Inspired by an recent post about a master/slave powerboard from Jaycar but no longer available, i found this online at a resonable proce.
The main equipment i.e. the TV or PC is plugged into the Control socket and your peripheral equipment is plugged into the 4 Auto sockets.
When the main equipment is turned off the unit senses the drop in power levels and will automatically cut the power to the auto sockets. When the main equipment is turned on again the process is reversed.
The unit also has one always on socket for leaving essential equipment turned on.
https://www.powerwise.co.nz/products/easy-off-auto-power-boa…
I've also found this 8 Watt LED Sensor Bulb interesting.
https://www.powerwise.co.nz/products/led-light-bulbs/8-watt-…