from machine import Pin,ADC
from utime import sleep
photPIN = 28
def readLight(photoGP):
    photoRes = ADC(Pin(28))
    light = photoRes.read_u16()
    light = round(light/65535*100,2)
    return light
while True:
    print("light: " + str(readLight(photPIN)) + "%")
    sleep(1)