacked servo that has been modified to rotate continuous in either direction. My plan is to connect a wood drill bit to the servo which would rotate the bit and drive two set screws on a shaft that slides over the bit. By rotating the bit with the servo it would extend the length or act as a linear actuator to run the boom and the bucket. My problem is I want the servo to recognize end points so that it doesn’t extend the boom too far thus breaking the plastic excavator booms. Is there anyway to set the continuous rotation “hacked” servo to stop at certain points? So in essence when it reached a set destination the motor would stop until the reverse input was provided. I hope that makes sense.
Do you have any idea who sells Lead Screw material. I would be looking for 3/16" or 1/4" material? Thanks
Using a drill bit instead of a lead screw will cause issues (a drill bit is meant to remove material whereas a lead screw can be used as a linear actuator. If you want the system to “know” it has reached an end position, you would need a microcontroller as well as a pair of limit switches. The other approach is to use an RC linear actuator:
robotshop.com/en/firgelli-actuators.html
We offer many microcontrollers 
robotshop.com/en/microcontrollers.html?___SID=U
Some help choosing the right one:
robotshop.com/blog/en/how-to-make-a-robot-lesson-4-understanding-microcontrollers-2-3700
We sell limit switches too.
Yes - when the traveller pressed the limit switch, that would make the digital pin which it’s connected to go “high”; the microcontroller would be waiting for this and cause the motor to stop.
If you’re ready to do most of the work on your own and learn about robotics, this forum is the right place. If you want someone to help you design and possibly build it, that’s a consultation company 
Learning how to program is like learning a new language. It takes, time, patience and experience.
We have one possible supplier of threaded rod (various thread lengths - it does not go by diameter), though they only offer 12" long sections. Would this be of interest?
Good Point!! I didn’t even think about that about the bit causing problems, friction being one of them. Where would I get a microcontroller at, is it something you guys sell? I know I can get the limit switches at here locally. So I would have to have hardware physically attached that would trigger the switches on either side, is that correct? Is there a forum that you’re aware of that would help with this? Thanks for your help.
So I have looked at a few videos on how to program but they don’t make much sense. How hard would it be to program the servo, also will all this work with a RC receiver which would control the servo.
And yes I prefer to do the work myself and learn how all this works. Sorry I just noticed you answered my questions. Not familiar with the thread yet:D