I like the clock Idea, but it's very hard to actually take something out of your microwave. I would post my creation, but I think that's spamming... Edit: ok then...
I have a better timer for you to use. 3 digits @ 14 wifi frequencies a digit. Smaller, too. All you will have to do is create a electrical impulse device that dosent overload it.
Eh, it's a bit too overpowered. Perfect for experimenting but not too good for cooking food. It turns your food to plasma. I wouldn't want to stick that in my mouth. lol