Stepper Motor L298n

step.py

import RPi.GPIO as GPIO
import sys
import time
GPIO.setmode(GPIO.BOARD)
flow_rate_map = dict([(1, 50), (2, 100), (3, 150), (4, 200), (5, 250)])
control_pins = [15,13,11,12]

# Load the current flow rate from the local db.txt file
db = open("db.txt","r")
current_flow_rate = int(db.read().rstrip('\n'))
db.close()
print("Current Flow Rate: ", current_flow_rate)

selected_flow_rate = int((sys.argv)[1])
print("Selected Flow Rate: ",selected_flow_rate)

# Exit if an invalid flow rate is entered
if selected_flow_rate < 1 or selected_flow_rate > 5:
    print("Invalid value. Terminating!")
    raise SystemExit

# Do nothing if the current flow are is the same as the selected flow rate
if selected_flow_rate == current_flow_rate:
    print("!!Exiting!! Selected flow rate is already :", current_flow_rate)
    raise SystemExit

# if selected_flow_rate > current_flow_rate:
step_value = flow_rate_map[selected_flow_rate] - flow_rate_map[current_flow_rate]
print("Step value: ",step_value)

# Reverse the control_pins array if we need to go anti-clockwise
if step_value < 0:
    control_pins = control_pins[::-1]
    
for pin in control_pins:
    GPIO.setup(pin, GPIO.OUT)
    GPIO.output(pin, 0)
    halfstep_seq = [
      [1,0,0,0],
      [1,1,0,0],
      [0,1,0,0],
      [0,1,1,0],
      [0,0,1,0],
      [0,0,1,1],
      [0,0,0,1],
      [1,0,0,1]
    ]
for i in range(abs(step_value)):
  for halfstep in range(8):
    for pin in range(len(control_pins)):
      GPIO.output(control_pins[pin], halfstep_seq[halfstep][pin])
      time.sleep(0.001)
GPIO.cleanup()

# Save the new flow rate
db = open("db.txt","w")
db.write(str(selected_flow_rate))
db.close()
print("Current Flow Rate is now: ", selected_flow_rate)