magnetometer.py

import numpy as np
import time

EARTH_FIELD = np.array([22.0, 0.0, -44.0])
NOISE_STD = 0.2

def read(x, y, z):
    noise = np.random.normal(0, NOISE_STD, 3)
    field = EARTH_FIELD + noise
    return {
        "Bx": float(field[0]),
        "By": float(field[1]),
        "Bz": float(field[2]),
        "timestamp": time.time()
    }