[the-kenny]

Quite funny - I know someone who uses a similar setup to send GPS Coordinates for a Quadcopter and a Plane via the audio channel of the video link (he flies the Quadcopter/Plane with video goggles) to the ground station. There, an Arduino controls some stepper motors to point directional antennas at the copter/plane.

Project is at https://github.com/KipK/Ghettostation - video at https://www.youtube.com/watch?v=tiO4YCX7hJo - you can hear the modulation in https://www.youtube.com/watch?v=nm0okv8mTsg

[bri3d]

Cool! I hadn't seen that project before, although I'd seen a few other telemetry-over-audio solutions.

They usually use simple FSK just like the "real life" helicopter in the article.

Here's an example of a common simple protocol:

http://www.flytron.com/pdf/audio_modem.pdf