from machine import Pin
from time import sleep

adc =machine.ADC(Pin(27))
step_pin= Pin(3,Pin.OUT)

#the greater the intensity of light, the greater the RPM of the motor
while True:
    x=adc.read_u16()
    y=(0.000124*x)-0.03488
    step_pin.value(1)
    step_pin.value(0)
    sleep(y/1000)