csv.log

import time
import numpy as np
import datetime
from ADCDifferentialPi import ADCDifferentialPi
import csv
import os
import atexit  # closes file if loop crashes

SENSITIVITY = 50000  # nT per volt

OFFSET_1 = 0.0
OFFSET_2 = 0.0
OFFSET_3 = 0.0

adc = ADCDifferentialPi(0x68, 0x69, 18)

# ---------------- FILE STATE ----------------
current_date = None
csv_file = None
csv_writer = None

# ---------------- CLEAN EXIT ----------------
def close_file():
    if csv_file is not None:
        csv_file.close()

atexit.register(close_file)

# ================= MAIN LOOP =================
while True:

    # ---------- UTC TIME ----------
    current_time = datetime.datetime.utcnow()
    date_str = current_time.strftime("%Y-%m-%d")
    time_str = current_time.strftime("%H:%M:%S")

    # ---------- SENSOR ----------
    bx = (adc.read_voltage(1) - OFFSET_1) * SENSITIVITY
    by = (adc.read_voltage(2) - OFFSET_2) * SENSITIVITY
    bz = (adc.read_voltage(3) - OFFSET_3) * SENSITIVITY

    b_total = np.sqrt(bx**2 + by**2 + bz**2)

    # ---------- CSV FILE HANDLING ----------
    if date_str != current_date:
        if csv_file is not None:
            csv_file.close()

        os.makedirs("data", exist_ok=True)
        filename = f"data/geomagnetic_{date_str}.csv"
        file_exists = os.path.isfile(filename)

        csv_file = open(filename, "a", newline="")
        csv_writer = csv.writer(csv_file)

        if not file_exists:
            csv_writer.writerow([
                "Date (UTC)", "Time (UTC)",
                "Bx (nT)", "By (nT)", "Bz (nT)", "Total (nT)"
            ])

        current_date = date_str

    # ---------- CSV LOG (EVERY SECOND) ----------
    if csv_writer is not None:
        csv_writer.writerow([date_str, time_str, bx, by, bz, b_total])
        csv_file.flush()

    # ---------- SAMPLING RATE ----------
    time.sleep(1)