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

adc = ADC(Pin(34))
adc.atten(ADC.ATTN_11DB)   # sets for a maximum input voltage of 3.6 volts
adc.width(ADC.WIDTH_9BIT) # sets the bit width to 12 bits


pwm0 = PWM(Pin(21))
pwm0.freq(50)


tim0 = Timer(0)

pwm0.duty(25)


switch =0

step=25
val = 0

def handler_0(tim0):
  global val
  global step
 

  if step < 125:
    pwm0.duty(step)
    step=step+1
    val=step
   
  elif step > 124:
    pwm0.duty(val)
    val=val-1
    if val < 26:
      step=val
  

  

while True:
  adc_value = adc.read()
  volts = (3.3*adc_value)/511
  if 0 <= volts <= 0.5:
    pwm0.duty(25)
    switch = 0
    tim0.deinit()

  elif 0.5 <= volts <= 1:
    pwm0.duty(50)
    switch = 0
    tim0.deinit()

  elif 1 <= volts <= 1.5:
    pwm0.duty(75)
    switch = 0
    tim0.deinit()

  elif 1.5 <= volts <= 2:
     pwm0.duty(100)
     switch = 0
     tim0.deinit()
  
  elif 2 <= volts <= 2.5:
     pwm0.duty(125)
     switch = 0
     tim0.deinit()

  else:
    if switch == 0:
      switch = 1
      tim0 = Timer(0)
      tim0.init(period=100, mode=Timer.PERIODIC, callback=handler_0)
    


  input_voltage = "The input voltage is {:0.3f} volts and raw value is {:4d}"
  print(input_voltage .format(volts,adc_value,switch),end = "\r")