You'll need to measure lightness in the preview, perhaps in the whole image or a specific region. Possibly you'll need some kind of calibration to know what is a 1 and a 0
Such detection can be done with opencv, which is overkill but will work, or subsampling the preview, whatever you prefer
Then you'll need a morse software "decoder" based on the light and timing detected
Hi JordiCP, thank you for your help.
Really it will be enough to catch the preview on photo mode and process the bright changes on realtime.
I was seeing different camera libraries, but I need it to work on API 19.