Two dimensional data matrix barcodes are presented on the LED matrix display. Dedicated application for the Android based smartphones process a sequence of the modified DataMatrix barcodes.
More info:
A. Łutkowski, P. Skulimowski, P. Poryzała “An optical data transmission system for blind persons by means of a mobile phone with the Android operating system”, International Journal of Adaptive Control and Signal Processing, Article first published online: 1 SEP 2014, DOI: 10.1002/acs.2514, Volume 28, Issue 12, pages 1504–1513, December 2014