import machine
import sdcard
import os
import time

# Define pin connections
ldr_pin = machine.ADC(26)  # LDR sensor connected to Pin GP26 (ADC0)
spi = machine.SPI(0, baudrate=1000000, sck=machine.Pin(18), mosi=machine.Pin(19), miso=machine.Pin(16))
cs_pin = machine.Pin(17)  # CS pin for SD card

# Initialize microSD card
sd = sdcard.SDCard(spi, cs_pin)

# Function to read LDR sensor data
def read_ldr():
    ldr_value = ldr_pin.read_u16()
    return ldr_value

# Function to log data to SD card
def log_data(ldr_value):
    with open('/sd/ldr_log.txt', 'a') as file:
        file.write("{},{}\n".format(time.time(), ldr_value))

# Mount the SD card
os.mount(sd, '/sd')

# Main loop
try:
    while True:
        # Read LDR sensor data
        ldr_value = read_ldr()
        
        # Log data to SD card
        log_data(ldr_value)
        
        # Print data (optional)
        print("LDR Value:", ldr_value)
        
        # Delay before next reading
        time.sleep(1)  # Adjust delay as needed

except KeyboardInterrupt:
    # Unmount the SD card and clean up
    os.umount('/sd')