Python Forum

Hello,
I've been working on a turret that uses a 24-byj stepper motor to control the x axis and an sg-90 servo to control the y axis. Through my raspberry pi I was able to control both with a program I wrote. The problem I'm having is that when both are running, the stepper motor moves slower to the left than usual and does not move to the right at all, and I have tried using an external power source.

import RPi.GPIO as GPIO
import time
import curses

servo_value = 9
screen = curses.initscr()
curses.noecho() 
curses.cbreak()
screen.keypad(True)

try:
    GPIO.setmode(GPIO.BOARD)
    GPIO.setup(3, GPIO.OUT)
    servo1 = GPIO.PWM(3, 50)
    
    ControlPin = [7,11,13,15]

    for pin in ControlPin:
        GPIO.setup (pin, GPIO.OUT)
	GPIO.output (pin, 0)
	
    seq2 = [[1,0,0,0],
            [1,0,0,0],
            [0,1,0,0],
            [0,1,0,0],
            [0,0,1,0],
            [0,0,1,0],
            [0,0,0,1],
            [0,0,0,1],
            [1,0,0,0],]

    seq3 = [[1,0,0,0],
            [0,0,0,1],
            [0,0,0,1],
            [0,0,1,0],
            [0,0,1,0],
            [0,1,0,0],
            [0,1,0,0],
            [1,0,0,0],
            [1,0,0,0],]
        
    while True:
        
        servo1.start(servo_value)
        
        char = screen.getch()
        if char == ord('q'):
            break
        elif char == curses.KEY_UP:
            print("key up pressed")
            servo_value = servo_value + 0.25
            servo1.ChangeDutyCycle(servo_value)
            print(servo_value)
            time.sleep(0.001)

        elif char == curses.KEY_DOWN:
            print("key down pressed")
            servo_value = servo_value - 0.25
            servo1.ChangeDutyCycle(servo_value)
            print(servo_value)
            time.sleep(0.001)
            
                    # right turning
        elif char == curses.KEY_RIGHT:
            for i in range(15):
                print("right")
                for halfstep in range(9):
                    for pin in range(4):
                        GPIO.output(ControlPin[pin], seq2[halfstep][pin])
                        time.sleep(0.001)
                        
                        # left turning
        elif char == curses.KEY_LEFT:
            for i in range(15):
                print("left")
                for halfstep in range(9):
                    for pin in range(4):
                        GPIO.output(ControlPin[pin], seq3[halfstep][pin])
                        time.sleep(0.001)
    GPIO.cleanup()
    
except AttributeError:
    servo1.stop()
    GPIO.cleanup()

This is some time ago for me, but is it a software or hardware problem?
They sell controllers ('drivers) to connect multiple motors working together in the same project.
(6 servo, 12 servo, 24 servo...etc). There are zillions of models like : https://www.pololu.com/product/1350
I am unsure if you can connect 2 different types to the same controller though.(servo,stepper)
Paul

see also: https://pypi.org/search/?q=stepper&o=-zscore

The servo is connected directly to the pi but im using a UNL2003 driver for the stepper motor.

OK, UNL2003 is the one for the stepper.
Judging a hardware project from a distance is tricky.
One suggestion/test: invest in a second servo to replace the stepper and a controller for the 2 servos.
(Should be around 10$) They do articulated cranes with 4 servos, not unlike a turret.
Doing that , i would look into post #3, seems interesting.
If you have tower pros, always check on their webpage if you have the genuine article;
They are the best, but also the most faked. You can tell by the way the logo is printed
Paul