Simple chat program using near ultrasonic frequencies. Works without Wifi or Bluetooth and won't show up in a pcap.
Note: If you can clearly hear the send script working then your speakers may not be high quality enough to produce sounds in the near ultrasonic range.
python send.py in one terminal window and
python listen.py in another. Text you input into the send.py window should appear (after a delay) in the listen.py window.
Warning: May annoy some animals and humans.