DFPlayer signal to arduino question

Hello,

I have the dfplayer working with the ardiuno, i can push some buttons to hear some jingles.
Its works fine, simply when a button pressed, it send commando myDFPlayer.playFolder(2, 2); to play the second file in map 2, great.

But i have a other thing, also there is a music playing on a musicaudio player to arduino, works fine, when i pressed the sample button for the dfplayer, its send first a command:
setvolume(0) so the music from the other musicaudio goes to volume 0 (mute)
after that the dfplayer is playing file 2 from map 2.
But when the jingle is stopt, then he must send a command setvolume(10) back to the arduino to turn the music volume up.

Its like the blue led on the dfplayer, its on when its play a file, and wil be off when the file has be end/stopt.

So what can i use the send the arduino the command setvolume(10), how trigger i the command from the dfplayer?

Or is a connection from the led to one of the pins from the arduino a option?

I hope someone can explane me.

Thanks allot.

Kinder regard
Marcel