Is there a repeating, vibrating timer app for the iPhone that supports app-switching? When studying, I used to use one of those cheap digital kitchen timers that chirps every ten minutes as a little reminder of how fast time was passing -- it helped me keep track of time without the temptation to constantly glance at the clock.

The kitchen timer gave out on me recently, so I've been looking for an iPhone app to replace it. Ideally, it would have an on and off setting, and when on, would periodically vibrate in my pocket every ten or fifteen minutes.

Unfortunately, the apps I've found are quite chintzy and don't support switching between apps, or stop as soon as the phone is set to sleep -- and either of these is a deal breaker.

Are there any iPhone apps out there do what I'm looking for?

(I've been burned by a couple of paid apps that turned out to be lemons, so I'd be most grateful.)
I would suggest you use an interval timer like this. IntervalTimer

Just customize it to your needs and don't care about the high and low intensity options it has. If you adjust them you can have a perfect vibrating timer