I would like to stream music from my Apple devices to my kitchen. I've got an old amplifier and passive speakers.
I know that I can simply connect my airport express to the LAN or WiFi and to the ampli as line input, but I would like the ampli to turn on only when there is a line input signal, and then automatically turn off after an idle time, in a way similar to many Subwoofers.
In this way only the AirPort Express will be always powered.
Is there a device or a simple way to do this job?