Awesome
Quietnet
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.
Usage
run 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.
Installation
Quietnet is dependant on pyaudio and Numpy.
Better Projects
Quietnet is just a toy! Here are some more robust and polished projects to look at: