Possibility to use (android) phone as a controller

[RandomModderJDK]

I want to play on my ipad with 2 controllers. But I don't have two real controllers. On the iPad you can only use one emulated controller.

My idea was that you could use e. g. two phones that use their screen as a controller. The phones would connect over wifi(or bluetooth?) and then send the controller inputs to the iPad and then forward it to the emulated wii.

I thought about an http server that has controls there, but I don't know about the performance. This would be the best cross platform(ios and android) solution.