I’ll start off by admitting that I am a big newbie when it comes to a lot of this. I’ve just started digging around and reading but I figured I’d post up my little project I’m slowly starting to move forward with. I will gladly accept any tips or recommendations anyone might have on what I would need/how to accomplish this task.
I would like to have a worm gear motor connected to a vertical threaded shaft. On this threaded shaft would be an “arm”. When the motor turns the shaft, the arm would move up or down the threaded shaft depending on the direction the motor is rotating the shaft.
Now…
I would like to program the motor to turn X amount of rotations, lets say clockwise. (Moving the arm from the top of the threaded shaft toward the bottom.)
When the motor has completed X amount of rotations, I would like it to automatically stop and reverse X amount of times in the opposite direction returning the arm to it’s orginal starting spot.
When the arm is returned to it’s orginal starting point, I would like it to stop until the “start” button is pushed again.
You want a leadscrew turned by a geared DC motor, or a stepper motor.
With the stepper, you can just count the revs.
With the DC geared motor, you’d use limit switches.
A small microprocessor board can control either of the motors.
Thanks for your reply! Yes, a leadscrew (with a arm) and I would think a stepper would work best for me then. Limiting switches may not be the best because there would be times that I would like to change the downard distance the arm travels.
Being able to program the motor to make 36 revs clockwise, reverse 36 revs counter clockwise and stop seems like a simpler way to go about it…?
So now motor control…
I’d also like to have the choice of a few buttons, for example:
Button 1 - starts revs 36 clockwise/36 counter and stops
Button 2 - starts revs 42 clockwise/42 counter and stops
Button 3 - starts revs 46 clockwise/46 counter and stops
I’d like to program speed of revs.
I’d like the option of controlling 2 or more motors also.
A DC linear actuator is essentially a DC motor, connected to spur gears, and the final spur gear rotates a lead screw.
That lead screw moves a traveler closer or farther, creating linear motion.
Rather than an encoder, they simply measure the linear distance using a potentiometer.
Ex: robotshop.com/en/firgelli-te … -12-i.html
Ex: robotshop.com/en/4-stroke-15 … meter.html
I would need the leadscrew to move the traveler (aka my arm) a distance anywhere between 18 to 22 inches…
Here’s a quick rough sketch I did on my note of a box which would house everything. In this sketch I only show the box, lead screw, and traveler (arm). The lead screw would be vertical allowing the traveler to move up and down.
If you can’t consider a linear actuator, you’ll need to essentially make a “stripped down” version of one.
Consider a DC motor with encoder (or a stepper motor) and a limit switch.
You’ll need to do some programming, and you’ll need a microcontroller and a motor controller.
We don’t have a motor which is already connected to a lead screw, and our selection of gears is quite limited.
Why do you need the worm gear?
I just figure that by using a worm drive type of system it would cut down the overall height of the unit… since I’m already looking for 18 to 22 inches of travel I would like to keep the overall height of the complete unit to a minimum. I have more wiggle room when it comes to the width of the unit than I do the height.
I wouldn’t worry about a worm gear, a simple planetary drive gear motor of about 100 RPM or so should work. Use a 3/16" (1/4-20?) or so threaded rod. The following nut gives you your movement.
for around a 20 tpi pitch, you can just count rotations with a simple slotted disk interrupter sensor. You might also want a “bottom” sensor to set the limit of travel.
