12vdc 10 minute Off-Delay Timer - Need help please.

Hi folks.

I'm new to this whole forum posting lark so please be gentle with me. From reading a ton of different posts within these and other forums, I reckon that you clever guys here are likely to be able to help me solve this.

Project brief:

To create an off-delay circuit for an external cooling solution for an Xbox 360 games console.

Basically, I have an Xbox 360 console which used to have a problem with the 3RLOD, I decided to remove the stock heatsinks and install a Koolance external water cooling system. This has remedied the fault with the console superbly (the console now operates at a max. load temp. of 43 deg. C.) and the 3RLOD hasn't returned in over 6 months of use since the mod was completed.

The issue which I have however, is that the external cooling solution must first be powered on from it's own seperate 12vdc power supply before the console can be powered on, aswell as having to remember to also switch off the cooling solution once I have had enough of getting my butt kicked at Halo3 by some grotty little 5yr old. I am concerned that either I might forget to do this one day or somebody else will come along and have a play but forget to turn on the cooler, which will most certainly lead to my Xbox 360 burning out.

I would like to create a circuit whereby upon powering on the Xbox 360, an off-delay timer circuit of some sort, fed from the Xbox 360's internal 12v supply, switches & holds on the seperate 12v supply to the cooler using a latching relay, then upon powering down the Xbox 360, the circuit will hold in the seperate 12v supply to the cooler for an additional 10 mins or so to allow it time to dissipate any residual heat from the system. I have read in places about using a 555 timer but i'm unsure exactly how to accomplish this.

Although the Xbox also operates using 12vdc which can be used to power the circuit, the seperate 12v supply must feed the cooler. I wouldn't like to run the risk of overloading the Xbox 360's PSU.

I would be very appreciative of any help that you guys could offer.

Thanks, WinMXer.

 

I'm just being extra cautious with the delay, but i'm sure that I want to incorporate it.

Do you have any idea of how to construct the circuit?