import machine
from utime import sleep

# Constants
V_in = 3.3
ADC_MAX_VALUE = 65535
R_fixed = 10000  # Fixed resistor value in ohms
threshold = 5000  # ADC threshold

# Initialize the LED and ADC pins
led_pin = machine.Pin(27, machine.Pin.OUT)
ldr = machine.ADC(28)

def adc_to_voltage(adc_value):
    """Convert ADC reading to voltage."""
    return adc_value * V_in / ADC_MAX_VALUE

def voltage_to_resistance(voltage):
    """Convert voltage to LDR resistance."""
    return R_fixed * (V_in / voltage - 1)

def resistance_to_lux(resistance):
    """Convert LDR resistance to lux value."""
    return 500 / (resistance / 1000)  # Example conversion, adjust based on LDR datasheet

while True:
    # Read the LDR value
    ldr_value = ldr.read_u16()
    voltage = adc_to_voltage(ldr_value)
    resistance = voltage_to_resistance(voltage)
    lux = resistance_to_lux(resistance)

    if ldr_value > threshold:
        led_pin.on()
    elif ldr_value < threshold:
        led_pin.off()

    sleep(0.25)