nema 17 is used in a robot arm. Tobias Kuhn watched a video on YouTube about a robotic arm using a servo motor that he wanted to make himself.
But he found it difficult to make the servo system move slowly or smoothly. Even removing the single chip from Arduino Nano and trying to use servo driver IC and potentiometer did not satisfy him.
Then he found a very affordable nema 17. After some experiments, he proposed a smoothly moving robot arm with four stepper controls from an Arduino Mega and A4988 stepper motor drivers.
Instead of writing a bunch of stepper motor codes, he installed and ran grbl’s four-axis bifurcation on Arduino, turning it into a stepper motor controller.
A minor problem is that the A4988 stepper motor driver is driven by bipolar stepper motor, but the nema 17 he has is unipolar. Fortunately, he knows a very simple method. Our Brian Benchoff wrote about how to convert a unipolar motor into a bipolar one.
When he operated on the replica, the potentiometer’s value was read by the raspberry pie and some custom Python code, which sent the appropriate G code to the robot arm controlled by Arduino/grbl.
There was a slight delay, but when he moved the replica arm, the arm would do the same thing. In order to tell the manipulator what to do, he made a replica arm with potentiometer to replace the nema 17.