EEG Simulator Example Base

# mini_sim.py — 19ch toy EEG (alpha, beta, blink) + optional BrainVision export
import numpy as np

CHS = ['Fp1','Fp2','F7','F3','Fz','F4','F8','T3','C3','Cz','C4','T4','T5','P3','Pz','P4','T6','O1','O2']
fs, dur = 256, 20.0                                   # Hz, seconds
t = np.arange(int(fs*dur)) / fs
nch = len(CHS)
data = np.zeros((nch, t.size))

def add_sine(ch_names, freq, amp):
    sig = amp * np.sin(2*np.pi*freq*t) * (1 + 0.2*np.sin(2*np.pi*0.1*t))  # slow AM for realism
    for name in ch_names:
        i = CHS.index(name)
        data[i] += sig

# rhythms
add_sine(['O1','O2','P3','P4'], freq=10.0, amp=30.0)  # posterior alpha
add_sine(['F3','F4','Fz'],       freq=18.0, amp=12.0) # frontal beta
add_sine(['Cz'],                  freq=25.0, amp=10.0) # central 25 Hz

# noise
rng = np.random.default_rng(0)
data += rng.normal(0, 5.0, size=data.shape)           # ~5 µV noise

# one blink (~200 ms) frontopolar positive deflection
blink_t0 = int(5.0*fs)
blink_len = int(0.2*fs)
blink = 150.0 * np.hanning(blink_len)                 # ~150 µV
for ch in ['Fp1','Fp2']:
    i = CHS.index(ch)
    data[i, blink_t0:blink_t0+blink_len] += blink

# OPTIONAL: save as BrainVision if MNE is available
if __name__ == "__main__":
    try:
        import mne
        info = mne.create_info(CHS, sfreq=fs, ch_types='eeg')
        raw = mne.io.RawArray(data*1e-6, info)        # µV → Volts
        raw.set_montage('standard_1020', on_missing='ignore')
        mne.export.export_raw('mini.vhdr', raw, fmt='brainvision')
        print("Wrote BrainVision files: mini.vhdr/vmrk/eeg")
    except Exception as e:
        print("MNE not installed or export failed; skipping file export:", e)