How to connect smartphone and digital piano to detect notes?

[miretogo]

Problem: I use a piano learning app that detects via the smartphone's microphone if I play the correct notes on the real (digital) piano. However, when I play multiple notes simultaneously, the app sometimes incorrectly detects the notes I played.

Desired solution: The app's help texts mentions that the smartphone and the piano can be connected via midi.

Question: What input/output does the piano need for that? "Midi in"? "Midi out"? "Midi through"? Also, what cable do I need for that?

Any help is much appreciated

 

[cdcastillo]

I'm guessing you have an iPhone, if so, you'll need this kind of cable, connect the midi out [USB] from the piano (if there is only one USB plug, it usually is a midi out one) into the smarthphone and maybe select the input in the specific app you're using.

 

[miretogo]

Thank you for help and even making a photo to illustrate! My digital piano only has a round audio jack for headphones. I'll need another piano with MIDI out, apparently.