46: Linear Stepper Motor -- More
-- revised 9/15/16 --

Below is a very messy circuit drawing for my Arduino setup. Should also work with Particle Photon or Raspberry Pi. It uses external 5V to power both the relay switch and the motor. The reason for the relay is that the steppers draw power constantly. So in my program when I want to move the linear screw I turn the power ON, delay(100), operate the stepper, delay(100) and turn the relay OFF. When you power a stepper off the rotor can move freely (no brakes). But with the linear screw that won't happen (its own friction). My cheap stepper has about a 3" movement. Even with counting steps, I will use a door/window sensor to recalibrate the initial position. I plan to use this to dispense dog treats. See post 41.

Revised: I bought a second EasyDriver and motor. They look exactly like the above. After the irritating soldering adventure I hooked it up to an Arduino Nano and loaded the same script that I used with the first pair. With the first set, 350 steps move the length of the spiral screw; the new one takes over 1500. No clue as to why.