from machine import ADC,Pin,Timer

LDR = ADC(Pin(15))

GAMMA = 0.7
RL10 = 50


def fun(tim):
    #print(LDR.read())

    global GAMMA
    global RL10

    analongValue = LDR.read()
    voltage = analongValue/4096.*5
    resistance = 2000*voltage/(1 - voltage/5)
    lux = pow(RL10*1e3*pow(10,GAMMA)/resistance,(1/GAMMA))
    print(lux)

tim = Timer(1)
tim.init(period = 500,mode = Timer.PERIODIC,callback = fun)