Arduino Development for OSX and iOS (2015)
4. Controlling Arduino from iOS
4.2 Controlling Arduino from iOS
The first method can be used to control Arduino from your iOS devices is to use iPad/iPhone TTL cable from Redpark, http://redpark.com/products/ . Redpark provides some code samples to illustrate how to use. You can implement Firmata on this case.
The second approach is to use Bluetooth LE shield for Arduino. You can get this shield from your local electronics store or online store. To develop Bluetooth on iOS, it's not easy. Apple provides MFI program, https://developer.apple.com/programs/mfi/ , so hardware vendors can contribute to build hardware accessories for iOS devices such as iPod, iPad and iPhone. I have a plan to writa a book about Bluetooth iBeacon programming to explore these features.
The third approach is to use WiFi from iOS devices. To implement this approach, you also need WiFi shield for Arduino board.
In this chapter, we use the third approach but I don't use WiFi shield for Arduino. I attach my Arduino via USB and then implement Firmata. To expose our Arduino which is enabled to be controlled from External, I use Node.JS as web server.