from machine import Pin, ADC
from utime import sleep
sensor = ADC(26)
green_led = Pin(16, Pin.OUT)
red_led = Pin(18, Pin.OUT)
while True:
    raw = sensor.read_u16()
    voltage = raw * 3.3 / 65535
    print("voltage is",voltage)
    if voltage > 2.5:
        red_led.value(1)
        green_led.value(0)
    elif voltage > 1.0:
        red_led.value(0)
        green_led.value(1)
    else:
        red_led.value(0)
        green_led.value(0)
    sleep(0.1)