# from machine import Pin, ADC
# from time import sleep
 
# ldr = ADC(27)
 
# while True:
#     voltage =  ldr.read_u16() / (65535 * 3.3)
#     resistance = 2000 * voltage / (1 - voltage / 5);
#     lux = pow(50 * 1e3 * pow(10, 0.7) / resistance, (1 / 0.7));
#     print(lux)
#     sleep(2)

#      #(250 / ldr.read_u16())-50

# from machine import ADC, Pin
# import time


# class LDR:
#     """This class read a value from a light dependent resistor (LDR)"""

#     def __init__(self, pin, min_value=0, max_value=100):
#         """
#         Initializes a new instance.
#         :parameter pin A pin that's connected to an LDR.
#         :parameter min_value A min value that can be returned by value() method.
#         :parameter max_value A max value that can be returned by value() method.
#         """

#         if min_value >= max_value:
#             raise Exception('Min value is greater or equal to max value')

#         # initialize ADC (analog to digital conversion)
#         self.adc = ADC(Pin(pin))

#         # set 11dB input attenuation (voltage range roughly 0.0v - 3.6v)
#         self.adc.atten(ADC.ATTN_11DB)

#         self.min_value = min_value
#         self.max_value = max_value

#     def read(self):
#         """
#         Read a raw value from the LDR.
#         :return A value from 0 to 4095.
#         """
#         return self.adc.read()

#     def value(self):
#         """
#         Read a value from the LDR in the specified range.
#         :return A value from the specified [min, max] range.
#         """
#         return (self.max_value - self.min_value) * self.read() / 4095


# # initialize an LDR
# ldr = LDR(27, 0, 65537)

# while True:
#     # read a value from the LDR
#     value = ldr.value()
#     print('value = {}'.format(value))

#     # a little delay
#     time.sleep(3)

from machine import Pin, ADC
from time import sleep
 
ldr = ADC(27)

MAX_ADC_READING = 65535;
ADC_REF_VOLTAGE = 3.3;
REF_RESISTANCE = 50;
LUX_CALC_SCALAR = 12518931;
LUX_CALC_EXPONENT = -1.405;
 
while True:
    rawData = ldr.read_u16()
    print(f"Raw data: {rawData}")

    resistorVoltage = rawData / MAX_ADC_READING * ADC_REF_VOLTAGE;
    print(f"Resistor voltage: {resistorVoltage}")

    ldrVoltage = ADC_REF_VOLTAGE - resistorVoltage;
    print(f"LDR voltage: {ldrVoltage}")

    ldrResistance = ldrVoltage/resistorVoltage * REF_RESISTANCE;
    print(f"LDR resistance: {ldrResistance}")

    ldrLux = LUX_CALC_SCALAR * pow(ldrResistance, LUX_CALC_EXPONENT);
    print(f"Lux: {ldrLux}")

    print("==========")

    sleep(2)