There are devices such as the iLevil and Aeolus Talos, but it would be be highly not recommend to rely on them. I’d hate to think the that they did or for anyone to consider fitting one as a primary instrument, despite an aircraft being experimental, limited or otherwise.
I also note that in the pic that their iPad is not plugged in. The better attitude products with external sensors used a wired USB data cable connection.
This is the Talos device that I use. It does NOT use the gyros in the iPad.