WIFI Measurement Pi

from RPLCD import CharLCD
from time import sleep
import subprocess, re, csv

from RPi import GPIO

lcd = CharLCD(cols=16, rows=2, pin_rs=40, pin_e=38, pins_data=[37, 35, 33, 31], numbering_mode=GPIO.BOARD, backlight_enabled=False)

CLEANED = 0

def cleanup():
    global CLEANED
    if not CLEANED:
        lcd.clear()
        GPIO.cleanup()
        CLEANED = 1
    else:
        pass

# ---------- CODE ---------- #

PATTERN = re.compile(r'Link Quality=((\d\d)/(\d\d))\s{1,3}Signal level=(([\+|\-]\d\d)\sdBm)')

def write_to_lcd(framebuffer, num_cols=16, lcd=lcd):
    lcd.home()
    for row in framebuffer:
        lcd.write_string(row.ljust(num_cols)[:num_cols])
        lcd.write_string('\r\n')

def fetch_strength():
    cmd = ['iwconfig', 'wlan0']
    result = subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True)
    m = re.search(PATTERN, str(result))
    quality_nice, signal_nice, quality_raw_n, quality_raw_d, signal_raw = str(m.group(1)), str(m.group(4)), int(m.group(2)), int(m.group(3)), int(m.group(5))
    return quality_nice, signal_nice, quality_raw_n, quality_raw_d, signal_raw

def record_stats(reading, quality_raw_n, quality_raw_d, signal_raw):
    with open('stats.csv', mode='a') as f:
        writer = csv.writer(f, delimiter=',', quotechar='"', quoting=csv.QUOTE_MINIMAL)
        writer.writerow([reading, quality_raw_n, quality_raw_d, signal_raw])

# ---------- MAIN ---------- #
if __name__ == "__main__":

    framebuffer = ['Quality: ', 'Signal: ']
    reading = 1

    try:
        while True:
            try:
                quality_nice, signal_nice, quality_raw_n, quality_raw_d, signal_raw = fetch_strength()
                display = [f'{framebuffer[0] + quality_nice}', f'{framebuffer[1] + signal_nice}']
                record_stats(reading, quality_raw_n, quality_raw_d, signal_raw)
                print(f'Readings taken: {reading}')
                reading += 1
                write_to_lcd(display)
                sleep(1)
                lcd.clear()
            except Exception as e:
                print(e)
    except KeyboardInterrupt:
        print()
        cleanup()

    # ---------- CLEANUP ---------- #
    cleanup()