cell phone setting

I want a very simple cell phone app that can be downloaded on any phone android iPhone a regular cell from sprint or any other carrier. All the cell phone app should do is when you press the number *54 it would ask you what you would like to put for an away message so that when receiving a text in *54 mode or drive mode that it would automatically reply with the text you loaded after pushing *54. For example if someone text-ed you while you were driving, and you wanted to respond but it wasn't safe because you were driving it would automatically reply with the custom message that you put in after pressing *54 (a.k.a drive mode) ONCE AGAIN YOU WOULD PRESS *54 THEN THE Message "I WILL CALL YOU WHEN I'M OFF THE ROAD" THEN # TO SAVE THE MESSAGE AND TO GET OUT OF THE MODE YOU WOULD JUST PRESS *54 TO UNSET AND ERASE THE MESSAGE. I understand that it will have to be programed on several types of platforms but i would like to create this feature so i can make it available for free on my site for anyone to download for free.