Hey, good on you developing for the blind, they are a often forgotten user base that is growing for smartphones. I also developed an application for
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One thing i would recommend when thinking of ideas is try using the TalkBack accessibility features in Android. They really do a lot to let you know whats going on on the phone. Use that and try to see what's not helpful. For example, i opened up my default camera application (Moto X) and the reverse camera button and video capture button translated to "Unlabeled button 48" and "Unlabeled button 96" when focused upon. Thus my idea for a blind camera was born.