There are many different kinds of Augmented Reality
But different AR tools also make use of a device's accelerometer or compass to create immersive experiences.
The tools shown here use Image Markers, and are great fun. All you need to do is take a picture that would be a good Trigger Image.
You then upload your Trigger Image and overlay a movie on top of it. When someone points their device at it the movie then plays. They are very easy to make and very engaging.
Both these tools are wonderful to use and can be used in developer/demo mode, which means that if you want to create an immersive AR experience just for you or for a single device, you can do so.
You have to pay when you want to publish your experience to the world.
Not free, but you can use it developer mode to create compelling image-based Augmented Reality experiences. Great tool