From charlesreid1

Robot36 is an Android app that allows you to send and receive slow scan TV (SSTV) signals (pictures in the form of audio signals). These are about 3 kHz wide.

Running Robot36 is dead simple. Just download the app, run it, and pick your modulation scheme. It uses the microphone onboard the phone to pick up the SSTV signals through the mic. Hold it up to the speaker of the device creating the SSTV signals, or up to a radio receiving an SSTV signal.

Slow Scan TV with Android from charlesreid1 on Vimeo.