import time
import board
import analogio
import digitalio

ldr = analogio.AnalogIn(board.GP26)
rele = digitalio.DigitalInOut(board.GP18)
rele.direction = digitalio.Direction.OUTPUT

def get_voltage(raw):
    return (raw * 3.3) / 65536

while True:
    raw = ldr.value
    volts = get_voltage(raw)
    print("Dec = {:5d} volts = {:5.2f}". format (raw, volts))
    if volts > 1.65:
       rele.value = True
    else:
        rele.value = False 
    time.sleep(0.3)