IR Switch for LED

I am a real neophyte at this, so please excuse my ignorance.

I am trying to design a circuit to turn on a blinking LED when an IR Emitter-Detector beam is broken. The distance between the Emitter and Detector will be approximately 6 inches. It will be located such that shaded daylight will fall on them. The circuit I designed (Microsoft Visio) with parts specifications is attached. I would appreciate any comments regarding the circuit and/or its components.

Specifically, I would like someone who is much more knowledgeable regarding the math to validate, or correct, the resistor values I have.
Further, any thoughts on the life of the 3-AA battery pack that I propose to use. I think the IR Emitter-Detector will continuously draw some amount of current.

Thanks for the help and your insight.

It looks like the detector is upside down.
Running the emitter at maximum power is maybe to high - seems like a 56 ohm 1/4 watt resistor would run it at about 50 ma. This would help the battery life.
You may need to experiment with Rd or make it adjustable.
Here is a link with some ideas on shielding and circuits.

**broken link removed**

Alkaline AAA have 1200 ma hour ratings so you might get 20 hours from a set. How much were you looking for?

Yup. I must have been standing on my head when I drew the circuit. I edited it and I think it's drawn correctly now.

ronv: Thanks for the link. I was hoping to get months of use from one set of batteries. Maybe that's impossible.