controlling a gpio with either playstate or a button at the purchaser?

[ashthespy]

Take a look at the Plugins category what you seek you shall find there

There are quite a few ways to achieve what you want - there are either general GPIO control plugin, or a more purpose specific one aptly named:

Amplifier Switch Plugin

Dear community, I’m happy to present my first plugin to you. The Amplifier Switch was born out of a need: I’m using an external Class-D amplifier that will be inaccessible in in it’s final case. While the RPI with volumio should be powered all the time, the amp clearly shouldn’t. I also didn’t want to turn the amp on/off by hand every time. Once activated, the AmpSwitch plugin will listen for status changes in the player and automatically turn on/off a user-selected output when music starts/st…