from machine import Pin,ADC,PWM
import time
btn1=Pin(0,Pin.IN,Pin.PULL_UP)
btn2=Pin(1,Pin.IN,Pin.PULL_UP)
led1=PWM(Pin(2,Pin.OUT))
adc=ADC(Pin(26))
led1.duty_u16(adc.read_u16())
led1.freq(50)
dt=1
while True:
    led1.duty_u16(adc.read_u16())
    if btn1.value()==0:
        dt=min(3,dt+0.5)
    if btn2.value()==0:
        dt=max(0.5,dt-0.5)
    time.sleep(dt)
    led1.duty_u16(0)
    time.sleep(dt)