Wi-Fi Spectrum Analyzer written in Python

wifi-spectrum-analyzer.py

import matplotlib.pyplot as plt
import pandas as pd
import numpy as np
import subprocess
import re

all_colors = ['tab:blue', 'tab:orange', 'tab:green', 'tab:red', 'tab:purple', 'tab:brown', 'tab:pink', 'tab:gray', 'tab:olive', 'tab:cyan']
plt.style.use('dark_background')

while True:
    # Scan for other local Wi-Fi networks
    stdoutlines = []
    command_line = 'system_profiler SPAirPortDataType | grep -A 9999  "Other Local Wi-Fi Networks:"'
    p = subprocess.Popen(command_line, shell=True, stdout=subprocess.PIPE)
    stdoutlines = [line.lstrip() for line in p.communicate()[0].decode().split('\n')]

    # Parse the output and get the SSID, channel, bandwidth and RSSI
    scanned_ssid = []
    for line in stdoutlines:
        if line.endswith(':') and stdoutlines.index(line) != 0:
            scanned_ssid.append(line.split(':')[0])
        if line.startswith('Channel:'):
            channel = re.search('Channel: \d+', line)
            if channel:
                res = channel.group().split()
                scanned_ssid.append(res[-1])
            bandwidth = re.search('\d+MHz', line)
            if bandwidth:
                res = bandwidth.group().split('MHz')
                scanned_ssid.append(res[0])
        if line.startswith('Signal / Noise:'):
            rssi = re.search('-\d+', line)
            if rssi:
                res = rssi.group().split()
                scanned_ssid.append(res[0])

    # Reformat scanned_ssid into a list of tuples
    data = []
    for ssid, channel, bandwidth, rssi in zip(scanned_ssid[::4], scanned_ssid[1::4], scanned_ssid[2::4], scanned_ssid[3::4]):
        data.append((ssid, channel, bandwidth, rssi))

    # Convert the list of tuples into a dataframe
    df = pd.DataFrame(data, columns=['ssid', 'channel', 'bandwidth', 'rssi'])

    # Clear and redraw the plot
    plt.clf()
    plt.xlabel('Wi-Fi Channel')
    plt.ylabel('RSSI [dBm]')
    plt.grid(axis='y', linestyle='--')
    plt.grid(axis='x', linestyle=':', color='r', alpha=0.3)

    y_major_ticks = np.arange(-20, -100, -10)
    plt.gca().set_yticks(y_major_ticks)

    x_major_ticks = np.arange(0, 16, 1)
    plt.gca().set_xticks(x_major_ticks)

    plt.ylim(-99, -20)
    plt.xlim(-2, 16)

    # Plot the points
    for index, row in df.iterrows():
        bw = int(row['bandwidth'])
        ch = int(row['channel'])
        rs = int(row['rssi'])

        diff = bw / 5
        
        x = np.linspace(ch-diff, ch+diff, 50)
        y = (-99 - rs) * np.sin((x - ch + 2) / diff * np.pi)
        y = -99 - y
        
        color = all_colors[ index % len(all_colors) ]
        
        plt.fill(x, y, color=color, alpha=0.3)
        plt.plot(x, y, color=color)    
        plt.text(ch, rs+1, row['ssid'], horizontalalignment='center')
        plt.draw()
        plt.pause(0.01)

The code is based on the following reference:
https://stackoverflow.com/questions/68435744/how-to-draw-wifi-channel-graph-with-python-programming