from machine import Pin,ADC,PWM
from time import sleep

adc=ADC(Pin(13))
adc.atten(ADC.ATTN_11DB)
adc.width(ADC.WIDTH_10BIT)

frequency=5000
led=PWM(Pin(2),frequency)

while True:
    ldrval=adc.read()
    ldrvolt=ldrval*(3.3/1024)
    print("ldr value = ",ldrval)
    print("voltage = ",ldrvolt, "\n")
    sleep(1)
    led.duty(ldrval)