Electronic "relay" solidstate with 3-15V DC control input is used for this project
A mecanical relay rated for mains with a 5V coil will also work
but I like the lifetime a solidstate relay will give me, with no moving parts and no wear !
now I can plug in my monitors and printer and hifi and watercooling pump, and whatever else used with my PC
then it will be turned off and on with the PC, saving power when PC is not in use, nice.