HOW to Make a Variable Speed Fan with Kidspico

'''
 * Filename    : Gearshift mode
 * Thonny      : Thonny 4.1.4
 * Auther      : http//www.keyestudio.com
'''
from machine import Pin,PWM,ADC
import time

key = ADC(26)

# set INA and INB to PWM pins
pwm_INA = PWM(Pin(14)) 
pwm_INB = PWM(Pin(15)) 
 
# set PWM frequency. The frequency depends on the motor application.
pwm_INA.freq(500)
pwm_INB.freq(500)
 
# Set the maximum and minimum rotation speed
max_duty = 65535
min_duty = 0
 
# Linear interpolation is used to calculate duty values for different speeds
def calc_duty(speed):
    speed = int(speed * (max_duty - min_duty) / 100 + min_duty)
    return speed
 
# change the rotation speed
def set_speed_INA(speed):
    duty = calc_duty(speed)
    pwm_INA.duty_u16(duty)

# change the rotation speed
def set_speed_INB(speed):
    duty = calc_duty(speed)
    pwm_INB.duty_u16(duty)
    
while True:
    key_value = key.read_u16()

    if key_value < 10000:   # no key  is pressed
        pass

    elif key_value < 14000: # SW5 is pressed
        set_speed_INA(0)
        set_speed_INB(40)

    elif key_value < 27000: # SW4 is pressed
        set_speed_INA(0)
        set_speed_INB(60)

    elif key_value < 40000: # SW3 is pressed
        set_speed_INA(0)
        set_speed_INB(80)

    elif key_value < 53000: # SW2 is pressed
        set_speed_INA(0)
        set_speed_INB(100)

    else:                   # SW1 is pressed                 
        set_speed_INA(0)
        set_speed_INB(0)
    time.sleep(0.1)