2 second trigger circuit timer

[ese2709]

Hi..

i have a home theater player and lcd tv... when i on tv the home theater will on together..

in my mind i want to use usb port from TV that when i on TV.. 5V from usb port (usb power will on until i off TV) i will use for the signal input to timer circuit. if the circuit detect signal from TV, it will on a relay for 2 second then off the relay. this relay is connect to standby switch of home theater player. then if i off TV so the power from usb is off and circuit detect no signal from TV, it will on the relay for 2 second then off. this will make the home theater player go to standby mode. the power source for the circuit i will connect to standby power from home theater power. that is my teory.

so someone can help me how to buit the circuit. if the relay can change to IC is better.