binaural_beats.py

# Binaural Beats Generator
#
# Streamlit applet to generate binaural beats.
# User can set Duration (seconds), Carrier Frequency (Hz), and Beat Frequency (Hz).
# Generated WAV file can be downloaded from link below graphs.
#
import streamlit as st
import numpy as np
import scipy.io.wavfile
from scipy.signal import windows
from io import BytesIO
import matplotlib.pyplot as plt
import base64


def generate_binaural_beats(duration, carrier_frequency, beat_frequency, sample_rate, amplitude):
    time = np.linspace(0, duration, duration * sample_rate)
    left_wave = amplitude * \
        np.sin(2 * np.pi * (carrier_frequency - beat_frequency / 2) * time)
    right_wave = amplitude * \
        np.sin(2 * np.pi * (carrier_frequency + beat_frequency / 2) * time)
    return left_wave, right_wave


def save_wav_file(sample_rate, left_wave, right_wave, file_name):
    stereo_data = np.array([left_wave, right_wave]).T
    scipy.io.wavfile.write(file_name, sample_rate,
                           stereo_data.astype(np.float32))


st.title("Binaural Beats Generator")

duration = st.slider("Duration (seconds)", min_value=1,
                     max_value=60, value=10, step=1)
carrier_frequency = st.slider(
    "Carrier Frequency (Hz)", min_value=20, max_value=1000, value=440, step=1)
beat_frequency = st.slider("Beat Frequency (Hz)",
                           min_value=1, max_value=50, value=10, step=1)

if st.button("Generate Binaural Beats"):
    sample_rate = 44100
    amplitude = 0.5

    left_wave, right_wave = generate_binaural_beats(
        duration, carrier_frequency, beat_frequency, sample_rate, amplitude)
    save_wav_file(sample_rate, left_wave, right_wave, "binaural_beats.wav")

    st.success("Binaural beats generated successfully!")

    # Plot the first second of the left and right waves
    time = np.linspace(0, 1, sample_rate)
    fig, ax = plt.subplots(2, 1, figsize=(10, 6), sharex=True)
    ax[0].plot(time, left_wave[:sample_rate], label="Left Channel")
    ax[0].legend()
    ax[0].grid()
    ax[1].plot(time, right_wave[:sample_rate],
               label="Right Channel", color="r")
    ax[1].legend()
    ax[1].grid()
    ax[1].set_xlabel("Time (s)")
    st.pyplot(fig)

    # Create a download link for the WAV file
    with open("binaural_beats.wav", "rb") as f:
        wav_file = f.read()

    b64_file = base64.b64encode(wav_file).decode("utf-8")
    href = f'<a href="data:file/wav;base64,{b64_file}" download="binaural_beats.wav">Download Binaural Beats WAV File</a>'
    st.markdown(href, unsafe_allow_html=True)