from machine import Pin 
import time
import sdcard
import dht
import uos

# Assign chip select (CS) pin (and start it high)
cs = machine.Pin(1, machine.Pin.OUT)

# Intialize SPI peripheral (start with 1 MHz)
spi = machine.SPI(0,
                  baudrate=1000000,
                  polarity=0,
                  phase=0,
                  bits=8,
                  firstbit=machine.SPI.MSB,
                  sck=machine.Pin(2),
                  mosi=machine.Pin(3),
                  miso=machine.Pin(4))

# Initialize SD card
sd = sdcard.SDCard(spi, cs)

# Mount filesystem
vfs = uos.VfsFat(sd)
uos.mount(vfs, "/sd")

# Defining sensor pins 
light_sensor_pin = Pin(17)
dht_sensor = dht.DHT22(Pin(14))
adc = ADC(28)

# Defining filter window size [number of samples to average]
filter_window_size = 5

# Initialize variables to store past sensor readings
past_temp_readings = [0] * filter_window_size
past_light_readings = [0] * filter_window_size
current_filter_index = 0

# Function to read temperature and humidity
def read_temperature():
    try:
        dht_sensor.measure()
        return dht_sensor.temperature()
    except Exception as e:
        print("Failed to read from DHT sensor:", e)
        return None

# Function to read light sensor
def read_light():
    d = adc.read_u16()
    volt=3.3*(d/65535) 
    resistance  = 2000 * volt / (1 - volt / 5)
    lux  = pow(50 * 1e3 * pow(10, 0.7) / resistance, (1 / 0.7))
    return lux
    
# Function to apply moving average filter
def apply_moving_average(data_list, new_value):
    # Add new value to the list and remove the oldest value
    data_list[current_filter_index] = new_value
    current_filter_index = (current_filter_index + 1) % filter_window_size
    
    # Calculate the average of the data points in the list
    return sum(data_list) / len(data_list)

while True:
    # Read sensor data
    raw_temperature = read_temperature()
    raw_light_level = read_light()

    # Apply moving average filter to sensor data
    filtered_temperature = apply_moving_average(past_temp_readings, raw_temperature)
    filtered_light_level = apply_moving_average(past_light_readings, raw_light_level)

    # Get current timestamp
    timestamp = time.time()

    # Format data for storage
    data_string = f"{timestamp},{filtered_temperature},{filtered_light_level}\n"

    # Open file for data appending
    with open("/sd/data.txt", "a") as f:
        f.write(data_string)

    # Adjust sleep time based on desired data collection frequency
    time.sleep(5)  # Collect data every 5 seconds

# Unmount SD card when finished (optional)
sd.umount(vfs)