How do I make a Android phone play sounds remotely? I'm doing a Lego EV3 robot for a project. It needs to play sounds (like a soundboard app on a phone, but triggered remotely). Sadly, the speaker on the EV3 brick is too quiet for this. I got the idea to use my old phone connected to a Bluetooth speaker. Sadly, I can't find any apps that already do this and I have no programming experience. Is there another way to remotely trigger playback of a sound file stored on the phone? I'm okay with rooting the phone.

EDIT: I guess I didn't make that clear enough... I want to hold my phone in my hand and with that phone I want to make my other phone play short MP3 files. Without any wired connection. God dammit is English hard...
Have you tried airdroid https://www.airdroid.com/ it's very easy to use!

Or you can try somthing like https://www.logmein.com/ it's a cloud-based remote connectivity service a bit more complicated to setup 

I hope my answer was helpful