Always wanted to create an Android version of an Robot36 decoder since I got an Android device.
So here it is and its open source (Apache License Version 2.0):

https://github.com/xdsopl/robot36/tree/android

Patches are welcome :)

It decodes the following modes at the moment:

Robot Modes: 36 & 72
PD Modes: 50 90 120 160 180 240 & 290
Martin Modes: 1 & 2
Scottie Modes: 1 2 & DX
Wraase Modes: SC2 180

You can even watch old B/W or unsupported modes in the "Raw Mode".

If an calibration header gets detected the resulting image will be saved in the "Pictures" directory and can be immediately seen in the Image gallery.

Switching away to another application will not stop the decoder and will continue to run in background.
To stop the decoder you must exit via the "back" button of Android.

Here you can find my wife's free open source SSTV Encoder:

https://play.google.com/store/apps/details?id=om.sstvencoder

You're welcome to join our "Robot36 SSTV Alpha Testers" community on Google+ to help test alpha releases:

https://plus.google.com/u/0/communities/106204623850343150882

Here a schematic for a line or headphone output to microphone input converter:

https://sites.google.com/site/xdsopl/converter

There are still some things that need to be addressed but for now: please enjoy testing :)