sketches of how my idea would work..

ok so looking at the way morse code is inputted, the use of metal contacts could be done on the mobile back.



you can clearly see the contacts here on a lever when pressed would make them contact and give a signal.

Here i have shown a quick line drawing on my mobile phone showing the areas of the phone applicable to this project.



namely the camera positions and the huge amount of free space on the back of the handset. aswell as mic positions which could be used for the other idea of tapping the mic for the sound input over a tapping contact.