Like in similar questions, I have my Pi on my TV and it currently draws power from the TVs USB. Fingers crossed, it currently works, but surely the Pi should have a better supply.
Now, the good point of the current config is that the Pi is powered on exactly when and if the TV is switched on.
How can I reproduce this when powering the Pi externally? Normal USB Relays seem to use the "data" on the USB to configure the relays; I would need one that most simply switches on when the TV powers up its USB and switches the Pi off as soon as the TV is powered off and consequentially its USB out goes down. Like an USB relay simply controlled by USB power, not data.
Thanks for any ideas!