I have a board on which a microcontroller reads the output from a sensor. I am thinking of connecting it to an iPhone so that the iPhone can read data from it. The board should also be powered by iPhone/iPad. If it were in Android, I would look for the docs related to USB On-The-Go. But I am not sure what I should do with iOS devices. Can anyone give some hints? Thanks!
Update: I just find one needs to participate Apple's MFi program to develop accessories for Apple devices. So it may or may not be something for hobbyists. But apart from that, I am still eager to know the technical solution to my question.