How can I control iPhone without touchscreen?

I want to control the iPhone without using the touchscreen. Specifically, I want a custom app to receive simple commands through pushing of 3 or 4 external buttons. I understand this can be done through the dock pins 12 and 13. I think I would need a microcontroller that would then send input to the app. I just dont understand the technical issues or possiblities with this approach.

Another idea is to use bluetooth connectivity. Once again, 3 or 4 buttons sending 3 or 4 differnet commands to the app. I just want to be able to scroll through options in the app or change a few settings. Once again, not sure of the technical issues or possiblites with sending input to apps via bluetooth.

For example, my app is a stopwatch. I want one button to start the timer, once button to record laps, one button to scroll through specifics of each lap once completed, and one button to stop the timer.

I also need to understand if I can disable the screen lock so I can avoid the SLIDE TO UNLOCK since I wont be able to access the touchscreen.

I think I will need to jailbreak the phone or work with Apple on hardware accessiblity but I'm just trying to figure out how to accomplish this.