I would like to try using my iPhone to control Arduino and searched Youtube for some instructional videos. Found a few but the Apps they were using are no longer on the App Store. What is the best free app that will allow me to try some remote control projects using my iPhone. I have looked on the App store but it is not clear if they would useful for what I need. My thoughts are that if I can turn an LED off and on with my iPhone then I should be able to do a multitude of other things using a variety of components. I was going to start with an HC-05 or and HM-10 Bluetooth unit.
Any thoughts or advice would be much appreciated.